evs UNIT-2nd ecosystem.pptx

Subject: Environmental Sciences
(Theory)
Subject Code: BP206T
(B.Pharm 2nd Sem.)
Surya Prabhakar Singh
(Assistant Professor)
PSIT (Pharmacy)
Kanpur, UP
PSIT (Pharmacy)
Surya Prabhahakar singh ( PSIT ; Kanpur)

Unit – 2nd MODULE 3rd & 4th
Ecosystem
Module – 3rd
Topic cover-
 introduction ,
 Concepts of an ecosystem
 Structure and function of an
ecosystem
 Ecological pyramid
 Energy chain and web

ECOSYSTEM
• Definition-
The term ‘ecosystem’ was coined by A.G.
Tansley in 1935.
 An ecosystem is a functional unit of nature
encompassing complex interaction between its
biotic (living) and abiotic (non-living)
components.
For example- a pond is a good example of
ecosystem.

Concept of an Ecosystem:
The term ‘ecosystem’ was coined by A.G. Tansley, an English
botanist, in 1935. An ecosystem is the structural and
functional unit of ecology (nature) encompassing complex
interaction between its biotic (living) and abiotic (non-
living) components.
For example- a pond is a good example of ecosystem. A
pond, lake, desert, grassland, meadow, forest etc. are
common examples of ecosystems.
According to George Usher “The complete ecological system
of an area including plants, animals and the environmental
factors is known as ecosystem”

Structure and Function of an
Ecosystem
Each
ecosystem has
two main
components:
(1)
Abiotic
(2) Biotic

(a) Abiotic components (Nonliving): The abiotic component
can be grouped into
following three categories:-
(i) Physical factors: Sun light, temperature, rainfall,
humidity and pressure.
They sustain and limit the growth of organisms in an
ecosystem.
(ii) Inorganic substances: Carbon dioxide, nitrogen, oxygen,
phosphorus, sulphur, water, rock, soil and other minerals.
(iii) Organic compounds: Carbohydrates, proteins, lipids
and humic substances.
They are the building blocks of living systems and
therefore, make a link between the biotic and abiotic
components.

Biotic
• Biological components refer to all living organisms in the
ecosystem.
• These components typically include organisms such as
animals, plants, humans, and other microorganisms. Based on
different nutrition, biological components are classified into
the following three categories:
PCD
• Producers: Producers, also called autotrophs, produce foods
for many other organisms using photosynthesis. Plants and
trees fall under the category of producers.
• All other biotic components (organisms measured above
producers in a food chain) rely on producers for food directly
or indirectly. Surya Prabhahakar singh ( PSIT ; Kanpur)

Consumers: Consumers, also known as heterotrophs,
include organisms that depend on other organisms for their
food needs. Consumers are divided into primary, secondary,
tertiary, and quaternary consumers.
Decomposers: Decomposers are also known as detritus or
saprophytes.
These include microbes such as fungi and bacteria.
Decomposers mainly rely on dead and rotting organic
components for their food requirements. They are essential
components of the ecosystem because they participate in
recycling nutrients, making them reusable for plants and
trees.

FUNCTIONAL ASPECTS OF AN ECOSYSTEM

ecological Pyramid
• An ecological pyramid is a
graphical representation of the
relationship between the
different living organisms at
different trophic levels. It was
given by G.Evylen Hutchinson
and Raymond Lindeman.
• It can be observed that these
pyramids are in the shape of
actual pyramids with the base
being the broadest, which is
covered by the lowest trophic
level, i.e., producers. The next
level is occupied by the next
trophic level, i.e., the primary
consumers and so on.

