This document provides information about ecology notes on energy and material cycling in ecosystems. It discusses the key roles of energy and various biogeochemical cycles, including the carbon, nitrogen, water, oxygen, and phosphorus cycles. The three main points covered are: 1) Energy flows through ecosystems in a one-way path and is required by organisms but is lost as heat or low-temperature emissions. The laws of thermodynamics govern energy flow. 2) Biogeochemical cycles recirculate essential elements like carbon, nitrogen, water, oxygen, and phosphorus between organisms and the environment. These cycles are important for maintaining life. 3) Human activities can disrupt natural cycles, like increasing carbon dioxide levels

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Name Raza Muhammad
BS Zoology
Whatsapp 03467830036
Ecology notes
Unite 1
Energy
Energy plays a critical role in basic human survival. Energy has important implications
for health. Energy is also crucial to transportation and industrial processes. However,
production and use of energy, if not properly controlled may be accompanied by
adverse health and environment impacts. In developing countries, biomass accounts
for about one-third of all energy use, and in some of least-developed countries, for as
much as two-thirds. Open fires impair indoor air quality, add to the risk of accidents
and jeopardize food hygiene.
In general, the adverse effects on the environment of human activities are many and
appear to be growing in intensity, and affecting larger and larger areas. Current and
future potential pressures on the environment have major implication for health.
Energy Flow and Material Cycling
The existence of the living world, including human life, depends upon the flow of
energy and the circulation of materials through the ecosystem. Both influence the
abundance of organisms, the rate at which they live, and the complexity of the
community. Energy and materials flow through the community together; one can not
very well be separated from the other. But, the flow of energy is one way; once

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used by the community, it is lost. Material on the other hand re-circulates. An atom of
carbon or calcium may pass between the living and the non-living many times or it may
even exchange between the ecosystems.
Laws of Thermodynamics
Energy flows in a one-way path through biological systems and eventually into some
low-temperature sink such as outer space. Two laws of thermodynamics describe the
behavior of energy.
first law of thermodynamics states that energy is conserved; that is, it is neither created
nor destroyed under normal conditions. It may be transferred from one place or object
to another, but the total amount of energy remains the same. Similarly, energy may be
transformed, or changed from one form to another (e.g. from the energy in a chemical
bond to heat energy), but the total amount is neither diminished nor increased
Definition: The laws of thermodynamics are important unifying principles of
biology. These principles govern the chemical processes (metabolism) in all biological
organisms. The First Law of Thermodynamics, also known as the law of conservation
of energy, states that energy can neither be created nor destroyed. It may change from
one form to another, but the energy in a closed system remains constant.
The Second Law of Thermodynamics states that when energy is transferred, there will
be less energy available at the end of the transfer process than at the beginning. Due to
entropy, which is the measure of disorder in a closed system, all of the available energy
will not be useful to the organism. Entropy increases as energy is transferred.
In addition to the laws of thermodynamics, the cell theory, gene theory, evolution,

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and homeostasis form the basic principles that are the foundation for the study of life.
First Law of Thermodynamics in Biological Systems
All biological organisms require energy to survive. In a closed system, such as the
universe, this energy is not consumed but transformed from one form to another.
Cells, for example, perform a number of important processes. These processes require
energy. In photosynthesis, the energy is supplied by the sun. Light energy is absorbed
by cells in plant leaves and converted to chemical energy. The chemical energy is
stored in the form of glucose, which is used to form complex carbohydrates necessary to
build plant mass. The energy stored in glucose can also be released through cellular
respiration. This process allows plant and animal organisms to access the energy stored
in carbohydrates, lipids, and other macromolecules through the production of ATP.
This energy is needed to perform cell functions such as DNA replication, mitosis,
meiosis, cell movement, endocytosis, exocytosis, and apoptosis.
Second Law of Thermodynamics in Biological Systems
As with other biological processes, the transfer of energy is not 100% efficient. In
photosynthesis, for example, not all of the light energy is absorbed by the plant. Some
energy is reflected and some is lost as heat. The loss of energy to the surrounding
environment results in an increase of disorder or entropy. Unlike plants and other
photosynthetic organisms, animals cannot generate energy directly from the sunlight.
They must consume plants or other animal organisms for energy. The higher up an
organism is on the food chain, the less available energy it receives from its food sources.
Much of this energy is lost during metabolic processes performed by the producers and

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primary consumers that are eaten. Therefore, much less energy is available for
organisms in higher trophic levels. The lower the available energy, the less number of
organisms can be supported. This is why there are more producers than consumers in
an ecosystem. Living systems require constant energy input to maintain their highly
ordered state. Cells, for example, are highly ordered and have low entropy. In the
process of maintaining this order, some energy is lost to the surroundings or
transformed. So while cells are ordered, the processes performed to maintain that order
result in an increase in entropy in the cell's/organism's surroundings. The transfer of
energy causes entropy in the universe to increase.
Energy flow in ecosystems
The sun is the main source of all our energy. It is a continuously exploding hydrogen
bomb where hydrogen is converted to helium with the release of energy. This energy is
mostly in the region of 0.2 to 4 mm (Ultraviolet to Infra-Red). Around 50% of the
radiation is in the visible range. The energy reaches the earth at a constant rate called
the Solar Flux or Solar Constant, which is the amount of radiant energy crossing unit
area in unit time. This value is approximately 1.4 KJ per sq. meter per second.
Chlorophyll bearing plants convert this energy from the sun into carbohydrates and
sugars using carbon di oxide and water. This process is known as Photosynthesis. The
generalized form of the photosynthetic reaction is
6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O
Carbon dioxide, + water → glucose + oxygen +
water
The carbohydrates produced by photosynthesis undergo further modifications such as

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Production of proteins and nucleic acids by combining with nitrogen, phosphorous and
sulphur. Starch polymerizes to cellulose.
The sun’s energy thus enters the living beings through photosynthetic reactions and is
passed from one organism to another in the form of food. The flow of energy is uni
directional and is governed by the thermodynamic law that states that Energy is neither
created nor destroyed and can transform into different forms.
When energy travels from producers to different levels of consumers in an ecosystem
there is loss at each level due to the energy dissipated as heat during the metabolic
processes of the organisms. Hence as we move step by step away from the primary
producers the amount of available energy decreases rapidly. Hence only 3 to 5 feeding
levels are possible. These are referred to as Tropic levels
Food Chain and Food Web
The food chain is an ideal model of flow of energy in the ecosystem. According to this

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scheme the plants or producers are eaten by only the primary consumers, primary
consumers are eaten by only the secondary consumers and so on. The producers are
called Autotrophs.
A food chain has three main tropic levels viz. Producers, consumers and Decomposers.
The energy efficiency of each tropic level is very low. Hence shorter the food chain
greater will be the availability of food.
A typical food chain in a field ecosystem might be
Grass — Grasshopper — frog — Snake — Hawk
The grasshopper eats grass, the frog eats the grasshopper, the snake eats the frog, and
the eagle eats the snake.
Food web is a network of interconnected food chains showing the energy flow
through part of an ecosystem. These are a more accurate way of showing feeding
relationships than food chains, because most animals have more than one food source.
For example, in the food webs in figure below

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Food webs are easily unbalanced, especially if one population of organisms in the web
dies or disappears. This may happen for a number of reasons, including:
• over–predation or hunting
• disease
• pollution
• use of pesticides
• lack of food (or other resources)
• emigration.
For example, in the food web here, goat were killed by hunters the loin would have
only rabit to eat.
Material cycles in ecosystems/ biogeochemical cycles
All elements in the earth are recycled time and again. The major elements such as
oxygen, carbon, nitrogen, phosphorous, and Sulphur are essential ingredients that make
up organisms.
Biogeochemical cycles the flow of chemical elements and compounds between
organisms and the physical environment.
OR
The cyclic movement of nutrient material between the biotic and abiotic environment is
called Biogeochemical Cycle.
As an element moves through this cycle, it often forms compounds with other elements
as a result of metabolic processes in living tissues and of natural reactions in the
atmosphere, hydrosphere, or lithosphere.
Such cyclic exchange of material between the living organisms and their non-living
environment is called Biogeochemical Cycle.
Following are some important biogeochemical cycles −
• Carbon Cycle
• Nitrogen Cycle
• Water Cycle

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• Oxygen Cycle
• Phosphorus Cycle
• Sulphur Cycle
Carbon Cycle
Carbon is a very abundant element on our planet. It is found in both the abiotic and
biotic environment. Carbon is constantly cycled between these environments.
Carbon exists in the abiotic environment as:
1. Carbon dioxide gas, CO₂, in the atmosphere. It reacts with other compounds.
2. Carbonate rocks like limestone - CaCO₃
3. Deposits of fossil fuels, (oil, natural gas and coal). These are derived from once
living things.
4. Dead organic matter, (fallen leaves, skeletons, twigs). All organic matter contains
carbon, which decomposes into the abiotic environment when it is dead.
Carbon enters the biotic environment through:
1. Photosynthesis. Plants convert carbon dioxide CO₂, water H₂O and light energy into
Chemical energy and glucose, C₆H₁₂O₆
CO₂ + H₂O + light energy → C₆H₁₂O₆ + O₂
As plants are consumed, the carbon is transferred and moves up the food chain.
2. The formation of shells and skeletons of marine animals. The carbon dioxide from
the air reacts with water, causing the formation of CO₃. This is what marine shells and
Skeletons are made from.
Carbon returns to the environment by:
1. Cellular respiration. Carbon dioxide produced during respiration and is exhaled into
the atmosphere.
C₆H₁₂O₆ + O₂ → CO₂ + H₂O + chemical energy
Some of the exhaled carbon dioxide will be absorbed by plants for photosynthesis.
2. Decomposition of living things. When organic material dies, it decomposes and the
carbon returns to the soil.

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3. Burning. Combustion of organic material, (forest fires, etc.), causes the carbon from
the organic tissues to enter the atmosphere
The carbon cycle is naturally occurring, but humans can cause major disruptions.
1. Deforestation /Removal of photosynthesizing plants through clear-cutting and
deforestation.
○ Carbon cannot enter the biotic environment to the same extent.
○ Atmospheric oxygen levels decrease because CO₂ will not be converted into
C₆H₁₂O₆ + O₂.
2. Combustion of fossil fuels.
○ Fossil fuels are used abundantly in society.
○ Combustion of fossil fuels cause carbon levels to increase in the atmosphere in
the form of CO₂ and CH₄. These are both greenhouse gases.
○ Increased greenhouse gases cause global temperatures to rise. This creates
many ecological and biological problems for the planet
Carbon Cycle

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Nitrogen Cycle
The nitrogen cycle is the transformation and movement of nitrogen between the
geosphere and biosphere
Although there is an abundance (78%) of nitrogen in the atmosphere, most plants
cannot use free form of nitrogen.
The steps of the nitrogen cycle are the following:
○ Nitrogen Fixation
○ Nitrification
○ Denitrification
○ Ammonification
○ Assimilation
○ Eutrophication
Nitrification
Nitrification is the process completed in two steps in which ammonia is converted to
nitrites (NO2 -) and then to nitrates (NO3 -).
● Two different species of bacteria that are present in the soil oxidize the ammonia into
inorganic forms of nitrogen
● The rate of nitrification is determined by these factors:
○ temperature dependency: rapid changes in temperature do not produce rapid
changes in growth
○ oxygen intake: nitrifying bacteria are sensitive to low oxygen concentrations
○ pH dependency: nitrification occurs the fastest when the pH is between 8 and 9
○ prevention substances- many substances can prevent nitrification reactions such as
metals
Assimilation
Assimilation is the is the process by which living organisms incorporate NO3 - and
NH4+ ammonium formed through nitrogen fixation and nitrification

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● Plants take in this form of nitrogen via the roots and incorporate them into nucleic
acids and plant protein
● Animals are then able to receive and utilize the nitrogen from plant tissues through
consumption
Ammonification
Ammonification occurs when a plant or animal dies or excretes waste
● Decomposers, such as bacteria and fungi, first break down the proteins in the organic
matter
● This releases ammonia, which dissolves with the water in the soil
● Ammonia then combines with a hydrogen ion to create ammonium
De-nitrification
De-nitrification is the process in which microorganisms, such as bacteria, break down
nitrates to metabolize oxygen .This releases nitrogen gas back into the atmosphere,
completing the cycle
Water Cycle
The water cycle is the movement of water from the ground, to the air, and back to the
ground

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OR
There is a constant and continuous exchange of water between air, land, sea and living
beings.
Considerable part of the solar energy incident on the earth is used for the massive
evaporation of water from the oceans, seas and other exposed water bodies water enters
the atmosphere by the process of evaporation and by transpiration from leaves.
• Evaporation- process by which energy from the sun causes water on the surface of the
earth to change to water vapor, the gas phase of water, the first step in the water cycle.
• Transpiration- the process by which moisture is carried through plants from roots to
small pores on the underside of leaves, where it changes to vapor and is released to the
atmosphere. It condenses and falls from the atmosphere as precipitation.
• Condensation- process by which water vapor changes back into a liquid, the second
step of the water cycle.
• Precipitation– the process by which water returns to the earth in the form of rain,
snow, sleet, and hail, the third step of the water cycle
Oxygen cycle
The atmosphere contains about 21% oxygen. The atmospheric oxygen enters the living
organisms, as a gas required in respiration.

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During this process carbon dioxide and water are formed.
C6 H12 O6 + 6O2 —–> 6 CO2 + 6 H2O + energy
The metabolic water thus formed is added to all other water present in living organisms
and as such it may undergo three possible fates. Some of it may be excreted and so
added to the water content of the environment. Another part may be used as a building
material for the formation of more living matter. A third possible fate of the water
within organism is its consumption as a fundamental raw material along with the
carbon dioxide in photosynthesis
In this process the oxygen is liberated as shown by the following equation:
6 CO2 + 6 H2O + light energy
Such free oxygen may now again be used in respiration or it may be returned to the
environment as molecular atmospheric oxygen, completing the cycle. Thus oxygen
enters organisms only through respiration and leaves through photosynthesis. In
intervening steps the oxygen is incorporated in water, and in this form it can interlink
with the water cycle or indirectly with carbon cycle.

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The oxygen in the atmosphere is the source of ozone (O3). The Ozone layer protects
organisms by preventing most of the ultraviolet and X-ray from reaching the earth’s
surface. The most recent factors affecting the oxygen cycle of the biosphere and the
oxygen budget of the earth in the man himself. In addition to inhaling oxygen and
exhaling carbon dioxide, man decreases the oxygen level and increases the carbon
dioxide level by burning fossil fuels
Phosphorus cycle
Phosphorus is an essential nutrient for living organisms. It’s a key part of nucleic acids,
like DNA and of the phospholipids that form our cell membranes. As calcium
phosphate, it also makes up the supportive components of our bones.
The phosphorus cycle is the process by which phosphorus moves through the
lithosphere, hydrosphere, and biosphere. Phosphorus is essential for plant and animal
growth, as well as the health of microbes inhabiting the soil, but is gradually depleted
from the soil over time. The main biological function of phosphorus is that it is required
for the formation of nucleotides, which comprise DNA and RNA molecules.
Specifically, the DNA double helix is linked by a phosphate ester bond. Calcium

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phosphate is also the primary component of mammalian bones and teeth, insect
exoskeletons, phospholipid membranes of cells, and is used in a variety of other
biological functions. The phosphorus cycle is an extremely slow process, as various
weather conditions (e.g., rain and erosion) help to wash the phosphorus found in rocks
into the soil. In the soil, the organic matter (e.g., plants and fungi) absorb the
phosphorus to be used for various biological processes.
Phosphorus Cycle Steps
The phosphorus cycle is a slow process, which involves key steps, as shown in the
diagram below and described as follows
Weathering
Since the main source of phosphorus is found in rocks, the first step of the phosphorus
cycle involves the extraction of phosphorus from the rocks by weathering. Weather
events, such as rain and other sources of erosion, result in phosphorus being washed
into the soil.
Absorption by Plants and Animals
Once in the soil, plants, fungi, and microorganisms are able to absorb phosphorus and
grow. In addition, phosphorus can also be washed into the local water systems. Plants
can also directly absorb phosphorus from the water and grow. In addition to plants,
animals also obtain phosphorus from drinking water and eating plants

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Return to the Environment via Decomposition.
When plants and animals die, decomposition results in the return of phosphorus back
to the environment via the water or soil. Plants and animals in these environments can
then use this phosphorus, and step 2 of the cycle is repeated.
Human Impact on the Phosphorus Cycle.
Humans have had a significant impact on the phosphorus cycle due to a variety of
human activities, such as the use of fertilizer, the distribution of food products, and
artificial eutrophication. Fertilizers containing phosphorus add to the phosphorus levels
in the soil and are particularly detrimental when such products are washed into local
aquatic ecosystems. When phosphorus is added to waters at a rate typically achieved by
natural processes, it is referred to as natural eutrophication. A natural supply of
phosphorus over time provides nutrients to the water and serves to increase the
productivity of that particular ecosystem. However, when foods are shipped from
farms to cities, the substantial levels of Phosphorus that is drained into the water
systems is called artificial or anthropogenic eutrophication. When levels of phosphorus
are too high, the overabundance of plant nutrients serves to drive the excessive growth
of algae. However, these algae die or form algae blooms, which are toxic to the plants
and animals in the ecosystem. Thus, human activities serve to harm aquatic ecosystems,
whenever excess amounts of phosphorus are leached into the water
Sulphur cycle,
Sulphur, like nitrogen and carbon, is an essential part of all living matter because
sulphur containing amino acids are always present in almost all kinds of proteins.
Plants can absorb directly the sulphur containing amino acids, e.g., cystine, cysteine,
and methionine but these amino acids fulfill only a small proportion or requirements
for sulphur. To fulfill rest of the requirements of plants, sulphur passes through a cycle
of transformation mediated by microorganisms. It accumulates in the soil mainly as a
constituent of organic compounds and has to be converted to sulphate to become
readily available to the plants.

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The sulpher cycle completed in the following steps
(a) Degradation of Organic Compounds to Release H2S: it is completed in three
steps
(i) Degradation of proteins (proteolysis) it liberates amino acids which generally contain
sulphur.
Protein degradation amino acid
(ii) Enzymatic activity of many heterotrophic bacteria result in the release of H2S from
further degradation of sulphur containing amino acids
(iii) Sulphates may also be reduced to H2S by the action of Desulfotomaculum bacteria.
Example;
(b) Oxidation of Hydrogen Sulphide (H2S) to Elemental Sulphur:
Hydrogen sulphide undergoes decomposition to produce elemental sulphur by the
action of certain photosynthetic sulphur bacteria, e.g., members belonging to the
families Chlorobiaceae (Chlorobium) and Chromatiaceae (Chromatium).

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Example:
Some non-sulphur purple bacteria, e.g., Rhodospirillum, Rhodopseudomonas, and
Rhodomicrobium, which are facultative phototrophs and grow aerobically in the dark
and anaerobically in the light, can also degrade H2S to elemental sulphur.
(c) Oxidation of Elemental Sulphur to Sulphates:
Elemental form of sulphur accumulated in soil by earlier described processes cannot be
utilized as such by the plants. It is oxidized to sulphates by the action of
chemolithotrophic bacteria of the family Thiobacteriaceae (Thiobcicillus thiooxidans)
Example:
(d) Reduction of Sulphates:
Sulphate is first reduced to H2S by sulphate reducing microorganisms under anaerobic
conditions. Many bacteria including species of Bacillus, Pseudomonas, Desulfovibrio do
this work. The mechanism of sulphate reduction to hydrogen sulphide involves, firstly,
the reduction of sulphate to sulphite utilizing ATP and, secondly, reduction of sulphite
to hydrogen sulphide.
Limiting Factor Definition
A limiting factor is a resource or environmental condition which limits the growth,
distribution or abundance of an organism or population within an ecosystem. These can
be either physical or biological factors which can be identified through a response of
increased or decreased growth, abundance, or distribution of a population, when the
factor is changed and when the other factors necessary to life are not.
Etymology

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The term limiting factor comes from Latin limitare, meaning “to bound” and from Latin
factor, meaning “a doer”, “performer”), from factus, meaning “done” or “made”.
Synonyms: limiting resource; ecological factor; constraining factor.
Principles and laws
The principle of limiting factors is defined as the principle whereby a factor that is in
shortest supply will limit the growth and development of an organism or a community.
There are three main laws which are bellow
(1) Liebig’s law of the minimum,
(2) Blackman’s law of limiting factor, and
(3) Shelford’s law of tolerance are the laws that explain the principles of limiting
factors
(1) Liebig’s law of the minimum,
Definition In the 19th century, the German scientist Justus von Liebig formulated the
“Law of the Minimum,” which states that if one of the essential plant nutrients is
deficient, plant growth will be poor even when all other essential nutrients are
abundant.
How It Works
It states that growth is controlled not by the total originality applied to plant growth,
where it was found that increasing the amount of plentiful nutrients did not increase
plant growth. Only by increasing the amount of the limiting nutrient (the most scarce)
in relation to “need”, was the growth of the plant improved.
(2) Blackman’s Law of Limiting Factors
A plant physiologist Blackman studied on limiting factors on the photosynthesis system
of plants. He stated that the biological factors are affected by a number of factors, but
the amount in which they affect the whole process is different. Let us take the example
of photosynthesis. Plants require adequate amounts of water, sunlight, chloroplast
temperature, carbon dioxide and chlorophyll to carry out photosynthesis. The scarcity
of any of these components will affect the process of photosynthesis.

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Any physiological process which is affected by more than one factor is governed by the
law of limiting factor.
The relative magnitude of factors is more important than the absolute magnitude.
A factor which is present in higher amounts may be a limiting factor in comparison to
the one present in smaller amounts. This is because the requirement of the factor
present in higher amounts is more.
When the rate of the process becomes constant due to a limiting factor, it can be
regulated by regulating the amount of the factor only which is limiting. For eg., a leaf
which can utilize 5mg of CO2 per hour in photosynthesis is exposed to certain light
intensity. If only 1mg of CO2 enters the leaf in an hour, the rate of photosynthesis is
limited due to the CO2 factor. As the concentration of CO2 increases, the rate of
photosynthesis is also increased. Any further increase in the CO2 concentration will not
affect the rate of photosynthesis. It will only increase if the intensity of light is increased.
(3)Shelford’s law of tolerance
Definition
It is a law stating that a certain organism’s survival and existence depend upon the
multifaceted set of conditions wherein each individual has definite minimum,
maximum and optimum ecological factors to establish success. It was develop by
American zoologist Victor Ernest Shelford in 1911.
The absence of an organism can be limited by the qualitative or quantitative
insufficiency from the various environmental factors which may come up to the limits
of tolerance for that organism. Environmental factors involved climatic change,
topographic location and biological necessities of both plants and animals. This law is
possibly the more precise indication of natural complexity. Each individual or a
population is subject to an ecological change that crop up the minimum and maximum
capacity to any complex environmental factors. The range wherein it carried out from
the minimum to maximum signify the limit of tolerance of an organisms, if all known
factors are actually within the particular range of a certain organisms yet it still fails, it
is important to consider extra factors of interrelationships with other organisms. It is

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been studied that an organisms may have an extensive tolerance for one factor yet a
slight array for another. When an organism has a wide range on all factors it indicates
that a certain organisms are most widely distributed and are contribute to augment
diversity in the community
Types of Limiting Factors
Density Dependent Factors, Density dependent factors are those factors whose effect
on a population is determined by the total size of the population. Predation and disease,
as well as resource availability, are all examples of density dependent factors. As an
example, disease is likely to spread quicker through a larger, denser population,
impacting the number of individuals within the population more than it would in a
smaller, more widely dispersed population.
Density Independent Factors
A density independent limiting factor is one which limits the size of a population, but
whose effect is not dependent on the size of the population (the number of individuals).
Examples of density independent factors include environmentally stressful events such
as earthquakes, tsunamis, and volcanic eruptions, as well as sudden climate changes
such as drought or flood, and destructive occurrences, such as the input of extreme
environmental pollutants. Density independent factors will usually kill all members of a
population, regardless of the population size.
On other hand limiting factor can be divided into the following
Physical and Biological Limiting Factors
Limiting factors can also be split into further categories.
Physical factors or abiotic factors include temperature, water availability, oxygen,
salinity, light, food and nutrients;
biological factors or biotic factors, involve interactions between organisms such as
predation, competition, parasitism and herbivory.
Physical factors or abiotic factors include temperature, water availability, oxygen,
salinity, light, food and nutrients;
Common examples of abiotic factors include:

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➢ Temperature
➢ Light
➢ Fire etc
Light
Light energy (sunlight) is the primary source of energy in nearly all ecosystems. It is the
energy that is used by green plants (which contain chlorophyll) during the process of
photosynthesis; a process during which plants manufacture organic substances by
combining inorganic substances.
The portion of the sunlight which can be resolved by the human eye is called visible
light. The visible part of light is made-up of wavelength from about 400 nm (violet) to
700 nm (red). The rate of photosynthesis is maximum at blue (400 – 500 nm) and red
(600 – 700 nm). The green (500 – 600 nm) wave length of spectrum is less strongly
absorbed by plants.Visible light is of the greatest importance to plants because it is
necessary for photosynthesis. Factors such as quality of light, intensity of light and
the length of the light period (day length) play an important part in an ecosystem
• Quality of light (wavelength or colour):
Plants absorb blue and red light during photosynthesis. In terrestrial ecosystems
the quality of light does not change much. In aquatic ecosystems, the quality of
light can be a limiting factor. Both blue and red light are absorbed and as a result
do not penetrate deeply into the water. To compensate for this, some algae have
additional pigments which are able to absorb other colours as well.
• Light intensity ("strength" of light)
The intensity of the light that reaches the earth varies according to the latitude
and season of the year. The southern hemisphere receives less than 12 hours of
sunlight during the period between the 21st March and the 23rd of September,
but receives more than 12 hours of sunlight during the following six months.
Based on the tolerance to intensities of light, the plants are divided into two
types. They are

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1. Heliophytes - (Greek helios, sun) Light loving plants. Plants which grow
well in bright sunlight are called heliophytes Example: Angiosperms.
2. Sciophytes -(Greek skia, shade ). Shade loving plants. plants which grow well
in shady conditions are known as sciophytes Example: Bryophytes and Pteridophytes.
In deep sea (>500m), the environment is dark and its inhabitants are not aware of the
existence of celestial source of energy called Sun. What, then is their source of energy?
• Day length (length of the light period):
Certain plants flower only during certain times of the year. One of the reasons
for this is that these plants are able to "measure" the length of the night (dark
periods). However, it was thought that it is the day length (light periods) to
which plants reacted and this phenomenon was
termed photoperiodism. Photoperiodism can be defined as the relative lengths
of daylight and darkness that effect the physiology and behaviour of an
organism
Photoperiodism can be defined as the relative lengths of daylight and darkness that
effect the physiology and behaviour of an organism
Short-day Plants
These plants flower only if they experience nights which are longer than a certain
critical length. The chrysanthemum (Chrysanthemum sp.), the poinsettia ( Euphorbia
pulcherrima) and the thorn-apple (Datura stramonium) are examples of short day plants.
• Long-day plants
These plants flower if they experience nights which are shorter than a certain
critical length. Spinach, wheat, barley, clover and radish are examples of long
plants.
• Day-neutral plants
The flowering of day-neutral plants is not influenced by night length. The tomato
(Lycopersicon esculeutum) and the maize plant (Zea mays) are examples of day-
neutral plants.

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EFFECTS OF LIGHT ON ANIMAL
Light is affecting normal pattern of day and night are very important for most living
things to function properly. The waking and sleeping patterns of many animals are
affected by the changes in light over 24 hours or during the year. The animal may be
• Diurnal; Many animals are diurnal, which means they will naturally wake up when
it gets light and go to sleep when it becomes dark.
•Nocturnal animals react in the opposite way. They sleep during the day and wake up
at night-time.
• Crepuscular animals that are active primarily during twilight, the time just before the
sun sets or rises.
Light also effect the life activity of animals like Migration, Hibernation, Animal eyes
Camouflage, Bioluminescence, Metabolism ,Photoperiodism and Biological clock
(Biorhythms) Mainly animals are affected by light with
Migration
Many animals are also affected by the change of season. The length of daylight affects
animals when to start migrating.
➢ Many birds migrate to countries thousands of kilometers away. They will use the
sun to help them find their way (navigate).
➢ Bees also use the position of the sun to navigate.
2. Hibernation
In some colder countries, the shorter days trigger hibernation in animals like bear.
These animals eat a lot in the warmer months to build up fat before sleeping in a
burrow, cave or hole during the cold winter.
Animal eyes
Insects, such as flies, have compound eyes, which is directly affected by light. Unlike
humans, some animals can see infrared and ultraviolet light.
➢ Bees can see ultraviolet light which helps them see flowers that reflect ultraviolet
light from their petals.

25. 25
➢ Other animals, such as the piranha, can see infrared light. Seeing infrared light
helps animals to catch their prey.
Bioluminescence
Many animals give out light. When animals make this light, it is call bioluminescence.
➢ Some animals use chemicals or bacteria inside the cells of their body to create
light.
➢ The male Malaysian firefly is one insect that produces a particularly spectacular
show.
➢ Many fireflies sit on the same bush and all flash their light at the same time
Effect on metabolism:
➢ By increasing in light intensity results increase in enzymatic activity.
➢ Solubility of gases decreases with higher light intensity
Photoperiodism and Biological clock (Biorhythms):
Diffenetion; Photoperiodism is the physiological reaction of organisms to the length of
night or a dark period
➢ Circadian rhythms: •It is mainly working with the Earth’s rotation by working
with day/ night with activity /sleep.
➢ Circatidal rhythms: •In this rhythms, tidal activities are affecting the working of
animal •By changes in high and low tides, the animals which are living in
intertidal zone alternately submerged in water and exposed to air.
➢ Circalunar rhythms: •It is synchronized with the phases of moon. With the
changes in phases animals are changes their color, size which is also known as
heteronersis.
➢ Semilunar rhythms: •It deals with spring tide and neap tide which is related to
the second and fourth quarter of moon
➢ Circannual rhythms: •The activities of animals are also affected by seasonal
changes during the year. Metabolic activities of animals are changes with
seasonal changes.
Ecological Factor #2. Temperature:

26. 26
Temperature
It is a measure of how hot or cold an object is compared to another object.
Temperature as a measure of the average kinetic energy of an object. It is measured by
the Thermometer. Temperature is one of the important factors which affect almost all
the metabolic activities of an organism. Every physiological process in an organism
requires an optimum temperature at which it shows the maximum metabolic rate.
Three limits of temperature can be recognized for any organism. They are
1. Minimum temperature - Physiological activities are lowest.
2. Optimum temperature - Physiological activities are Maximum.
3. Maximum temperature - Physiological activities will stop.
The optimal temperature is called cordinal temperature. The cardinal temperature
varies from species to species and in the same individual from part to part. The
distributions of plants, animals are also influenced by temperature.
Depending upon the response of plants to temperature of environment, the entire
vegetation of the earth can be divided into following four classes:
1. Megatherms:
Plants which required more or less constant high temperature throughout the year for
their optimal growth and development is a called megatherm e.g., dominant vegetation
of tropical rain forests.
2. Mesotherms:
These plants are capable of enduring considerably lower temperature during some
period of the year such as winter months, followed by high temperature, such as during
summers. Many plants of tropical, subtropical regions of the world can be included in
this class, e.g., vegetation of tropical deciduous forests.
3. Microtherms:
Plants of temperate regions of the earth need much lower temperatures for their growth
and development. These plants are incapable of enduring high temperatures even for a
few months of the year. All high altitude plants (upto about 3600 metres) of the tropical
and subtropical regions can also be included in this group, e.g., mixed coniferous forest.