Types of Ecological Pyramid
3 types
Pyramid of numbers
Pyramid of biomass
Pyramid of energy

Pyramid of numbers
• The total number of individuals (population) present at
each trophic level is represented by a pyramid of numbers.
• Elton John popularised the term "pyramid of numbers" in
1972.
• When it comes to counting the number of creatures, this
pyramid is really efficient.
• Counting is a basic task that can be done over time to
determine how an ecosystem has changed. However, some
creatures, particularly young forms, are difficult to count.
• Except in rare cases, such as the detritus food chain, where
many creatures feed on a single dead plant or animal, the
number pyramid is normally vertical

Forest ecosystem no. pyramid
(spindle shaped)

Parasitic food chain
(inverted shaped)

Pond ecosystem (Upright)

Grass land (upright)

Pyramid of energy
In an ecosystem the pyramid of energy shows the
amount of total energy trapped by the organism at
each trophic level in a unit area and time and
expressed as kcal/m2/year.
Energy pyramids provide the best picture of overall
nature of the ecosystem.
Energy pyramid is always upright in all ecosystems

Pyramid of biomass
The amount of living
material in an
organism is called
biomass.
Pyramid of biomass
shows quantitative
relationship existing at
various trophic levels.

The food web

Cont…

The food chain
• The sequence of living organisms in a
community in which one organism consumes
another organism to transfer food energy is
called a food chain.
• An example of a simple food chain is that
operating in a grassland:
Grass(Producer)⟶Deer(Herbivore)⟶Lion(Carnivore)

Types of Food Chain
• There are two types of food chains, detritus food
chain and the grazing food chain.
• Detritus food chain: The detritus food chain includes
different species of organisms and plants like algae,
bacteria, fungi, protozoa, mites, insects, worms and
so on. The detritus food chain begins with dead
organic material.
• The food energy passes into decomposers and
detritivores, which are further eaten by smaller
organisms like carnivores.
• Carnivores, like maggots, become a meal for bigger
carnivores like frogs, snakes and so on.
• Primary consumers like fungi, bacteria, protozoans,
and so on are detritivores which feed on detritus

Grazing food chain
The grazing food
chain is a type of food
chain that starts with
green plants, passes
through herbivores
and then to
carnivores.
In a grazing food
chain, energy in the
lowest trophic level is
acquired from
photosynthesis.

Module – 4th
Types of ecosystem
Topic cover- introduction , type characteristic features , structure and function of
the different ecosystem –
 Forest ecosystem
 Grassland
 Desert
 Aquatic

General structure of ecosystems

Types of Ecosystem
• There are two types of ecosystems, mainly:
• 1. Terrestrial Ecosystems: Terrestrial ecosystems
are classified into various types based on temperature
and annual rainfall. A few examples of terrestrial
ecosystems are listed below:
a. Grassland Ecosystems
b. Forest Ecosystems
c. Desert Ecosystems
• 2. Aquatic Ecosystems: Aquatic ecosystems are
majorly two types-
a. Freshwater/Inland Ecosystems
b. Marine/Saltwater Ecosystems

Forest ecosystem
• What is a Forest Ecosystem?
• A forest ecosystem is an ecosystem of forests
and resources. Forests are renewable natural
resources.
• Forests are formed by a community of plants
that are predominantly structurally defined by
their trees, shrubs, herbs, climbers and ground
cover. Soil, animals, insects, microorganisms
and birds are the most important interacting
units of a forest ecosystem. In India, the forests
occupy about 18−20% of the total land area

Components of forest ecosystem
Abiotic-
• of the forest include inorganic and organic
components present in the soil along with
temperature, rainfall, light, etc.
Biotic –
• are represented by producers, consumers
and decomposers

Cont…
Nutrient Cycle:
The nutrient cycle is cyclic. For the proper functioning of ecosystems, nutrients
are required. Carbon, hydrogen, oxygen, and nitrogen constitute about 95% of
the mass of living organisms. About 15 to 20 other elements are also needed in
relatively small amounts. These are recycled repeatedly between the living and
non-living components of the ecosystem.
Energy Flow:
In a forest ecosystem, the grass, which draws its nutrition from sun, soil and water, is eaten by the
grasshopper, which in turn is eaten by frogs, snakes and vultures in succession (different trophic
levels). In this process of eating and being eaten, nutrients are passed from one step to the next in
a food chain. The flow of energy that occurs along a food chain is called energy flow. The pyramid
of energy represents the total quantity of energy at each trophic level of a food chain. The flow of
energy is always unidirectional.