27. 27
4. Hekistotherms: These plants are restricted only to arctic and alpine regions above
4800 metres in tropics and above 3600 metres in the temperate zones of the world. The
plants have the lowest thermal requirement and they are also adapted to short summer
which prevails in the extreme temperate regions of the world. They endure long and
extremely cold winter months without any permanent injury, e.g., alpine vegetation
A classification based on the relationships between organisms and environmental
temperature divides organisms into ectotherms and endotherms.
Ectotherms: are organisms who largely depend on external sources of heat to raise their
body temperature. Examples: protista, plants, fishes, reptiles etc.
Endotherms: Endotherms are organisms capable of generating heat internally in order
to raise their body temperature. Examples: birds and mammals. As the temperature
moves away from the thermo neutral zone, the endotherms expend more and more
energy to maintain body temperature. produce heat at a rate controlled by the brain.
Heat loss is moderated by insulator material (fur, fat etc.) and by controlling blood
flownear the skin surface.
Functions of Temperature:
The effects of temperature on plants and animals are:
1. Effect on metabolism:
As temperature regulates the activity of enzymes, it regulates the metabolic processes of
organisms. It affects the rate of transpiration, photosynthesis and seed germination in
plants. It also regulates the respiration rates and other metabolic activities in both plants
and animals.
2. Effect on reproduction:
(a) Plants:
Temperature affects flowering in plants. It also plays an important role in the
phenology (study of periodic phenomena) of plants.
(b) Animals:
The maturation of gonads and liberation of gametes take place at a particular
temperature that varies from species to species. Breeding also is affected in some due to

28. 28
temperature. The number of eggs laid by blowfly increases with increasing temperature
up to 32.5°C and thereafter decreases. The fecundity of animals is also affected by
temperature.
3. Effect on growth and development:
(a) Plants:
Extremes of high and low temperature have adverse effect on the growth of plants. Low
temperatures bring about diseases like desiccation, chilling and freezing injury.
Extremely high temperature causes stunting and death of plants — called heat injury.
(b) Animals:
Growth and development of animals are affected by temperature. Corals do not flourish
when the temperature of water drops below 21°C. In blow-fly, the incubation period of
eggs decreases with increasing temperature.
4. Effect on crossing over:
Temperature is seen to affect the crossing over and somatic expression of genes in
animals. If the larva or pupa are kept at low or high temperature it affects the
development of wings, eyes etc.
5. Effect on sex-ratio:
In rotifers and daphnids, temperature affects sex ratio. Under normal temperature,
daphnids lay parthenogenetic eggs that develop into females, while with the increase in
temperature they give fertilised eggs that develop into either males or females.
6. Effect on colouration:
Some species of mammals, birds and insects present in warm humid climates, bear
darker pigment than the races of species who resides in cool and dry climate. In Hyla
(tree frog) and Phrynosoma (horned toad), low temperature induces darkening of
pigments.
7. Effect on morphology:
The absolute size of an organism is affected by temperature. Mammals and birds attain
larger body sizes in cold regions than in warmer areas. Whereas, poikilotherms are
smaller in cold regions. Snout, ear, legs etc. of mammals are relatively shorter in colder

29. 29
areas than in warmer areas. The races of birds occurring in colder regions have
relatively narrower and more accuminate wings, while those in warmer areas tend to be
broader.
As per Jordan’s Rule, the fishes living in low temperature water regions tend to have
more number of vestibules than their counterparts living in the high temperature water
regions
8) Effect on Respiration:
The rate of respiration usually doubles as per the Van’t Hoff’s law with increase in tem-
perature by 10 °C in case of poikilothermic animals
Fire Fire is an exothermic factor caused due to the chemical process of combustion,
releasing heat and light. It is mostly man-made and some-times develop naturally due
to the friction between the tree surfaces. Fire is generally divided into the following
types.
1. Ground fire – Which is flameless and subterranean. which develop in such
conditions where organic matter (litter) accumulates richly as heaps and they
catch fire
2. Surface fire – Which consumes the herbs and shrubs. which sweep over the
ground surface rapidly and their flames consume the litter, living herbaceous
vegetation and shrubs and also scorching the tree bases if comes in contact
3. Crown fire – Which burns the forest canopy. which are most destructive,
burning the forest canopy and are common in dense woody vegetations
Effects of Fire
Fire has direct (e.g., lethal) as well as indirect effects on plants and wild-life. Some well
Confirmed indirect effects of fire on plants are as follows:
Effect on plant the ecological factor fire can effect plant on many ways which are
bellow
➢ Germination Many plants depend on fire to heat and scar their seeds as a
process for germination.

30. 30
➢ Nutrient, Decaying trees release nutrients into the soil and serve as a base for
new plants to sprout. Much of the plant life in the United States has evolved to
use fire directly as a catalyst for reproduction or benefited by the nourishment
left in its path
➢ Injury Fire causes injury to some plants, resulting large scars on their stems.
Such scars may serve as suitable avenues of entry of parasitic fungi and insects.
➢ Succession, Fire arrests the course of succession and modifies the edaphic
environment very much.
➢ changes in eco factors Fire brings about distinct changes of such ecofactors as
light, rainfall, nutrient cycles, and fertility of soil, litter and humus contents of
soil, pH, water holding capacity.
➢ Survive competition, Fire plays an important role in the removal of competition
for surviving species. Fire tolerant plant species generally increase in abundance
at the expense of those killed by fire (fire-sensitive plants) due to considerable
reduction in competition and possibly due to alteration in other conditions
Effect on soil fauna some fungi which grow in soil of burnt areas called pyrophilous
Soil fungi are reduced while bacteria increase due to post-fire changes in the soil. The
microclimate too is greatly changed due to addition of ash, loss of shade, loss of
raindrop interception, accelerated erosion, etc.
.
Effect on animals - The specific effects of fire on animals depends on what kind of fire,
the type of vegetation, and the individual animal.
➢ Survive Larger animals generally survive more often than smaller ones;
although a burrowed animal can escape burning, usually it suffocates in the
meantime.
➢ NEST Many birds also thrive after a fire when the seeds of many trees are
dispersed. Birds, like woodpeckers, take advantage of burned out trees to make
nests or forage for dead insects.

31. 31
➢ Insects usually do not survive fires well because their escape range is too small.
This can affect birds if the specific insects are a food source for the aviators.
Trees can benefit from the death of insects that reside in their trunks. Many
insects, in this case the mountain pine beetle in lodgepole forests, kill the trees in
which they inhabit. A lot of these forest pests, like the beetle, or the spruce bud
worm, which resides in Douglas and subalpine fir forests, are burned out by
fires.
Unite 2
Global Ecosystem
Ecosystem; the interaction between living and non-living thing is called ecosystem
History of Ecosystem; the term ecosystem was first used in 1935 in a publication by
British ecologist Arthur Tansley.
Classification of Ecosystem; Ecosystems can generally be classified into two classes
such as
1. Natural and
2. Artificial.
Artificial ecosystems are natural regions affected by man’s interferences. They are
artificial lakes, reservoirs, townships, and cities.
Natural ecosystems are basically classified into two major types.
They are aquatic ecosystem and terrestrial ecosystem

32. 32
Components of ecosystems
There two component of ecosystem which are below
Biotic (Living Components)
Biotic components in ecosystems include organisms such as plants, animals, and
micro-organisms. The biotic components of ecosystem comprise,
• Producers or Autotrophs
• Consumers or Heterotrophs
• Decomposers or Detritus/Scavenger/Cleaner
(A) Producers: The green plants have chlorophyll with the help of which they trap solar
energy and change it into chemical energy of carbohydrates using simple inorganic
compounds namely water and carbon dioxide. This process is known as
photosynthesis. As the green plants manufacture their own food they are known as
Autotrophs (i.e. auto = self, trophos = feeder) the chemical energy stored by the
producers is utilized partly by the producers for their own growth and survival and the
remaining is stored in the plant parts for their future use.

33. 33
(B) Consumers: The animals lack chlorophyll and are unable to synthesize their own
food. Therefor, they depend on the producers for their food. They are known as
heterotrophs (i.e. heteros = other, trophos = feeder) the consumers are of four types,
namely
(a) Primary Consumers or First Order Consumers or Herbivores:
These are the animals which feed on plants or the producers. They are called
herbivores. Examples are rabbit, deer, goat, cattle etc.
(b) Secondary Consumers or Second Order Consumers or Primary Carnivores:
The animals which feed on the herbivores are called the primary carnivores.
Examples are cats, foxes, snakes etc.
(c) Tertiary Consumers or Third Order Consumers: secondary Carnivores
These are the large carnivores which feed on the secondary consumers. Example
are Wolves. Lions and tigers
(d) Quaternary Consumers or Fourth Order Consumers or Omnivores:
These are the largest animals which feed on producer and primary consumers
and are not eaten up by any other animal. Examples are man, apes and crow.
(C) Decomposers or Reducers:
The decomposers are known as Saprotrophs (i.e., sapros = rotten, trophos =
feeder) Bacteria and fungi are responsible for the breakdown of the dead organic
materials of producers (plants) and consumers (animals) for their food and
re•lease to the environment the simple inorganic and organic substances
produced as by-products of their metabolisms. These simple substances are
reused by the producers resulting in a cyclic ex•change of materials between the
biotic community and the abiotic environment of the ecosystem.

34. 34
Abiotic Components:
The nonliving factors or the physical environment prevailing in an ecosystem form the
abiotic components. They have a strong influence on the structure, distribution,
behavior and inter-relationship of organisms.
Abiotic components are mainly of two types:
(a) Climatic Factors:
Which include rain, temperature, light, wind, humidity etc.
(b) Edaphic Factors:
Which include soil, pH, topography minerals etc.?
(a) Climatic factors consist of Temperature, rainfall and snow, wind, light, humidity
etc. The climate of an area is the result of several factors such as latitude, elevation,
nearness to the sea, and monsoon activities and ocean currents.
Temperature influences the rates of biochemical reactions in plants, with the reaction
rates approximately doubling with every 10°C increase. Plant species require a range of
temperature to survive. Below a minimum temperature they are inactive, and above a
maximum temperature biochemical reactions stop. Normally in many plants growth is

35. 35
possible above 6°C. In areas with extremes of temperature, such as the tundra and
tropical deserts the plants have mechanisms to adapt to such conditions.
Light levels decide the magnitude of photosynthesis reactions. Different plants have
their characteristic light requirements in respect of light intensity, duration and
wavelength. Some plants, termed heliophytes, require high levels, whereas sciophytes
can grow in shady, low light conditions.
Water is an essential factor for biochemical plant processes, including photosynthesis.
Plants growing on lands obtain their water requirements from the soil through their
roots by the osmosis process. Plants called Hydrophytes grow in fresh water and they
cannot withstand drought. Xerophytes (desert plant) survive long periods of drought,
and halophytes are able to survive in saline water. Mesophytes require moderate
conditions (neither waterlogged nor drought) and are found mainly in temperate areas.
(b) Edaphic factors or soil factors are pH, mineral and organic matter in soil and
texture of soil.
Soil is the major source of nutrients and moisture in almost all the land ecosystems. Soil
is formed when a rock weathers .The rocks brake down into a collection of different
inorganic or mineral particles. The climate influences the type and rate of the
weathering of the rocks as well as the nature of the vegetation growing on it. Nutrients
are recycled in the soil by the plants and animals in their life cycles of growth, death
and decomposition. Thus humus material essential to soil fertility is produced.
Soil mineral matter is derived from the weathering of rock material. These consist of
two types viz. stable primary materials like quartz and various secondary materials like
clays and oxides of Al and Fe.
Soil texture is the different size range of mineral particles varying from fine clay to
coarse gravel. The varying percentages of each size range produce soils with different
characteristics.
Soil organic matter is called humus that is formed by the decomposition of plant and

36. 36
animal matter. The rate of decay depends upon the nature of the material and the
climate. The humus produced and incorporated into the soil, is known as clay-humus
complexes, which are important soil nutrients.
Soil organisms carry out following three main groups of processes.
The Decomposition of organic material(such as plant and animal parts) by bacteria,
fungi and earthworm.
Bacteria and fungi also breakdown soil mineral matter generating nutrients.
Transformation and fixation of Nitrogen (which is an essential plant nutrient) obtained
through rainwater or from nitrogen gas in the air. Bacteria like Azobacter and
Rhizobium in the root nodules of leguminous plants, fix nitrogen from the air. Some
types of bacteria have the ability to transform pesticides and herbicides into less toxic
compounds.
Biomes are large areas on Earth with similar conditions, such as similar climates and
similar living organisms. There are two main categories of biomes.
Terrestrial biomes are usually defined by the type of vegetation that is present. The
major climatic factors contributing to the vegetation types in these biomes are
temperature and precipitation.
Aquatic biomes are defined by the type of water they contain.
Some of the major biomes of the world are as follows:
1. Desert Biome 2. Grassland Biome 3. Rain Forest Biome 4. Deciduous Forest
Biome 5. Taiga Biome 6. Tundra Biome.
1. Desert Biome:
A desert usually has less than 25 cm of rain per year. Deserts are also characterized
by intense sunshine and very hot days (40°C and upward) at least during summer;
and the evaporation rate is very high. Nights are generally cold, even in summers,
and daily variations in temperature reach extremes found in no other environment.
Desert life is usually well adapted to the dry weather.

37. 37
Most annual plants in the desert are small. They grow rapidly, bloom and produce
seeds all within a few days after a rain. Since the growing season is greatly
restricted, such plants live relatively small. Many perennial desert plants have small
leaves, or none at all, or their leaf surfaces are often reduced to spines and thorns,
minimizing water loss by evaporation. Some have very long roots, reaching deeply
buried water. Others, like the cacti, absorb water rapidly after a rain and store the
same in spongy internal tissues.
Desert animals are also adapted to scarcity of water and extremes of temperature. In
most deserts, the large homoeothermic mammals and birds are comparatively rare
or are absent altogether because the maintenance of a constant body temperature is
difficult or rather impossible under conditions of extreme heat and practically no
water.
However, some animals like the camel are adapted to extreme desert conditions.
Animals, which match their internal temperature to that of their environment, the
so-called cold-blooded animals, live more easily in the desert. Desert animals are
generally small, and they include many burrowing forms, which may avoid the
direct heat of the Sun. In all deserts small rodents are numerous and almost all are
burrowers. The kangaroo rat (Dipodomys) is a desert animal depending on bipedal,
leaping locomotion. Snakes and lizards are common in all deserts.
2. Grassland Biome:
In a grassland biome, the vegetation is dominated by grasses, which may grow to
about 2 m in the moist areas and 0.2 m in arid regions of the grassland biome. It is
not an exclusively tropical biome but extends into much of the temperate zone as
well. The more or less synonymous terms “prairie” (in North America), “pampas”
(South America), “steppes” (in Central Asia) “puszta” (Hungary) and many other
regional terms underscore the wide distribution of this biome.
The common feature of all grasslands is irregular, unpredictable rainfall, amounting
to about 4 to 16 cm annually. The irregularly of rain, porosity and drainage of the
soil, or both factors together prevent a continuous or ample supply of water to plant

38. 38
roots. Grasses of various kinds are particularly adapted to irregularly alternating
periods of precipitation and dryness. The environmental conditions vary greatly in
different grasslands. There are also non-grass herbaceous species, which are called
forbs.
Grassland biome probably supports more species of animals than any other
terrestrial habitat. In all grasslands, the primary consumers are the large grazing
mammals like the bisons, pronghoms (Antilocapra Americana ) and zebra (Equus
zebra). African glass-lands support large herds of zebras and several species of
grazing antelopes.
The grassland ungulates are cursorial (fitted for running). Hares and rodent are also
common primary consumers in the grasslands. Many rodents, like the prairie dogs
and other ground squirrels or the pocket gophers, are burrowing or fossorial
animals. Australian grasslands have herbivores very different in appearance and
relationships but ecologically similar.
These are large grazing cursorial kangaroos and small, burrowing, rodent-like
pouched “mice”. Predators are adapted to the herbivore prey: wild dogs, lions, and
the like preying on the ungulates; weasels, snakes, and others on the smaller
herbivores. Herbivorous insects such as locusts and grasshoppers are also
numerous. Grasslands also support some herbivorous predacious birds.
Rain Forest Biome:
They occur in those tropical and subtropical parts where heavy rains fall practically
every day and where a well-defined rainy season characterizes the winter. Rain
forests exhibit a communal coexistence of up to several hundred different species of
trees. They cover much of Central Africa, South and Southeast Asia, Central
America, and South America.
However, in contrast to rain forests in the tropics, the species diversity of temperate
rain forests is quite low. A tropical rain forest generally has a hundred or more
species of trees, and as many as 500 have been observed m one such forest. Two
trees of the same species seldom stand near each other. However, the actual species

39. 39
present may be totally different in rain forests found in widely separated regions of
the earth.
Tropical rain forest biome receives about 200 cm of precipitation during a year. The
productivity of this biome is more than that of any other terrestrial biome. Because
of high temperature and abundant moisture, plant litter decomposes quickly and the
vegetation immediately takes up the nutrients released. A striking feature of a
tropical rain forest is the vertical stratification of plant communities.
Trees in such forests are normally so crowded together that they form a continuous
overhead canopy of branches and foliage, which cuts off practically all the sunlight,
much of the rain water and wind. As a result, the forest floor is very humid and
quite dark and, therefore, plants that require only a minimum of light populate it.
Apart from the forest trees themselves climbing Lianas and Epiphytes are quite
characteristic of the tropical rain forests. Rooted in the dark forest floor, lianas are
climbing vines, which use the standing trees as supports upon which they climb
toward the canopy where they spread their leaves in the light. Epiphytes grow on
other plants. Orchids, ferns, and many other epiphytes form veritable aerial gardens
among the high branches of the trees of rain forests.
Trees in such forests are normally so crowded together that they form a continuous
overhead canopy of branches and foliage, which cuts off practically all the sunlight,
much of the rain water and wind. As a result, the forest floor is very humid and
quite dark and, therefore, plants that require only a minimum of light populate it.
Apart from the forest trees themselves climbing Lianas and Epiphytes are quite
characteristic of the tropical rain forests. Rooted in the dark forest floor, lianas are
climbing vines, which use the standing trees as supports upon which they climb
toward the canopy where they spread their leaves in the light. Epiphytes grow on
other plants. Orchids, ferns, and many other epiphytes form veritable aerial gardens
among the high branches of the trees of rain forests.
In rain forests animal communities too are stratified vertically into different habitats
found between canopy and ground. A much larger proportion of animals live in the

40. 40
upper layers of the vegetation than in temperate forests where most of the life is
near the ground level. For example, 31 to 59 species of mammals in British Guiana
are arboreal and 5 are amphibious, leaving only 23, which live on the ground.
In addition to the arboreal mammals (monkeys, rodents, squirrels), there is an
abundance of chameleons, iguanas, geckos, arboreal snakes, frogs, and birds. Ants,
termites, beetles and the Orthopetra, as well as butterflies and moths are ecologically
important. Frogs may be present in large numbers.
In the Old World rain forests, ground-dwelling herbivores include musk deer, small
forest antelopes, and forest pigs. In both hemispheres partly arboreal carnivores,
especially cats such as leopard and jaguar, kill the herbivores. Symbiosis between
animals and epiphytes is widespread. Many animals of the rain forest are nocturnal.
Deciduous Forest Biome:
In the temperate zones such as Europe, eastern Asia, southern Canada and eastern
part of United States, the most characteristic biome is the deciduous forest. Tropical
deciduous forests also occur in many tropical parts of the world. The fundamental
climatic conditions of a deciduous forest biome are cold winters, warm summers,
and well spaced rains bringing about 75 to 100 cm of precipitation per year. The
biome is also characterized by seasonal temperature variations, which are greater
than daily variations.
Winter makes the growing season discontinuous, and the flora is adapted to this.
The temperate deciduous forests cover many parts of the United States, the British
Isles, Central Europe, China and south-eastern Siberia. Similar forests also occur in
the Temperate Zone of South America, but they are not so widespread there.
The term “deciduous” implies the most obvious characteristic of this biome and the
most obvious adaptation to it (i.e., trees shed their leaves and hibernate). Half the
year or somewhat more is the growing season, when perennial plants put on their
leaves and are active, while annual plants go through the whole cycle from seed to
seed.

41. 41
The rest of the year the trees are bare. Common trees of the deciduous forest are
beech, tulip, sycamore, maple, oak, hickory, elm, poplar, and birch. Chestnuts were
also formerly common. A deciduous forest differs from a rain forest in that trees are
spaced at considerable distance from one another and there are only few species of
trees. Compared with the hundreds of tree species in a rain forest, there may be only
about 10 or 20 in a deciduous forest.
The most striking herbivorous mammals of a deciduous forest are the browsing
deer, mainly the white-tailed deer in North America and other species in Eurasia
and South America. In Eurasia wild pigs (or boars) are also found in this biome, but
they do not occur native in America. The principal carnivores are the large cats
including puma, mountain lion, cougar, or panther (all one species, Felis concolor)
ranging into most of the environments of North and South America. Foxes are also
common in them.
The arboreal martens are locally as common here as in the taiga, and the raccoon
(absent in Eurasia) is especially abundant in deciduous forests of North America.
Throughout the world these forests are also rich in tree squirrels. Among mammals
of the North American deciduous forests, over a third of the species are mainly
arboreal. Tree-nesting birds are also abundant and woodpeckers are characteristic of
this biome. The leaf and mold-covered forest floor supports many species of
invertebrates and fungi
Tundra Biome:
In Asia, Europe, and North America a vast northern zone encircling the Arctic
Ocean is known as the tundra. This biome lies north of the taiga. The tundra has the
arctic climate, which is cold, and there may be continuous night during the winter
season and continuous daylight, of comparatively low intensity, during the summer.
Some distance below the surface, the ground is permanently frozen.
This is called permafrost (is any ground that remains completely frozen). Above
the ground, frost can form even during the summer; plants often freeze solid and
remain dormant up to the growing season. The latter is very brief, as in the deserts;

42. 42
but in the tundra the chief limiting factor is temperature, and not water supply.
However, alpine tundra does not contain permafrost.
Taiga Biome:
North of the deciduous forests and the grasslands across northern Europe, Siberia,
and Canada, stretches the taiga (northern coniferous forest biome). It is also called
the boreal forest(snow forest) biome. This is a biome of long, severe winters and of
growing seasons limited largely to the few months of summer. The vegetation is
extremely frost-tolerant, as temperatures may fall to – 60° C during the winter. The
precipitation is in the range of 40-100 cm. Hardy conifers, spruce in particular, are
most representative of the flora; and moose, wolves, and bears of the fauna.
The taiga is largely a zone of forests, which differ from other types of forests in that
they usually consist of single species of coniferous tree. Thus, over a large area,
spruce, for example, may be the only kind of tree present. Among other coniferous
trees, alder, birch, and juniper thickets are common. They might be found in an
adjacent equally large area. Many of the larger herbivorous vertebrates, such as the
moose (elk), snowshoe hare, and grouse depend on broad leaved developmental
communities of spruce forest.
The seeds of conifers provide important food for many animals such as squirrels,
siskins, and crossbills. In taiga, seasonal periodicity is pronounced and populations
tend to oscillate. The snowshoe hare-lynx cycles are classic examples. Smaller
mammals are much more varied than in the tundra. Black bears, wolves, and
martens are more common in this biome that elsewhere.
Fishers, wolverines, lynex and some rodents such as the northern vole are practically
confined to it. Squirrels and birds also thrive in coniferous forests. Most of the birds
here, however, are summer breeders and migrate southward in the autumn. The
many species of insects remain dormant during the severe winters
Precipitation is generally less than 50-60 cm but in low lying areas soils may remain
saturated with water during most of the growing season. Plants are low, ground
hugging forms, and frees are absent. Lichens (especially reindeer moss), mosses

43. 43
(especially Sphagnum) coniferous and other shrubby growths, and herbs with
brilliantly coloured flowers, are characteristic of the habitat.
The warm-blooded animals of this biome are caribou, reindeer, musk ox, arctic hare,
arctic fox, lemming, and polar bear. They are well protected by fur. Some of the
resident birds, like the ptarmigan (an arctic grouse-like bird), and mammals, like the
snowshoe hare, turn white in winter. White is protective colouration in a snowy
environment and also minimizes heat loss by radiation. Musk oxen and caribou
(wild reindeer) are large herbivores, which depend mainly on the abundant moss
and lichens. Arctic hares and lemmings (small, rat-like rodents) are numerous and
are preyed on by arctic foxes.
Polar bears are amphibious, frequenting coasts and ice flows but also wandering
inland on the tundra. Insects, especially flies, are so numerous as to be one of the
major drawbacks of the tundra from the human point of view. Their eggs and larvae
are particularly cold resistant and the adults appear by the billions on warmer
summer days.
Migratory birds, especially waterfowl, are conspicuous during the short summer.
Well marked oscillations, or cycles, in population density of some animals are
characteristic of tundra communities. For example, when lemmings abound,
predatory birds, such as owls are abundant and breed. Whereas few predators breed
at all during the years of prey scarcity.
However, the life does not end at the northern margin of the tundra but extends
farther into the ice and bleak rock of the soilless polar region. Polar life is almost
exclusively animal, and it is not really terrestrial in any way but is based on the sea
{e.g. walrus, seals, penguins).
However, some authors also describe the so-called alpine tundra biome. This occurs
above the tree line as in the Rocky Mountains of North America and on the Tibetan
Plateau of Central Asia. The alpine and arctic tundra have some similarities as well
as differences. Alpine tundra does not contain permafrost; it has warmer and longer

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growing seasons resulting in higher productivity, less severe winters, and higher
species diversity than arctic tundra.
Unite
Pollution?
Pollution is an undesirable change in the physical, chemical or biological characteristics
of our air, land, and water that may or will harmfully affects human life or that of
desirable species,
POLLUTANTS: THE CREATORS OF POLLUTION
Every human society, be it rural, urban, industrial and most technologically advanced
society,
Dispose of certain kinds of byproducts and waste products which when are injected
into the biosphere in quantities so great that they affect the normal functioning of
ecosystems and have an adverse effect on plants, animals, and man are collectively
called pollutants.
A pollutant is a constituent in the wrong amount, at the wrong place or at the wrong
time. For example, nitrogen and phosphorus are essential nutrients for living organisms
and are extensively used in agriculture to increase crop yields but they can also cause
pollution in lakes and rivers when found in excess by promoting undue algal growth
(eutrophication
Types of Pollutants
Pollutants primarily are grouped into the following two types:
1. Natural pollutants. Certain pollutants such as carbon dioxide, carbon monoxide,
sulphur dioxide, lead, mercury and other trace elements are the consequence of life
processes being produced through respiration, faeces, urine and body decomposition.
With an increase in human population, the pollutants are increasing with alarming rate.
2. Synthetic, man-made, anthropogenic or xenobiotic pollutants.
A vast array of synthetic pollutants are increasing continuously with urbanization and
industrial growth. They include pesticides, detergents, pharmaceuticals, cosmetic

45. 45
products, organic acids, aerosols, and metals, etc. Several of these compounds are
extremely stable and persist in the environment for a considerable period
posing serious environmental hazards.
From the ecosystem viewpoint, these pollutants can be classified into two basic types:
Non-degradable pollutants and biodegradable pollutants The materials and poisons,
such as aluminum cans, mercurial salts, long-chain phenolic chemicals and DDT that
either do not degrade or degrade only very slowly in the natural environment, are
called non-degradable pollutants. Such non-degradable pollutants not only accumulate
but are often “biologically magnified” as they move in biogeochemical cycles and along
food chains. Also they frequently combine with other Compound in the environment to
produce additional toxins.
Biodegradable pollutants include domestic sewage, heat, etc. The domestic sewage
can be rapidly decomposed by natural processes or in engineered systems (such as a
municipal sewage treatment plant) that enhance nature’s great capacity to decompose
and recycle. Problems arise with the biodegradable pollutants when their input into the
environment exceeds the decomposition or dispersal capacity.
Types of Pollution
There are several types of pollution, and while they may come from different sources
and have different consequences, understanding the basics about pollution can help
environmentally conscious individuals minimize their contribution to these dangers. In
total, there are nine recognized sources of pollution in the modern world. These sources
of pollution don't simply have a negative impact on the natural world, but they can
have a measurable effect on the health of human beings as well.
Different Types of Pollution
Different Types of pollution are categorized based on the part of the environment
which they affect or result which the particular pollution causes. Each of these types
has its own distinctive causes and consequences. the main types of pollution are:

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2. WATER POLLUTION
.
water pollution is referred to any type of aquatic contamination between following two
extremes:
(1) A highly enriched, over productive biotic community, such as a river or lake with
nutrients from sewage or fertilizer (cultural eutrophication),
(2) A body of water poisoned by toxic chemicals which eliminate living organisms or
even exclude all forms of life
Normally water contains two types of impurities-
(1) Dissolved
(2)Suspended.
(1) Dissolved impurities are gases (H2S, CO2, NH3, etc.) and minerals (Ca, Mg, Na,
salts).
(2) Suspended matter includes clay, silt and sand and even microbes. Polluted waters
are turbid, unpleasant, foul smelling, unfit for drinking, bathing and washing or
other purposes. They are harmful and means of many diseases as cholera,
dysentery, typhoid, hepatitis, etc.
Water pollution can occur from two sources. 1. Point source/direct and 2. Non-
point source/indirect
Some of the important sources of Point source/direct of water pollution are:
(i) Domestic effluents and sewage,
(ii) Industrial effluents,

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(iii) Agricultural effluents, ,
(iv) Thermal pollution, and
(v) Oil pollution
Air pollution
It is defined as the undesirable contamination of gas, smoke, dust, fume, mist, odour, or
Chemical particulates in the atmosphere which are injurious to human being, plants
and animals
Causes of air pollution the causes of air pollution are;
1. Industrialization
2. Urbanization
3. Vehicles emission
4. Deforestation
5. Population
.
Types of air pollutants
Air pollutants can broadly classified into two types-
1 Primary pollutant
2. Secondary pollutants
(1) Primary pollutants
Pollutants that are emitted directly from either natural events or from human activities
are called primary pollutants. The natural events are dust storms; volcano e.t.c and
human activities can be emission from vehicles, industrial wastes. About 90% of global
air pollution is constituted by five primary pollutants. These are
1. Carbon oxides (CO and CO2)

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2. Nitrogen oxides
3. Sulphur oxides
4. Hydrocarbons
5. Particulate matter
(2) Secondary pollutants.
Primary pollutants when reacting with each other or from basic components of air;
forms a new pollutants called secondary pollutant. For example sulphuric acid, nitric
acid, carbonic acid, etc.
Types of Air pollutant, The major types of air pollutant are;
1. Carbon monoxide.
It is a colourles, odorless, flammable gas, which is a product of incomplete
combustion. If carbon were completely oxidized during burning, complete
combustion to carbon dioxide would occur and carbon monoxide would not be a
problem. It is important not to confuse carbon monoxide with carbon dioxide.
Carbon monoxide (CO) is an incomplete combustion product and can be toxic even
at low concentrations, whereas carbon dioxide (CO2) is a complete oxidation
product.
Sources of Carbon monoxide
Carbon monoxide is formed whenever a carbon material is burned e.g. automobile
exhausts, cigarettes etc. In addition to motor vehicles, sources of carbon monoxide
include burning coal, natural gas or biomass. Biomass combustion can be a significant
source of exposure in rural areas or in underdeveloped countries where it is burned for
cooking, heating and even light. Atmospheric oxidation of methane gas and other
hydrocarbons also produces carbon monoxide.