What are the Types of Forest
Ecosystems?
• There are a few types of forest ecosystems listed below:
• 1. Tropical Evergreen Rainforest: Only a small percentage of tropical forests are
rainforests where average rainfall is 80−400 inches in a year. This forest is
characterised by deep and dense vegetation consisting of tall trees reaching
different levels.
• 2. Tropical Deciduous Rainforest: The main characteristic of tropical deciduous
rainforest are broad-leaved trees along with dense bushes, shrubs, etc. Two
main seasons- summer and winter are distinctly visible there. This type of forest
is found in many parts of the world. A large variety of flora and fauna are found
here.
• Temperate Evergreen Forest: Temperate evergreen forest is a type of forest that
is characterised by a smaller number of trees but an adequate number of ferns
and mosses.
• Temperate Deciduous Forest: Temperate deciduous forest evolves in the moist
temperate region with sufficient rainfall. Here also, winter and summer are well
defined, and trees shed their leaves during winter.

Threats To The Forest Ecosystem
• Forest fire
• Overgrazing
• Mountain and forest roads
• Timber extraction for various
purpose
• Hydroelectric projects
• Jhuming / shiftting
cultivation
• Mining and canals
Main threat to
the forest is
form human
activities as
fallow:-

What if the forest disappear ?
Change in
climate due to
reduce rainfall,
increased
sunlight, hotter
summers, and
colder winters.
Global
warming
increasing
Decrease in
amount and
periodicity of
rain fall.
Co2 incerase
Any many
more…..?

How can be forest ecosystem?

• Conservation of forest is the practice of planting
more trees and maintaining the forested areas for
the sustainability for future generations. Forests
are an important natural resource and are
beneficial to humans in several ways. But due to
increasing deforestation activities, it has become
essential to conserve forests throughout the world.
Deforestation is the permanent destruction or loss
of forests for the expansion of lands for agriculture,
livestock, etc.
• The process of destructing forests for the
expansion of agricultural land is referred to as
shifting cultivation.
How can be forest ecosystem?

Following are some of the major steps for conservation of forest:
• With the advent of industrialization, several trees have been cut at an alarming
rate for raw materials and various other purposes. This felling of trees can be
regulated by selective cutting, clear-cutting Forest fires are one of the common
causes of loss of forests. Sometimes the forest land is set on fire to make the
land available for commercial purposes. Once cleared, there can be no
vegetation.
• Natural forest fires are also responsible for the destruction of huge forest
covers. Latest fire fighting techniques should be adopted to conserve the
forest. However, forest fires are an important part of the ecosystem and it
helps replenish nutrients in the soil from dead and decaying matter.
• More trees should be planted to increase the forest cover. Trees should be
selected according to the geographical conditions of a particular region and
proper care should be taken during the growth of trees.
• Prevention of exploitation of forestry and forest products is necessary for the
conservation of forest.
• The existing forests should be protected from diseases by spraying chemicals,
antibiotics or development of pest-resistant strains of trees

Grassland ecosystem
What is grassland ecosystem?
• Grasslands are one of the intermediate stages in ecological
succession and cover a part of the land on all the altitudes and
latitudes at which climatic and soil conditions do not allow the
growth of trees.
• Grasslands make up almost a quarter of the total land surface.
The types of plants that grow here greatly depend on what the
climate and soil are like.
• Grasslands cover areas where rainfall is usually low and/or the
soil depth and quality is poor.
• The low rainfall prevents the growth of numerous trees and
shrubs but is sufficient to support the growth of grass cover
during the monsoon

Structure/Components of Grassland Ecosystem
The different structural
components of the
grassland ecosystem can
be classified as abiotic
and biotic components.
Biotic Components
Producers – In grassland,
producers are mainly
grasses; though, a few herbs
& shrubs also contribute to
the primary production of
biomass.
Decomposers – These include
bacteria of death and decay,
moulds and fungi (e.g., Mucor,
Penicillium,, Rhizopus, etc). These
bring the minerals back to the soil
to be available to the producers
again.