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Effects of CO
Carbon monoxide accounts for more than 50% of air pollution nationwide and
worldwide. It is a Universal pollutant, Worldwide and hundreds of millions monoxide-
related illness, which include Headache, dizziness and drowsiness. Reports show that
about 11% heart failure caused by excess carbon monoxide.
In the normal situation, the iron atom in the blood protein haemoglobin, picks up
oxygen from the lung and transports in to the body’s cells. There the haemoglobin
releases oxygen and picks up the waste gas carbon dioxide, which it transports back to
the lungs and releases. After releasing carbon dioxide, it picks up more oxygen. Carbon
monoxide has 200 items greater affinity for the iron in haemoglobin than doe’s oxygen
and interrupts this cycle by displacing oxygen. The result is a lowered amount of
oxygen reaching the heart which can lead to heart failure in sensitive people. Carbon
monoxide also has other adverse effects in the body. For example, it interferes with the
oxygen-carrying proteins in muscles. When humans are exposed to CO, it forms
carboxy haemoglobin at the expense of oxyhaemoglobin. Tissues are thus deprived of
oxygen and suffocation occurs. If the victim continues to receive a high dosage of CO,
then permanent brain damage and even death will result. Initial symptoms include
dizziness, headache, nausea and faintness. Chronic exposure at 25 mg m-3 of CO in air
causes cardiovascular problems which can be particularly dangerous to a person who
already suffers from such problems. The inhalation of 35 ppm CO for eight hour causes
a loss in ability to learn and do complicated tasks,reduces awareness, decreases manual
skill, and disturb sleep activity.
Measures to reduce carbon monoxide

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About half of the motor vehicle carbon monoxide emissions in our country are
produced by only 10% of the vehicles. Efforts are being made to find and remove these
vehicles from road. Car and truck owners need to maintain their vehicles. Other
measures to control carbon monoxide emissions include facilities that burn fossil fuels
or wood to maintain high burning efficiencies and prohibiting open burning trash and
garbage.
2. Sulphur dioxide
Sulphur dioxide (SO2) is a Colourless gas with a sharp odour that accounts for about
18% of all air pollution.
Sources: Chemical industries, Metals meltings, Pulp and paper mills, Oil refineries
Effects of Sulphur dioxide
Sulphur dioxide reacts with moisture in eyes, lungs and mucous membranes to form
strong irritating acid. It can trigger allergic reaction and asthama. If moisture is present
in the atmosphere, sulphur dioxides are converted into sulphuric acid or if conditions
are dry, into sulphate particulates. The tiny- only 0.1 to 1 mm in diameter-sulphuric
acid and sulphate particulates form aerosols. The aerosols contribute to the adverse
healths effects of smog and haze and also play a serious role in haze. Sulphuric acid and
sulphate are likewise directly involved in three serious global change problems. Acidic
deposition is one of those. The sulphate particles accumulate in the stratosphere zone
provide surfaces on which ozone-destroying reactions occur. A third major effect is the
anti-warming influence they exert in global climate change.
3. Nitrogen dioxide

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Nitrogen dioxide is a reddish brown irritating gas. They account for about 6% of
pollution. Sources of nitrogen dioxide: Motor vehicle exhausts, Gasoline Volcanoes,
Lightning effect lungs
4. Lead
Lead a highly useful metal has been mined for thousands of years. And it has been
known for thousands of years that lead is toxic to the nervous system. The level lead in
modern human skeletons and teeth is at least a hundred-fold greater than the level
found in pre-industrial age skeletons. The combustion of alkyl lead additives in motor
fuels accounts for major part of all lead emission into the atmosphere. An estimated 80-
90 percent of lead in ambient air derives from the combustion of leaded petrol. The
degree of pollution from this source differs from country to country depending on
motor vehicle density and the efficiency of effort to reduce the lead content of petrol.
The mining and smeltering of lead ores create pollution problems in some areas.
Children up to 6 years of age are a population at increased risk for lead exposure as
well as for adverse health effects as children have behavior lead exposure as well as
adverse health effects as children have behavior characteristics which increase the risk
of lead exposure, the blood-brain barrier is not yet fully developed in young children
and hematological and neurological effects of lead occur at lower threshold in children
than in adults.
5. Particulate Matter
Particular matter is defined as single particles or aggregates of particles with diameters
greater than 2x10-10 m. some particulate matter is natural i.e. rain, snow, fog, hail and
mist, while others are often the result of human processes, e.g. smoke, soot and fumes.

52. 52
Some natural particulates are affected by human actions such as fog and wind-blown
soils. Smoke and soot are the products of incomplete combustions of coal, petrol and
diesel fuels in furnaces, domestic heating systems and vehicle engines.
Effects of particulate it causes the following.
Aerosols are mixture of minute solid or liquid particles suspended in air that from a
haze or spoil visibility. The main problem to humans caused by atmospheric
particulate matter is how far it is able to penetrate the respiratory system. Particles in
the size range 30x10-6 to 100x10-6 m lodge in the nasal cavity, larynx and trachea. Some
examples of particles of this size are pollen, fungal spores, cement dust and coal dust.
Particles less than 15x10-6 m find their way into the bronchus and bronchioles e.g.
tobacco, smoke and fumes. particles of 4x10-6 m and less can enter alveoli where
gaseous exchange take place between the blood stream and air e.g. asbestos dust, glass
and viruses. Particulate matter comes from two major sources.
(a) Primary particulates
First, those emissions that comes directly from sources such as coal combustion, wind-
blown dust and quarrying. These are called primary particulates.
(b)Secondary particulates
Other particulars can be formed from chemical reactions between pollutant gases
such as sulphur dioxide, the oxides of nitrogen and ammonia such reactions lead to the
formation of solid sulpahte and nitration’s. Organic aerosols may also be formed by the
oxidation of volatile organic compounds. These particulates are termed as secondary
particulates are termed as secondary particulates.
TECHNIQUE TO REDUCED AIR POLLUTION
There are different ways to reduced outdoor and indoor pollution which are bellow.
OUT DOOR. The outdoors pollution can be reduced by the following measurement.
1. Minimize air pollution from cars. The greatest contributor to air pollution is the
automobile. Each year, motor vehicles emit about 1,000 tons of toxic and carcinogen
compounds into the air. The average vehicle emits about a half a ton of air pollution
each year. Most car pollutants come from the exhaust but brake pads, tires, oil, grease,

53. 53
anti-freeze, hydraulic fluids, and cleaning agents also contribute pollutants to the
environment. As you may know, several steps have been taken over the last 20 years to
improve the emissions from automobiles nationwide.
2. Walk, use bike or public transportation driving cars contributes to traffic congestion,
air pollution, and the risk of injury and death to road users, whereas walking and
cycling pose little risk to others and provide opportunities for physical activity we also
achieve and reduced air pollution through changes in the transport environment.
3. Save energy. Energy conservation effort made to reduce the consumption of
energy by using less of an energy service Energy conservation reduces the need for
energy services and can result in increased environmental quality.
4. Maintain your wood stove or fireplace
Select a stove that is certified clean-burning and tested.
• Make sure wood-burning equipment is properly installed, inspected,
and maintained
• Avoid smoldering fires
• Reduce the need for fuel: make your home more energy efficient by properly
weatherizing it
5. Recycle & buy recycled products Recycling is a process of turning waste into new
material or product buying the products that are made of recycled material. Paper and
plastic are some examples of recycled products.
6. Grow your own food growing your own food has many health benefits:
It helps you eat more fresh fruits and vegetables. You decide what kinds of fertilizers
and pesticides come in contact with your food. It also reduces air pollution.
7. Plant trees, trees are an important, cost-effective solution to reducing pollution and
improving air quality In Pakistan air pollution contributes to 50 per cent of premature
mortalities. It can be reduced with native trees if these are planted in the City limits and
in houses. Plant absorb gaseous air pollution. Ground-level ozone formation is reduced
because air temperatures in tree-filled areas are cooler. Plant is the factory of oxygen
which is important for animal life as well as ozone layer.

54. 54
6. Eat local, organic produce: Local food is harvested when ripe and thus fresher and
full of flavor. Organic food is often fresher because it doesn’t contain preservatives that
make it last longer. Organic produce is often produced on smaller farms near where it
is sold. Organic farming is better for the environment. Organic farming practices reduce
pollution, conserve water, reduce soil erosion, increase soil fertility, and use less energy.
Farming without pesticides is also better for nearby birds and animals as well as people
who live close to farms. Organically raised animals are not given antibiotics, growth
hormones, or fed animal byproducts. Feeding livestock animal byproducts increases the
risk of mad cow disease and the use of antibiotics can create antibiotic-resistant strains
of bacteria. Organically-raised animals are given more space to move around and
access to the outdoors, which help to keep them healthy Organic meat and milk is richer
in certain nutrients. Result of a 2016 European study shows that levels of certain
nutrients, including omega-3 fatty acids, were up to 50 percent higher in organic meat
and milk than in conventionally raised versions.
1. Raise awareness
• Tell your friends and family about air pollution.
• Encourage your parents to carpool to work
• Arrange walk.
• Arrange seminar and symposium.
• Delivered lecture on print and electronic media.
INDOORS; the indoors pollution can be eliminated by the following measurement.
(1)Keep air-purifying indoor plants
Living in an energy efficient, modern building can have unintended side effects. One of
these side effects is less air flow. Lack of air flow allows for indoor air pollution to build
up and cause health issues like asthma or sick building syndrome. In fact, modern
furnishings, synthetic building materials, and even your own carpet may carry more
chemicals than expected. These chemicals can make up to 90 percent of indoor air
pollution. You may want to reconsider air-purifying plants if you have pets such as cats

55. 55
and dogs. Many of these plants can be toxic to them. An increase in plants can also
affect humidity and promote mold growth. You can prevent this by letting the water
drain into a pan or a tray, removing excess water regularly.
2. Open windows. Adequate ventilation is key,s to promoting healthy indoor air, and
opening windows (when it's not too cold or the pollen count is not too high, of course)
is an easy way to encourage a good exchange of indoor and outdoor air.
3. Use essential oils
Constant use of air conditioners and pollutants in the air outside can damage the air
indoors as well. Using eucalyptus oil as a diffuser at home can help in disinfecting
indoors, making the indoor environment cleaner and less polluted.
(4) Test your home for radon;
Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive,
colorless, odorless, tasteless noble gas. Radon comes naturally from rocks and dirt in the
ground. There’s always some radon in the air around us. The problem is when radon
gas from underneath a home leaks in through cracks or gaps. Too much of it can build
up inside. When you breathe in radon gas, the radioactive particles can get trapped in
your lungs. Over time, they can cause lung cancer.
(5) Do not smoke indoors
Making your home smoke-free may be one of the most important things you can do for
the health of your family. Any family member can develop health problems related to
smoking. Children’s growing bodies are especially sensitive to the toxins. And think
about it: we spend more time at home than anywhere else. A smoke-free home protects
your family, your guests, and even your pets
(6)Keep indoor humidity low higher humidity does decrease your energy efficiency. It
makes the air inside your home warmer
• Run Exhaust Fans in the House, kitchen and bathroom exhaust fans are there for
a reason – to help let out obnoxious odors and excess humidity.

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• Grow Plants that Absorb Humidity Some plants, Not only reducing your
humidity levels and energy consumption but helping the environment by
removing more carbon dioxide and adding more oxygen too!
• Replace Your Carpet carpets also have the ability to retain moisture. Because of
this, they may be quietly contributing to the humidity of your home. In the event
you have tried other methods of dehumidifying your house and they have not
worked, you may want to consider replacing the carpet.
(7) Clean dust,
Remove heavy dust from ceiling, floor, or appliance vents with a soft-brush, vacuum
attachment or electrostatic then dampen a microfiber cloth and wipe the surface. Rinse
removable, washable air-conditioning filters well in hot soapy water and air-dry before
reinstalling.
(8)Use air purifiers An air purifier or air cleaner is a device which removes
contaminants from the air in a room. These devices are commonly marketed as being
beneficial to allergy sufferers and asthmatics, and at reducing or eliminating second-
hand tobacco smoke.
Land/Soil Pollution
Humans and animals used resources that earth could supply for existence for millions
of years. Earth (Land) being natural resources is also used for disposal of the wastes we
generate. Even in the primitive society the hunters and gathers dispose their waste near
and by their caves.
Solid wastes are the wastes arising from human and animal activities that are normally
solid and that are discarded as useless or unwanted. It encompass the heterogeneous
mass of throw away
from mostly urban communities as well as the more homogenous accumulation of
agricultural, industrial and mineral wastes. The problem of solid waste was not as bad
as it is now. In the past, the number of population in urban and rural communities was
not so populated. But, the problem of solid waste began when first humans congregate
in tribes, villages and communities. The practice of throwing waste into the streets,

57. 57
galleries, any where in the yard, and vacant areas led to the breeding of rats and flies.
For example, in Europe because of waste accumulation at the time of formation of
large communities resulted in increment of the rat population. It was during that time
that the great plague pandemic killed hundreds of
thousands of people in the world. Present public health science proved that those rats,
flies and other diseases vector breed in open dumps, in food storage facilities, and in
other areas and houses. One study inUSA revealed that there is 32 human diseases
which have relationship to improper solid waste management.
Ecological impacts of solid waste include:-
a. Water and air pollution.
b. Liquid that seeps from open dumps or poorly engineered landfills will contaminate
surface water and ground water found in the vicinity.
c. In mining areas, the liquid leached from waste dump may contain toxic elements
such as copper, arsenic or may contaminate water supplies from unwanted salts of
calcium and magnesium. Some substances such as DDT, and mercury are relatively
stable; they are non-degradable and insoluble in water. They are neither used nor
eliminated, but are stored in the body, where they may exert a cumulative damaging
effect on a variety of physiological processes For example, DDT is soluble in fat. It tends
to accumulate in the fatty tissues of organisms. For this reason, like mercury, DDT is a
prime candidate for biological concentration. The DDT that becomes concentrated in
tissues of herbivores (such as insects) becomes even more concentrated in tissues of
carnivores that eat quantities of the DDT-harboring herbivores. The concentration
proceeds at each trophic level.
Pesticides
Pesticides are substances, which kill pests and disease vectors of agriculture and public
health importance. Pesticides are sub divided into groups according to target
organisms:
•Insecticides; kill insects
•Rodenticides; kill rats and mice

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•Herbicides; kill weeds
•Nematicides; kill nematodes
Insecticides: the largest numbers of pesticides are employed against a wide variety of
insects, and include: stomach poison (taken into the body through the mouth); contact
poisons (penetrate through the body wall); and fumigants (enter insects through its
breathing pores).
Inorganic insecticides
These insecticides act as stomach poison. Lead arsenate, Paris Green, and a number of
other products containing copper, zinc, mercury, or sulfur are examples of inorganic
insecticides. Many of these products are quite toxic to man as well as to insects.
Botanical Certain plant extracts are very effective contact poisons, providing quick
knockdown of insects. Most botanical preparations are non-toxic to humans, and can be
safely used.
Chlorinated hydrocarbons
These are contact poisons. DDT, chlordane, lindane, endrine, alderin are some of the
chlorinated hydrocarbons. These insecticides are broad-spectrum, and act primarily on
the central nervous system, causing the insect to go through a series of convulsions
prior to death. They are also persistent in the environment, breaking down very
slowly, and therefore, retaining their effectiveness for a relatively long period after
application.
Organophosphates
Organophosphate are broad-spectrum contact poisons. Unlike chlorinated
hydrocarbons, organophosphates are not persistent, usually breaking down two weeks
or less after application. They are nerve poisons, which act to inhibit the enzyme
cholinesterase,
causing the insect to lose coordination and go into convulsion. Methyl parathion,
phosdrin and malathion are examples of this group.
Carbamates

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These are contact poisons, which act in a manner similar to the organophosphates.
Carbamates are widely used in public health work and agriculture because of their
rapid knockdown of insects and low toxicity to mammals.
Pesticide Benefits
Disease control
Insects, rodents and ticks serve as vectors in the transmission of a number of disease-
causing pathogens and parasites. Malaria, yellow fever, trypanosomiasis,
onchocerciasis and plague (Black Death) are some of human diseases that are
transmitted by disease vectors
(insects and rodents). All of these diseases can be reduced by careful use of insecticides.
Crop protection
Plant diseases, insects, bird predation, and competition by weeds reduce crop yield
worldwide by at least one-third. Post-harvest losses to rodents, insects, and fungi may
as much as another 20 to 30 percent. Without the use of pesticides, these losses might
be much higher.
Pesticide Problems
While synthetic chemical pesticides have brought us great economic and social
benefits, they are also causing a number of serious problems. Some of the problems are:
•Killing of beneficial species;
•Development of resistance;
•Environmental contamination
•Hazards to human health especially workers who do not use personal protection
equipment during application (See Fig 4.1).
.
Radioactive Materials
There are various kinds of atoms ofeach elemental substance, each with a slightly
different make-up, some radioactive, some not radioactive. When radioactive materials
are released into the environment, they become dispersed and diluted, but they may
also become

60. 60
concentrated in living organisms and during food chain transfers by a variety of
means. Radioactive substances may also simply accumulate in water, soils sediments,
or air if the input exceeds the rate of natural radioactive decay. Radioactive materials
have the same chemical properties as the non-radioactive forms. Thus, radioactive
iodine (I131), for example, can be
incorporated into thyroxin, the thyroid hormone, as easily as non-radioactive iodine
(I127). Strontium 90 is a radioactive substance. It is chemically very similar to calcium,
and thus tends to be accumulated in the bones and other tissues rich in calcium. It can
also damage the
blood-forming center in the bone marrow.
Prevention and Control of Pollution
As in disease, pollution prevention is far better and more desirable than its cure. There
are various measures that can be taken for preventing pollution. The followings are
some of the measures:
a. Recycling and reuse of waste materials;
b. Waste reduction;
c. Control the use of chemicals;
d. Proper disposal of wastes;
e. Treatment of wastes before discharge;
f. Use of “cleaner” energy sources, such as sun energy, wind,
etc.;
g. Reduce emission of air pollutants using different techniques;
h. Formulation of rules and regulations.

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Fig 4.1. A Farmer in Jimma Zone ready to spray a herbicide with out wearing any form
of personal protective equipment
Water pollution is caused due to several reasons. Here are the few major causes of
water pollution
(i) Domestic effluents and sewage,
Man, for his various domestic purposes such as drinking, cooking, bathing,
cleaning, cooling, etc., uses on an average 135 liters of water per day. About 70 to
80 per cent of this is discharged and drained out, which through municipal drains:
These waste poured into, in many cases, a river, tank or lake Causes of Water Pollution.
Sewage, garbage and liquid waste of households, agricultural lands and factories are
discharged into lakes and rivers. These wastes contain harmful chemicals and toxins
which make the water poisonous for aquatic animals and plants. Sewage is dumped
into rivers which cause severe water pollution problems in following ways:
(i) Bacterial and viral contamination. Sewage wastes may contain pathogenic
bacteria and viruses which are a threat to human health. Waterborne diseases
such as typhoid, bacillary dysentery, amoebic dysentery, poliomyelitis, and
hepatitis all represent potential health hazards in sewage-contaminated
waters. Due to such kinds of sewage pollution waters of many ponds, lakes,
rivers, sea beaches in the world have been prohibited for human use, whether
for drinking, bathing, swimming or other sort of water recreation.
(ii) Eutrophication. According to Hutchinson (1969), the eutrophication is a
natural process which literally means “well-nourished or enriched.” however,

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when abnormally high amounts of nutrients from sewage, fertilizer, animal
wastes and detergents, enter streams and lakes, causing excessive growth or
‘bloom’ of microorganisms and aquatic vegetation. These nutrients stimulate
algal growth and lead to plankton blooms. Plankton blooms of green algae do
not always produce undesirable odours or toxic products, but still create
problems of oxygen supply in the water and also produce obnoxious odours
and tastes in waters
Urbanization
As more and more people move into cities
and towns, a number of factors cause
pollution:
• the physical disturbance of land due to
construction of houses, industries,
roads, etc.;
• chemical pollution from industries,
mines, etc.;
• inadequate sewage collection and treatment;
• increase in fertilizers to grow more food. These results in an increase in nutrients
(nitrates and phosphates) in the water which causes enhanced plant growth
(algal blooms). When this plant material dies and decays the bacteria uses the
oxygen in the water. This lowering of oxygen levels results in the death of other
water life that needs oxygen to survive, eg. Fish, etc. This process is called
eutrophication;
• litter, which causes disease and has a negative visual impact
• Dumping

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Dumping of solid wastes and litters in water bodies causes huge problem. Litters
include glass, plastic, aluminum, Styrofoam etc. Different things take different amount
of time to degrade in water. They affect aquatic plants and animals.
Industrial Waste: Industrial waste contains pollutants like asbestos, lead, mercury and
petrochemicals which are extremely harmful to both people and environment.
Industrial waste is discharged into lakes and rivers by using fresh water making the
water contaminated.
Industries produce waste that can affect the:
• pH of water (whether it is acid, neutral
or alkaline);
• colour of water;
• amount of nutrients (increase in
nutrients can cause eutrophication);
• temperature (increase or decrease in
temperature can have an impact on temperature sensitive organisms living in the
water);
• amount minerals and salts (too much can cause health problems);
• murkiness of water (can block fish gills; bottom dwelling plants cannot
photosynthesize as the sun’s rays cannot reach them; increase in disease as
bacteria and viruses use the soil particles as a method of transportation)

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DEFORESTATION
• Clearing land for agriculture and urban growth often leads to water pollution.
When soil is stripped of its protective vegetation it becomes prone to soil erosion.
This leads to an increase in the murkiness of the water which can cause the
following:
• it can block the gills of fish;
• bottom dwelling plants cannot photosynthesize as the sun’s rays cannot reach
them; and
• there is an increase in disease as bacteria and viruses use the soil particles as a
method of transportation.
Oil Pollution: Sea water gets polluted due to oil spilled from ships and tankers while
traveling. The spilled oil does not dissolve in water and forms a thick sludge polluting
the water. The oil can cause the death to many fish and get stuck to the feathers of
seabirds causing them to lose their ability to fly.

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Do you remember the Oil spill in 2010 Over 1,000 animals (birds, turtles, mammals)
pollution.
Acid Rain: Acid rain is pollution of water caused by air pollution. When the acidic
particles caused by air pollution in the atmosphere mix with water vapor, it results in
acid rain.
Global Warming: Due to global warming, there is an increase in water temperature.
This increase in temperature results in death of aquatic plants and animals. This also
results in bleaching of coral reefs in water.
Energy Use
As human populations increase, more energy is required for human activities such as
cooking, lighting, etc. The majority of our energy in some country comes from the
burning of coal at power stations and results in greatly increased emissions of sulphur

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and nitrogen oxides into the atmosphere. These gases are the main cause of acid rain.
Also the release of carbon dioxide, from the burning of coal, increases global warming
Mining
Mining is the extraction of valuable minerals or
other geological materials from the earth Mines
produce waste that:
• can increase the amount of minerals and
salts in the water (too much can cause health
problems);
• can affect the pH of the water (whether it is acid, neutral or alkaline);
• Can increase the murkiness of the water.

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Agrochemical The consumption of food increase with repaid growth of world
population and it the cry of the day to produce more and more food, where
agrochemicals such as fertilizers, pesticides and herbicides are used, contributes to
heavy water pollution. Pesticides and weedicides are used by human beings to control
crop diseases by the pests or to kill the weeds and, hence, to increase the productivity.
The use of these toxic chemicals has created health hazards not only for livestock and
wild life but also for fish, other, aquatic organisms, birds and mammals including man.
Apart from killing the living organisms present on the surface of the soil, they reach
even the deeper layers through tilling and irrigation of the land, killing still more living
forms which might be involved in soil formation or humus formation, (e.g.,
earthworms, centipede, millipede, etc.). With their continuous use the soil
microorganisms lose their ability of nitrogen fixation. Moreover, when these chemicals
find their way into water supplies, they contaminate and disrupt the aquatic ecosystem
as well
Energy source There are nine major areas of energy resources. They fall into two
categories: nonrenewable and renewable.
Nonrenewable energy resources, like coal, nuclear, oil, and natural gas, are available
in limited supplies.
This is usually due to the long time it takes for them to be replenished. Since the dawn
of humanity people
have used renewable sources of energy to survive wood for cooking and heating, wind
and water for milling
grain, and solar for lighting fires. A little more than 150 years ago people created the
technology to extract
energy from the ancient fossilized remains of plants and animals. These super-rich but
limited sources of
energy (coal, oil, and natural gas) quickly replaced wood, wind, solar, and water as the
main sources of fuel.

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Non-renewable energy resources cannot be replaced – once they are used up, they will
not be restored
(or not for millions of years). Non-renewable energy resources include fossil fuels and
nuclear power
Fossil fuels
Fossil fuels (coal, oil and natural gas) were formed from animals and plants that lived
hundreds of millions of
years ago (before the time of the dinosaurs). They were formed during
the Carboniferous period.
The plants that lived millions of years ago converted the Sun's light
energy into chemical energy through the process
of photosynthesis. This 'solar' energy was (and still is) transferred down the food
chain in animals, and when living
organisms die, the chemical energy within them was trapped.
For a fossil fuel to form, there are three important steps necessary:
Accumulation of organic matter (animal or plant remains),

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preservation of organic matter to prevent it from oxidizing (exclusion of air, for
example, by being in the sea or a swamp) and
conversion of organic matter into a fossil fuel such as oil or natural gas.
This would typically occur due to the organic matter being covered by layers
of sediments, which increases pressure
and heat (50–150°C). Fossil fuels are described as non-renewable because it takes
millions of years for this process
to occur. Burning fossil fuels produces carbon dioxide – one of the greenhouse gases.
Burning coal – one of the
fossil fuels – produces not just carbon dioxide but also releases sulfur into the air,
which increases air pollution.
Coal
Coal is a solid form fossil fuel that can be classed into three types: lignite, bituminous
and anthracite.
Lignite coal is found close to the Earth surface, making it easy to mine, but it has high
sulfur content.
Bituminous coal is the most common coal we burn, and it is less polluting than lignite.
Anthracite is the highest quality of coal – it is dark and shiny and found deeper in the
earth. In addition to pollutants
from burning coal, coal mining creates problems for the environment, as the coal must
be dug from the ground.
Large volumes of unwanted dirt and rock are removed, which can lead to water
pollution, unstable ground and,
in many cases, it is not appealing to look at. Working in coal mines can also be very
dangerous
Oil
Oil is a liquid fossil fuel that can be dark brown, yellow or even green. It is easier to
mine once it is found because,

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being a liquid, it will flow through pipes, which makes it easier for transport. However,
it can be difficult to locate – oil forms in reservoirs and, to find these reservoirs,
scientists must study rocks and landforms to find potential drilling sites
Once a hole is drilled and if oil is found, it is then piped to the surface. In this form, it is
called ‘crude oil’. Crude oil is
Transported to a refinery that heats up the oil to different temperatures and sorts out
the different types of fuel
(such as petrol, jet-fuel and diesel) through a process called fractional distillation. Oil is
used not just for
transport but also in many different products such as plastics, tyres
and synthetic material such as polyester
NATURAL GAS
As the name suggests, this is a fossil fuel in the form of a gas (for example, methane and
LPG).
It is often found under the oceans and near oil deposits. Surveying for natural gas
reservoirs is similar to
oil exploration. Once a natural gas field is found, the drilling process is similar to oil
Gas can be piped from the source and stored for later use. Natural gas is used for
cooking and heating
as well as making a number of products such as plastics, fertilisers and medicines
NUCLEAR ENERGY
nuclear energy is has become a hot technology today. More and more countries are
switching to nuclear
energy to fulfill their future energy demands. Around 16% of world’s electricity
production comes through
nuclear energy. nuclear power plant use Uranium as a fuel to extract energy from it.
The energy can be released through either of the two processes: Nuclear Fission or
Nuclear Fusion.

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Nuclear fission is the most common technique to harness nuclear energy. U-235 element
is bombarded with
slow moving neutrons which break the atom and releases energy. The atoms that got
split are then again
hit by neutrons to produce mass amount of energy. Like fossil fuels, nuclear does not
produces any greenhouse
emissions. Nuclear power plants produce some sort of nuclear waste called radioactive
elements.
These elements emit strong radiations and must be buried deep underground so that
they don’t affect human
life. Couple of nuclear disasters has already occurred in past including Chernobyl and
Island Three Miles.
In the recent past, there is the case of the disaster, which happened in Japan back in
2010. These disasters have
again raised several questions on safety of nuclear power plants and people who work
in these plants. Despite this,
several power stations are coming up in different parts of the world. Another downside
of nuclear energy is that
it can be used to make nuclear bomb. Therefore, these remain targets for various
terrorist organizations
Renewable Resources:
Natural resources that can be regenerated through rapid natural cycles are called
renewable natural resources. Renewable natural resources may be inexhaustible, that is,
resources that are not likely to be exhausted by human consumption such as wind,
sunlight and water. Soil, groundwater, forests and living organisms are exhaustible
resources, which are replenished naturally after their consumption. However, if the
renewable resources are used at a rate faster than the rate at which they are renewed,
they may get exhausted. In a natural cycle, a resource is never lost; it is simply passed
from one form to another. For example, water evaporates from the water bodies to the

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atmosphere, forms clouds and falls down as rain. This water either collects as
groundwater or is returned to rivers and oceans.
Different Types of Renewable Energy Sources
There are different types of energies that are considered renewable energies namely
solar energy, wind energy, tidal energy, hydroelectric energy, geothermal energy,
biomass energy,
1) Solar Energy
Solar energy is one of the most popular and also the fastest growing renewable energy
sources. As a free renewable energy source, technology has created a technique for
connecting the energy of the sun through solar panels. Solar panels are classified into
two type’s namely solar thermal, as well as solar PV cells. Solar PV cells absorb the
sun’s energy and change it into electrical energy which is used in different applications
like electric heating, power appliances, in electric cars, etc. Solar thermal panels use
sun’s energy and these panels are used in taps, heating systems, showers, etc. a solar
energy is the best option in a rising renewable energy marketplace.

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2) Biomass Energy
Biomass energy is most widely used renewable energy. It uses organic materials like
animals, plants, and converts them into another form of energy that can be used. For
instance, when the plants absorb the solar energy through photosynthesis process, then
this energy will pass on through the plant’s organism for making biomass energy. The
common type used for generating biomass energy is crops, wood, and compost. If the
Biomass technology is not controlled properly then it can have a harmful effect on the
environment.
3) Wind Energy
Wind energy has been using for several years for power windmills, pushing sails, and
also for generating force for water pumps. When we contrasted to other types of
renewable energies, wind energy is considered steady as well as very reliable.
At first, the wind farm construction was an expensive project but now the recent
developments have begun for fixing the peak prices in wholesale energy markets
globally and reduce the profits and revenues of the fossil fuel production companies

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4) Hydroelectric Energy
The hydroelectric energy uses the flow of water to rotate turbines for generating
electricity. According to the US survey of geological, this renewable energy provides
20% of the energy in the world energy requirement. There are some issues while using
hydroelectric energy. This energy can be generated from the dammed rivers; otherwise
it can have a major effect on the soil as well as wildlife, and also affects on fish
communities that must journey through the river dams.
5) Tidal Energy
Tidal energy is the same as wind energy but these are predictable as well as steady. This
is the main reason that tidal energy sources are called potential sources. Tidal mills
have been used since the ancient days to middle ages similar to windmills.
Usually, tidal energy has faced from relatively high cost as well as incomplete
accessibility of sites through suitably high tidal ranges. But, several current

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technological developments both in technology and design point outs that the entire
tidal power availability may be superior to previous, and the environmental costs may
be getting down to competitive stages.
The “Rance Tidal Power Station” is the world’s largest tidal energy power plant in
France. And in Scotland and Orkney, the first world’s marine energy center, as well as
the European marine energy center, was established in the year 2003 for developing the
tidal energy & wave energy industry in the UK
6) Geothermal Energy
The term Geothermal taken from the Greek word Geo (Earth), and it receives the heat
from the Earth and converts it into energy. For instance, hot water or steam energy
which are generated from the earth can be utilized for generating energy. It is called to
be a renewable supply of energy because the water in the Earth is filled by normal
rainfall & the heat used is generated through the planet
Ground basis heat pumps can be fixed to connect the normal heat from underground
using fluid tubes covered outside the assets. The fluid in the tubes absorbs the heat
from the ground so it can be used to heat your home and water. For assets that are
located close to a river or lake, it is achievable to fix a heat pump for a water source.
These pipes are flooded in the water as well as a heat pump drives a heat absorbs liquid
during the arrangement of piping. This liquid removes normal heat from the nearby
water to be utilized in the seating arrangement

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Noise Pollution
The word noise is derived from the Latin word ‘Nausea’, which means sickness in
which one feels the need to vomit. Noise is the unpleasant and undesirable sound
which leads to discomfort in human beings. The intensity of sound is measured in
decibels (dB). The faintest sound that the human ear can hear is 1 Db. Due to increasing
noise around the civilizations, noise pollution has become a matter of concern. Some of
its major causes are vehicles, aircraft, industrial machines, loudspeakers, crackers, etc.
When used at high volume, some other appliances also contribute to noise pollution,
like television, transistor, radio, etc.
Types of Noise Pollution
Following are the three types of pollution:
• Transport Noise
• Neighbourhood Noise
• Industrial Noise
Transport Noise
It mainly consists of traffic noise which has increased in recent years with the
increase in the number of vehicles. The increase in noise pollution leads to
deafening of older people, headache, hypertension, etc.
Neighbourhood Noise

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The noise from gadgets, household utensils etc. Some of the main sources are
musical instruments, transistors, loudspeakers, etc.
Industrial Noise
It is the high-intensity sound which is caused by heavy industrial machines.
According to many researches, industrial noise pollution damages the hearing
ability to around 20%.
Causes and Sources of Noise Pollution
Following are the causes and sources of noise pollution:
• Industrialisation: Industrialisation has led to an increase in noise pollution as
the use of heavy machinery such as generators, mills, huge exhaust fans are used,
resulting in the production of unwanted noise.
• Vehicles: Increased number of vehicles on the roads are the second reason for
noise pollution.
• Events: Weddings, public gatherings involve loudspeakers to play music
resulting in the production of unwanted noise in the neighbourhood.
• Construction sites: Mining, construction of buildings, etc add to the noise
pollution.
Noise Pollution Examples
Following are the examples of noise pollution:
• Unnecessary usage of horns
• Using loudspeakers either for religious functions or for political purposes
• Unnecessary usage of fireworks
• Industrial noise

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• Construction noise
• Noise from transportation such as railway and aircraft
Effects of Noise Pollution on Human Health
Noise pollution can be hazardous to human health in the following ways:
• Hypertension: It is a direct result of noise pollution which is caused due to
elevated blood levels for a longer duration.
• Hearing loss: Constant exposure of human ears to loud noise that are beyond the
range of sound that human ears can withstand damages the eardrums, resulting
in loss of hearing.
• Sleeping disorders: Lack of sleep might result in fatigue and low energy level
throughout the day affecting everyday activities. Noise pollution hampers the
sleep cycles leading to irritation and an uncomfortable state of mind.
• Cardiovascular issues: Heart-related problems such as blood pressure level,
stress and cardiovascular diseases might come up in a normal person and a
person suffering from any of these diseases might feel a sudden shoot up in the
level.
Prevention of Noise Pollution
Some noise pollution preventive measures are provided in the points below.
• Honking in public places like teaching institutes, hospitals, etc. should be
banned.
• In commercial, hospital, and industrial buildings, adequate soundproof systems
should be installed.
• Musical instruments’ sound should be controlled to desirable limits.
• Dense tree cover is useful in noise pollution prevention.

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• Explosives should not be used in forest, mountainous and mining areas
Unite
Population
Population The number of individuals of specie living in the same area at the same time
is called population. Population has two aspects: number of individuals of a specie and
area occupied by them. Clarke (1954) formed two types of populations:
Mono-specific: Population of only one specie living in the same area is called Mono-
specific.
Mixed or Poly-specific: Populations of different species living in the same area are
called Poly-specific.
Population has following characteristics:
1. Density: The number of individuals living in a unit area is called density.. For
example number of wheat plants in an acre etc. The unit of density varies in
different species. Density has two types:
▪ Crude density: It is the number of individuals or biomass per unit of total area
inhabited by the specie.
▪ Ecological density: It is the ‘number of individuals or the biomass per unit of that
area actually inhabited by the individual of the specie.
2. Natality or birth rate: The rate at which the new individuals are added to a
population in a unit time is called Natality.
3. Mortality or death rate: The rate at which the individuals are lost by death in a unit
time is called mortality. If the birth rate is more than the death rate, then population
is increasing. If the birth rate is less than death rate, the population is decreasing.
4. Age distribution: The population, of individuals of different ages in the group is
called age distribution. The age groups are pre reproductive, reproductive and
post reproductive.

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5. Dispersion or distribution: It is the random pattern of distribution of individual
of a population over space. It may be of three types:
▪ Random: In this case. the individuals are distributed randomly. For example,
tree of shisham grow randomly in the field.
▪ Uniform: These individuals are evenly spaced. Uniform distribution occurs
when severe competition is present among the plants in a forest.
▪ Clumped: In this case. the individuals occur in scattered groups. Daily and
seasonal w !tether and reproductive pattern causes clumping of trees.
6. Population growth: The number of individuals of population or biomass
increased in unit time is call population growth. There are different patterns of
population growth in plants. Some plants have rapid growth rate. They
increase rapidly and reached the carrying capacity of the field. Then their death
starts due to competition and shortage of nutrients. Some populations have
uniform growth rate. Their death rate is equal to birth rates. Therefore, the
population remains uniform.
7. Competition: The individuals compete with each other for space and
nutrients. Intraspecific competition occurs within same population.
Individuals of the same specie compete with each other. It is more severe
competition because all the individuals have same ecological niche.
Population growth – Types and Regulations
POPULATION GROWTH
The animal population shows birth, death, and dispersal. Therefore, Animal
populations change over time. The death. of individuals is characterized
by survivorship curves. The numbers of survivors are plotted on the Y-axis of a
survivorship graph. Age is plotted on the X-axis. There are three kinds of survivorship
curves:
1. Survivorship curve types I: It gives convex curve. Individuals-in type I
populations survive to an old age. Then they die rapidly. Environmental factors are
not important. They do not influence mortality.Thus most

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individuals live their potential lifespan. Some human populations approach type I
survivorship.
2. Survivorship curve. types II: It gives diagonal line. Individuals in type II
populations have a constant chance of death throughout their lives. The
environment has an important influence on death. It has harsh effect on the young
than on the old. Populations of birds and rodents have type II survivorship curves.
3. Survivorship curve types Ill: It gives concave curve. Individuals in type III
population show very high juvenile mortality. There is much lower mortality rate
in adulthood. Fishes and many invertebrates show type Ill survivorship curves
Types of population growth
There are two type of growth: Exponential growth and Logistic growth.
1. Exponential population growth
Th increase of population by the same ratio per unit time is called exponential
growth. Different populations have different potential to increase the numbers. Not all
populations display the same capacity for growth. Many factors influence the
reproductive potential. These factors are:
▪ umber of offspring produced
▪ he likelihood of survival to reproductive age
▪ he duration of the reproductive period
▪ he length of time it takes to reach maturity,
2. Logistic population growth
The growth in which population reaches a carrying capacity and does inc :ase further
is called logistic population growth. The population size that a particular
environment can support is the environment is called caring capacity. It is symbolized
by K. Exponential growth cannot occur indefinitely. There are many .environmental
resistances. These resistances are climate, food, space. and other environmental. These
resistances check the population growth rate. The population reaches the carrying

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capacity. The growth curves become a sigmoid or flattened S shaped. It is a logistic
population growth.
POPULATION REGULATION •
Every species have different conditions for survival But population density and
competition affect are common in all the species.
Population Density
The number of individuals per unit space is called population density. There are two–
types of factors:
1. Density independent factors: The factors which are not influenced by density of
population are called density independent factors. They influence the number of
animals in a population. The example of these factors is weather conditions. A cold
winter with little snow cover can destroy a population of lizards. These lizards live
beneath the litter of the forest floor. A certain percentage of individuals will freeze to
death. Their death is not affected by the size of the population. Similarly, human
activities like construction and deforestation affect animal populations.
2.. Density-dependent factors: The factors which are influenced by density of
population are called density dependent factors. These factors are more . severe when
population density is large. Animals often use territorial behavior song and scent to
attract partners for reproduction. These actions become more prominent with the
increase of population density. Thus they are density dependent factors. Some other
density-dependent factors are competition for . resources, disease, predation. and
parasitism.
INTERSPECIFIC COMPETITION •
Competition among members of the same species is called interspecific
competition. The animals utilize similar resources. Therefore, they interfere with
each others resources. The resource requirements of individuals of a species
are nearly identical. Therefore, interspecific competition is often intense. There are o
types of interspecific competition:

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▪ can occur without coming into direct contact For example a bird gets the worm. But
it does not actually see later bird.
▪ I can occur in which one individual directly affect another. Its examples
are territorial behavior and the actions of socially dominant individuals.
Community
All populations within an ecosystem are known as a community. The populations in a
community are interconnected to one another. The individuals of these populations
interact among themselves and with individuals of other species to form a community.
“Population interaction is the interaction between different populations. It refers to the
effects that the organisms in a community have on one another.”
The interactions are predation, competition, parasitism, commensalisms, mutualism
and grazing.
Following are the main modes of interaction between populations.
Competition
As the name suggests, it is a relationship when two or more species compete for the
same limited resources at the same time, which may be food, water, light, or any prey.
All these things are crucial for any organism’s growth and survival.
Predation
This is a relationship where one species depends entirely on the other for its food and
survival. The species which feeds on other species is called a predator whereas the one
that is fed upon is called the prey. This entire relationship is called Predation.
Predator is usually stronger than the prey, and hence it consumes prey during its entire
life cycle. In some food chains and food webs, a predator can also fall prey as all living
organisms develop a kind of defence mechanism after a certain period of time.
The words ‘predator’ and ‘prey’ are not always limited to animals. They are implied in
the relationship between animals and plants as well. For example – rabbit feeding on a
carrot, bear eating berry and grasshopper eating a leaf.

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Camouflage
Camouflage literally means ‘to disguise’. It is the phenomenon where an organism or a
species develops structural adaptation that helps them to blend with their surroundings
known as camouflage. This helps them avoid getting detected by predators.
Symbiosis
It is a Greek term which means “living together.” In various relationships among two or
more species or organisms, both parties depend on each other for food and survival. It
is a relationship where one organism lives on another with mutual stereotypic
behaviour.
There are three types of Symbiosis:
Mutualism – where both species are benefitted.
Commensalism – where one species benefits without harming the other.
Parasitism – where one species benefits by harming the other.
Mutualism
It is the ecological interaction between two or more species where each species is
benefitted from the other. It is the most common type of ecological interaction and
describes that mutual dependence is necessary for social well-being. It is dominant in
most communities worldwide.
Commensalism
This is a type of ecological interaction where one organism is benefitted from the other
organism without harming or benefitting it. For eg., cattle egrets and livestock, birds
following army ants, barnacles and whales, etc. all exhibit commensalism.
Parasitism
Parasitism is a one-sided symbiosis, where one organism lives on or in another
organism. The one that feeds on the other organism is called the parasite whereas the
one that is fed upon is called the host. The parasite survives and multiplies using the
host cell machinery and therefore, harms the host

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Ecotone
An ecotone is an area that acts as a boundary or a transition between two ecosystems. A
common example could be an area of marshland between a river and its riverbank.
Ecotones are of great environmental importance. Because the area is a transition
between two ecosystems or biomes, it is natural that it contains a large variety of species
of fauna and flora as the area is influenced by both the bordering ecosystems.
Examples of ecotones include marshlands (between dry and wet ecosystems),
mangrove forests (between terrestrial and marine ecosystems), grasslands (between
desert and forest), and estuaries (between saltwater and freshwater). Mountain ranges
can also create ecotones due to the changes in the climatic conditions on the slopes.
Characteristics of Ecotones
• It may be wide or narrow.
• It is a zone of tension (as it has conditions intermediate to the bordering
ecosystems).
• It could contain species that are entirely different from those found in the
bordering systems.
• Ecotones can be natural or man-made. For example, the ecotone between an
agricultural field and a forest is a man-made one.
Edge Effect
Edge effects refer to the changes in population or community structures that occur at
the boundary of two habitats. Generally, there is a greater number of species found in
these regions (ecotones) and this is called the edge effect. The species found here are
called edge species.
Importance of Ecotone

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1. They have a greater variety of organisms.
2. They also offer a good nesting place for animals coming in search of a nesting
place or food.
3. They serve as a bridge of gene flow from one population to another because of
the larger genetic diversity present.
4. They can act as buffer zones offering protection to the bordering ecosystems
from possible damage. For example, a wetland can absorb pollutants and
prevent them from seeping into the river.
5. Ecotones are also a sensitive indicator of global climate change. A shifting of
boundaries between ecosystems is thought to be due to climate change. So,
scientists and environmentalists are studying ecotones with greater interest now.
Ozone Layer and its Depletion
Ozone Layer Definition
“The ozone layer is a region in the earth’s stratosphere that contains high concentrations
of ozone and protects the earth from the harmful ultraviolet radiations of the sun.”
Ozone Layer Depletion?
Ozone layer depletion is the thinning of the ozone layer present in the upper
atmosphere. This happens when the chlorine and bromine atoms in the atmosphere
come in contact with ozone and destroy the ozone molecules. One chlorine can destroy
100,000 molecules of ozone. It is destroyed more quickly than it is created.
Some compounds release chlorine and bromine on exposure to high ultraviolet light,
which then contributes to ozone layer depletion. Such compounds are known as Ozone
Depleting Substances (ODS).
The ozone-depleting substances that contain chlorine include chlorofluorocarbon,
carbon tetrachloride, hydrochlorofluorocarbons, and methyl chloroform. Whereas, the
ozone-depleting substances that contain bromine are halons, methyl bromide, and
hydro bromofluorocarbons.
Chlorofluorocarbons are the most abundant ozone-depleting substance. It is only when
the chlorine atom reacts with some other molecule, it does not react with ozone.

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Montreal Protocol was proposed in 1987 to stop the use, production and import of
ozone-depleting substances and minimise their concentration in the atmosphere to
protect the ozone layer of the earth.
Causes of Ozone Layer Depletion
Ozone layer depletion is a major concern and is associated with a number of factors.
The main causes responsible for the depletion of the ozone layer are listed below:
Chlorofluorocarbons
Chlorofluorocarbons or CFCs are the main cause of ozone layer depletion. These are
released by solvents, spray aerosols, refrigerators, air-conditioners, etc.
The molecules of chlorofluorocarbons in the stratosphere are broken down by
ultraviolet radiations and release chlorine atoms. These atoms react with ozone and
destroy it.
Unregulated Rocket Launches
Researchers say that the unregulated launching of rockets results in much more
depletion of the ozone layer than the CFCs do. If not controlled, this might result in a
huge loss of the ozone layer by the year 2050.
Nitrogenous Compounds
The nitrogenous compounds such as NO2, NO, N2O are highly responsible for the
depletion of the ozone layer.
Natural Causes
The ozone layer has been found to be depleted by certain natural processes such as Sun-
spots and stratospheric winds. But it does not cause more than 1-2% of the ozone layer
depletion.
The volcanic eruptions are also responsible for the depletion of the ozone layer.
Effects Of Ozone Layer Depletion
The depletion of the ozone layer has harmful effects on the environment. Let us see the
major effects of ozone layer depletion on man and environment.
Effects on Human Health
Humans will be directly exposed to the harmful ultraviolet radiation of the sun due to
the depletion of the ozone layer. This might result in serious health issues among
humans, such as skin diseases, cancer, sunburns, cataract, quick ageing and weak
immune system.
Effects on Animals

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Direct exposure to ultraviolet radiations leads to skin and eye cancer in animals.
Effects on the Environment
Strong ultraviolet rays may lead to minimal growth, flowering and photosynthesis in
plants. The forests also have to bear the harmful effects of the ultraviolet rays.
Effects on Marine Life
Planktons are greatly affected by the exposure to harmful ultraviolet rays. These are
higher in the aquatic food chain. If the planktons are destroyed, the organisms present
in the food chain are also affected.
Solutions to Ozone Layer Depletion
The depletion of the ozone layer is a serious issue and various programmes have been
launched by the government of various countries to prevent it. However, steps should
be taken at the individual level as well to prevent the depletion of the ozone layer.
Following are some points that would help in preventing this problem at a global level:
Avoid Using ODS
Reduce the use of ozone depleting substances. E.g. avoid the use of CFCs in
refrigerators and air conditioners, replacing the halogen based fire extinguishers, etc.
Minimise the Use of Vehicles
The vehicles emit a large amount of greenhouse gases that lead to global warming as
well as ozone depletion. Therefore, the use of vehicles should be minimised as much as
possible.
Use Eco-friendly Cleaning Products
Most of the cleaning products have chlorine and bromine releasing chemicals that find a
way into the atmosphere and affect the ozone layer. These should be substituted with
natural products to protect the environment.
Use of Nitrous Oxide should be Prohibited
The government should take actions and prohibit the use of harmful nitrous oxide that
is adversely affecting the ozone layer. People should be made aware of the harmful
effects of nitrous oxide and the products emitting the gas so that its use is minimised at
the individual level as well.
What is Acid Rain?
Acid Rain, as the name suggests, can be said as the precipitation of acid in the form of
rain in the simplest manner. When atmospheric pollutants like oxides of nitrogen and

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sulphur react with rainwater and come down with the rain, then this results in Acid
Rain
Acid Rain Definition
Acid rain is made up of highly acidic water droplets due to air emissions, most
specifically the disproportionate levels of sulphur and nitrogen emitted by vehicles and
manufacturing processes. It is often called acid rain as this concept contains many types
of acidic precipitation.
The acidic deposition takes place in two ways: wet and dry. Wet deposition is any form
of precipitation which removes acids from the atmosphere and places them on the
surface of the earth. In the absence of precipitation, dry deposition of polluting particles
and gases sticks to the ground through dust and smoke.
Causes of Acid Rain
The causes of acid rain are Sulphur and Nitrogen particles which get mixed with the
wet components of rain. Sulphur and Nitrogen particles which get mixed with water
are found in two ways either
man-made i.e as the emissions that are given out from industries or
Naural causes like lightning strike in the atmosphere releasing nitrogen oxides and
volcanic eruptions releasing sulphur oxide.
According to the Royal Society of Chemistry, which considers him the “father of acid
rain,” the word acid rain was invented in 1852 by Scottish chemist Robert Angus Smith.
Smith decided on the word while studying rainwater chemistry near industrial towns in
England and Scotland.
The regular clean rain we experience, even though it is not clean i.e water and carbon
dioxide react together to form weak carbonic acid which essentially by itself is not
extremely harmful. The reaction occurring is :
H2O (l) + CO2 (g) ⇌ H2CO3 (aq)
The pH value of regular rainwater is around 5.7, giving it an acidic nature. The oxides
of nitrogen and sulphur are blown away by the wind along with the dust particles.
They settle on the earth’s surface after coming down in the form of precipitation. Acid
rain is essentially a by-product of human activities which emit oxides of nitrogen and
sulphur in the atmosphere. Example – the burning of fossil fuels, unethical waste
emission disposal techniques.

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2SO2 (g) + O2 (g) + 2H2O (l) → 2H2SO4 (aq)
4NO2 (g) + O2 (g) + 2H2O (l) → 4HNO3 (aq)
Sulphur dioxide and nitrogen dioxide undergo oxidation, and then they react with
water resulting in the formation of sulphuric acid and nitric acid, respectively. The
following reaction will clarify the acid formation reaction:
Effects of Acid Rain
• Acid rain is very harmful to agriculture, plants, and animals. It washes away all
nutrients which are required for the growth and survival of plants. Acid rain
affects agriculture by the way it alters the composition of the soil.
• It causes respiratory issues in animals and humans.
• When acid rain falls down and flows into the rivers and ponds it affects the
aquatic ecosystem. It alters the chemical composition of the water, to a form
which is actually harmful to the aquatic ecosystem to survive and causes water
pollution.
• Acid rain also causes the corrosion of water pipes, which further results in
leaching of heavy metals such as iron, lead and copper into drinking water.
• It damages the buildings and monuments made up of stones and metals.

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Real-Life Examples
• Taj Mahal, one of the 7 wonders of the world, is largely affected by acid rain.
The city of Agra has many industries which emit the oxides of sulphur and
nitrogen in the atmosphere. People continue to use low-quality coal and
firewood as a domestic fuel, adding to this problem. Acid rain has the following
reaction with the marble (calcium carbonate):
CaCO3(s) + H2SO4(l) → CaSO4(s) + H2O(l) + CO2(g)
The formation of calcium sulphate results in the corrosion of this beautiful monument.
• Statue of Liberty which is made of copper has also been damaged by the
cumulative action of acid rain and oxidation for over 30 years and is, therefore,
becoming green.

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Prevention of Acid Rain
• The only precaution that we can take against acid rain is having a check at the
emission of oxides of nitrogen and sulphur.
• Acid rain is harmful to animals, plants and the monuments.
• Being responsible citizens, one should be aware of the harmful effects they cause
and of the industries which give out nitrogen and sulphur compound wastes
unethically.
Greenhouse Effect Definition
“Greenhouse effect is the process by which radiations from the sun are absorbed by the
greenhouse gases and not reflected back into space. This insulates the surface of the
earth and prevents it from freezing.”
Greenhouse Gases
“Greenhouse gases are the gases that absorb the infrared radiations and create a
greenhouse effect. For eg., carbondioxide and chlorofluorocarbons.”
Greenhouse Effect Diagram

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The major contributors to the greenhouse gases are factories,
automobiles, deforestation, etc. The increased number of factories and automobiles
increases the amount of these gases in the atmosphere. The greenhouse gases never let
the radiations escape from the earth and increase the surface temperature of the earth.
This then leads to global warming.
Causes of Greenhouse Effect
The major causes of the greenhouse effect are:
Burning of Fossil Fuels
Fossil fuels are an important part of our lives. They are widely used in transportation
and to produce electricity. Burning of fossil fuels releases carbon dioxide. With the
increase in population, the utilization of fossil fuels has increased. This has led to an
increase in the release of greenhouse gases in the atmosphere.
Deforestation
Plants and trees take in carbon dioxide and release oxygen. Due to the cutting of trees,
there is a considerable increase in the greenhouse gases which increases the earth’s
temperature.
Farming
Nitrous oxide used in fertilizers is one of the contributors to the greenhouse effect in the
atmosphere.
Industrial Waste and Landfills
The industries and factories produce harmful gases which are released in the
atmosphere.
Landfills also release carbon dioxide and methane that adds to the greenhouse gases.
Effects of Greenhouse Effect
The main effects of increased greenhouse gases are:
Global Warming
It is the phenomenon of a gradual increase in the average temperature of the Earth’s
atmosphere. The main cause for this environmental issue is the increased volumes of
greenhouse gases such as carbon dioxide and methane released by the burning of fossil
fuels, emissions from the vehicles, industries and other human activities.

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Depletion of Ozone Layer
Ozone Layer protects the earth from harmful ultraviolet rays from the sun. It is found in
the upper regions of the stratosphere. The depletion of the ozone layer results in the
entry of the harmful UV rays to the earth’s surface that might lead to skin cancer and
can also change the climate drastically.
The major cause of this phenomenon is the accumulation of natural greenhouse gases
including chlorofluorocarbons, carbon dioxide, methane, etc.
Smog and Air Pollution
Smog is formed by the combination of smoke and fog. It can be caused both by natural
means and man-made activities.
In general, smog is generally formed by the accumulation of more greenhouse gases
including nitrogen and sulfur oxides. The major contributors to the formation of smog
are automobile and industrial emissions, agricultural fires, natural forest fires and the
reaction of these chemicals among themselves.
Acidification of Water Bodies
Increase in the total amount of greenhouse gases in the air has turned most of the
world’s water bodies acidic. The greenhouse gases mix with the rainwater and fall as
acid rain. This leads to the acidification of water bodies.
Also, the rainwater carries the contaminants along with it and falls into the river,
streams and lakes thereby causing their acidification.
Runaway Greenhouse Effect
This phenomenon occurs when the planet absorbs more radiation than it can radiate
back. Thus, the heat lost from the earth’s surface is less and the temperature of the
planet keeps rising. Scientists believe that this phenomenon took place on the surface of
Venus billions of years ago.
This phenomenon is believed to have occurred in the following manner:
• A runaway greenhouse effect arises when the temperature of a planet rises to a
level of the boiling point of water. As a result, all the water from the oceans
converts into water vapour, which traps more heat coming from the sun and
further increases the planet’s temperature. This eventually accelerates the
greenhouse effect. This is also called the “positive feedback loop”.
• There is another scenario giving way to the runaway greenhouse effect. Suppose
the temperature rise due to the above causes reaches such a high level that the
chemical reactions begin to occur. These chemical reactions drive carbon dioxide
from the rocks into the atmosphere. This would heat the surface of the planet

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which would further accelerate the transfer of carbon dioxide from the rocks to
the atmosphere, giving rise to the runaway greenhouse effect.
In simple words, increasing the greenhouse effect gives rise to a runaway greenhouse
effect which would increase the temperature of the earth to such an extent that no life
will exist in the near future.
What is Kyoto Protocol?
The Kyoto Protocol is an international agreement that brings into operation the United
Nations Framework Convention on Climate Change (UNFCCC). It is the first set of
international rules designed to implement the UNFCCC. UNFCCC is a multilateral
environmental treaty that came into force on 21 March1994, at the Earth Summit, New
York City in the year1992,to combat climate change. Its role is to fight global warming
by reducing greenhouse gas concentrations in the atmosphere to a level that
Would prevent dangerous anthropogenic interference with the climate systems.
The Kyoto Protocol is based on the principles and provisions of the Convention and
follows its annex-based structure. It only binds developed countries, and places a
heavier burden on them under the principle of ‘common but differentiated
responsibility and respective capabilities’, because it recognizes that they are largely
responsible for the current high levels of GHG emissions in the atmosphere. The Kyoto
Protocol implemented the objective of the UNFCCC ( UNFCCC stands for United
Nations Framework Convention on Climate Change) to fight global warming by
reducing greenhouse gas concentrations. As of today, there are 192parties to the Kyoto
Protocol.
Origin and History of Kyoto Protocol
In 1997, the third meeting of the UNFCCC nation (United Nations Framework
Convention on Climate Change) took place, in Japan, where the Kyoto Protocol was
created. The Kyoto Protocol was adopted on 11 December1997.It entered into force on
16 February2005 following ratification by Russia. Kyoto is the name of the Japanese city
in which the protocol was negotiated, but it is now commonly used in climate change
discussions to refer to the protocol itself.
Principles of the Kyoto Protocol

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The Kyoto Protocol is based on the principle of‘ Common But Differentiated
Responsibilities (CBDR)‘.It puts the obligation to reduce current emissions on
developed countries on the basis that they are historically responsible for the current
levels of greenhouse gases in the atmosphere.
According to the CBDR, the Kyoto Protocol divides the responsibilities of different
countries into two
ways:
Historical Polluters (Developed countries)
Historically, the biggest polluting developed countries are polluting the earth since the
Industrial Revolution. These countries include- the US, UK, France, Japan, Russia, etc.
Under the CBDR,( common but differentiated responsibilities), developed countries
like the US, UK, Russia, etc. must contribute more towards the implementation of ways
to reduce GHGs. They must do so by:
● Accepting the certain binding limits on GHG emissions.
● Contributing funds towards reducing GHG emissions in the developing and the least
developed countries.
2. Recent Polluters (Developing countries)
Recently polluting developing countries are countries that have been polluting since the
1950s. These include countries like China, India, Brazil, etc. Such countries should do
everything possible to cut down their GHG emissions. But these countries are not
bound, and every initiative taken by these countries is voluntary.
Responsibilities and Targets of the Kyoto Protocol
The Kyoto Protocol is designed to assist countries in adapting to the adverse effects of
climate change. It facilitates the development and implementation of techniques that
can help increase resilience to the impacts of climate change. One of the major features
of the Kyoto Protocol is that it sets obligatory targets for 37 industrialized countries and
the European community for reducing greenhouse gas (GHG) emissions.
The protocol does not set reduction targets for developing countries on the principle
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clean it up. However, rapidly developing economies such as those of China and India
will have a huge impact on GHG emissions in the future. The lack of developing
country commitments is one of the reasons why the United States refused to ratify
Kyoto.
The agreement and its widespread acceptance (184 countries have ratified it) provide
Important international momentum for action on climate change. The targeted gases
under this protocol are as follows:
● Carbon Dioxide (CO2)
● Methane (CH4)
● Nitrous Oxide (N2O)
● Sulphur Hexafluoride (SF6)
● Hydrofluorocarbons (HFCs)
● Perfluorocarbons (PFCs)
Parties under the Kyoto Protocol
The parties under the Kyoto Protocol are divided in the following manner:
Annexe I:
● Developed countries [US, UK, Russia etc.]
● Economies in transition (EIT) [Ukraine, Turkey, some eastern European countries
etc.]
Annexe II:
● Developed countries (Annex II is a subset of Annex I).
● Required to provide financial and technical support to the EITs and developing
countries to assist them in reducing their greenhouse gas emissions.
Annexe B:
● Annexe I Parties with first or second-round Kyoto greenhouse gas emissions
targets.
● The first-round targets apply over the years 2008–2012 and the second-round
Kyoto targets, apply from 2013 to 2020.
● Compulsory binding targets reduce GHG emissions.

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Non-Annex I:
● Parties to the UNFCCC are not listed in Annex I of the Convention (mostly low
income developing countries).
● No binding targets to reduce GHG emissions.
LDCs
● Least-developed countries
● No binding targets to reduce GHG emissions.
The Kyoto Mechanisms
The Kyoto mechanisms improve the possibility of skipping the use of older, dirtier
technology for newer, cleaner infrastructure and systems, with obvious longer-
term benefits that are more economical. Countries bound to Kyoto targets have to
meet them largely through domestic action, i.e., by reducing their emissions
onshore. But they can meet part of their targets through three ‘market-based
mechanisms’, called the Kyoto mechanisms.
The Kyoto Flexible Market Protocol mechanisms include:
Clean Development Mechanism (CDM)
Developed countries emit more and lose carbon credits. They provide financial
assistance to developing and least developed countries to create clean energy
(solar, wind energy, etc.) and gain some carbon credits thereby meeting their
Kyoto Quota (Kyoto units) of emissions without violations.
Emission Trading
Emissions trading allow countries to sell unused emission units to countries that
have exceeded their targets. Carbon is tracked and traded like any other
commodity in a “carbon market.”
Joint Implementation (JI)
This mechanism allows a country with an emission reduction commitment under
the Kyoto Protocol (Annex B Party) to earn emission reduction units (ERUs) from
an emission-reduction project in another Annex B Party, each equivalent to one
tonne of CO2, which can be counted towards meeting its Kyoto target. The joint

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implementation offers Parties a flexible and cost-efficient means of fulfilling a part
of their Kyoto commitments, while the host Party benefits from foreign investment
and technology transfer.
Doha Amendment
In Doha, Qatar, on 8 December 2012, the Doha Amendment to the Kyoto Protocol
was adopted for a second commitment period, starting in 2013 and lasting until
2020. As of 28 October 2020, 147 Parties deposited their instrument of acceptance;
therefore the threshold of 144 instruments of acceptance for entry into force of the
Doha Amendment was achieved. The amendment entered into force on 31
December 2020. During the first commitment period, 37 industrialized countries
and economies were in transition, and the European Community committed to
reduce GHG emissions to an average of five percent against 1990 levels. During
the second commitment period, Parties committed to reducing GHG emissions by
at least 18 percent below 1990 levels in the eight-year period from 2013 to 2020;
however, the composition of Parties in the second commitment period is different
from the first.
Desertification is the degradation process by which a fertile land changes itself into a
desert by losing its flora and fauna, this can be caused by drought, deforestation,
climate change, human activities or improper agriculture. Desertification is a process of
degradation of the land. It occurs because of man-made activities and climate change.
Desertification takes place when a particular type of biome converts into a desert
biome.
Desertification Causes
1. Overgrazing
2. Deforestation
3. Farming Practices
4. Urbanization and other types of land development
5. Climate Change
6. Stripping the land of resources

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Natural Disasters
Desertification Impacts
1. Farming becomes difficult or even impossible in the area
2. Flooding chances are more
3. Hunger – because of no farming
4. Poor quality of water
5. Overpopulation
6. Poverty as a result of the above
Steps To Reduce Desertification
Given below are the steps which may help in reducing Desertification:
• Focus on Water management. Rainwater harvest must be done, water that can be
reused must not be left out as waste
• Reforestation and tree regeneration
• Buttressing the soil through the use of sand fences, shelter belts, woodlots and
windbreaks
• Better and hyper-fertilization of soil through planting
• The residue from pruned trees can be used to provide mulching for fields thus
increasing soil water retention and reducing evaporation
Deforestation. Human-caused or natural causes which lead to the cutting down of
trees and reduced forest areas is called deforestation. Generally, it is the human
activities of urbanisation, construction etc., which have been the major cause of
deforestation across the world.
Causes of deforestation
Given below are the major causes of deforestation:
• Commercial or Industrial Agriculture
• Construction of new buildings, roads, and other infrastructural facilities
• Increased Population

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• Mining is another important factor for the increased cutting down of trees and
forest areas
• The change in climate is one of the main natural causes which has resulted in loss
of forests
• Natural calamities
• Unsustainable forest management
Effects of Deforestation
Deforestation has impacted the environment and livelihood of many. Discussed below
are a few of the main effects of deforestation:
• Loss of habitat for various animal and plant species
• Environmental Disbalance is another side effect of deforestation. Due to the
absence of an ample number of trees and forest areas across the globe, the
environment and the atmosphere is facing severe climatic changes
• A lot of people rely on forests for their livelihood. These people are adversely
affected due to deforestation
• It degrades the quality of soil
• The water cycle gets disturbed
Measurement to control deforestation
There are certain measures which can be adapted by people in their day to day
lives to reduce this loss of trees and forests. Given below are the same:
• Plant a tree whenever and wherever possible
• Rely on the concept of reducing, reusing and recycling
• Try reducing the use of paper since it is obtained through a tree
• Spread awareness about the importance of afforestation
• Promote products which ensure reduced or no deforestation
NAME RAZA MUHAMMAD
ADRESS, OLANDAR, P/O BILKANI, T/H ALPURI DISTT SHANGLA
Whatsapp 0346 7830036