Consumers – In a grassland, consumers are of
three main types:
Primary Consumers – The primary consumers are herbivores
feeding directly on grasses. Herbivores such as grazing mammals
(e.g., cows, sheep, deer, rabbit, buffaloes, etc), insects (e.g.,
Dysdercus, Coccinella, Leptocorisa, etc),
Secondary Consumers – These are carnivores that feed on primary
consumers (Herbivores). The animals like foxes, jackals, snakes, frogs, lizards, birds
etc., are the carnivores feeding on the herbivores. These are the secondary
consumers of the grassland ecosystem.
Tertiary Consumers – These include hawks etc. which feed on secondary
consumers.

Types of grassland
Grasslands in India
 In India, grasslands are found as village grazing grounds
(Gauchar) and extensive low pastures of dry regions of the
western part of the country and also in Alpine Himalayas.
 Perennial grasses are the dominant plant community.
 In the Himalayan mountains, there are high, cold Himalayan
pastures.
 There are tracts of tall elephant grass in the low-lying Terai
belt south of the Himalayan foothills.
 There are semi-arid grasslands in Western India, parts of Central
India, and the Deccan Plateau.
 Patches of shola grasslands that occur on hill slopes alongside
the extremely moist evergreen forests in South India.

 In some regions, grasslands also support a variety of
other herbaceous plants like sedges, legumes and
members of the sunflower family.
 Grasslands support numerous herbivores, from minute
insects to very large mammals.
 Rats, mice, rodents, deer, elephants, dogs, buffalo,
tigers, lions, ferrets are some common mammals of
grasslands.
 In northeast India, the one-horned rhinoceros is
amongst the threatened animal of grassland in this
region.

Economic Importance of Grasslands
• Grasslands are the grazing areas of many rural communities.
• Farmers who keep cattle or goats, as well as shepherds who keep sheep, are
highly dependent on grasslands.
• Domestic animals are grazed in the ‘common’ land of the village.
• Fodder is collected and stored to feed cattle when there is no grass left for them
to graze in summer.
• The grass is also used to thatch houses and farm sheds.
• The thorny bushes and branches of the few trees that are seen in grasslands are
used as a major source of fuelwood.
• Overgrazing by huge herds of domestic livestock has degraded many grasslands.
• Grasslands have diverse species of insects that pollinate crops.
• There are also predators of these insects such as small mammals like shrews,
reptiles like lizards, birds of prey, and amphibia such as frogs and toads.
• All these carnivorous animals help to control insect pests in adjoining
agricultural lands

Functions of Grassland Ecosystem
They perform certain functions. These
are:
Energy flow through the food
chain
Nutrient cycling
(biogeochemical cycles)
Ecological succession or
ecosystem development
Homeostasis (or cybernetic) or
feedback control mechanisms
To increase the fertility of the
soil and to regulate the
productivity of the ecosystem.

Threats of grassland ecosystem
• over gazing;
• using the wrong, and or too much fertilizer;
• not rotating land or applying seasonal approaches;
• not retaining multiple species;
• not understanding the soils and the soil water
relationship in each place;
• not grazing the right stock for the climatic conditions;
• not ploughing in many cases, as this can destroy soil
structure if done to often;
• using fire carefully to regenerate grasslands and reduce
incursion of shrubs - should be used sparingly

What effects if grassland disappear?

How to conserved grassland
ecosystem
• Overgrazing should be avoided or totally
stopped in severely degraded grassland.
• soil and water management in micro-
catchment hilly areas will help in restoration
of natural productive ecosystem.
• Fires must be prevented and controlled
rapidly.
• Pubic awareness.

DESERT ECOSYSTEM

DESERT ECOSYSTEM
• What is desert or Semi –arid ecosystem?
• Desert ecosystem is the community of living
and non-living organisms living together and
interacting in an environment which seems to
be abandoned.
• A Desert ecosystem is the interaction between
both the Biotic and Abiotic components of the
environment.

Structure of desert ecosystem

DESERT ECOSYSTEM CHARACTERISTICS
Aridity
• It is the common characteristic of all the deserts on the earth. Aridity simply
implies the deficiency of moisture’s or dryness. Desert experience very less
rainfall and thus result in aridity.
Less rainfall/ precipitation
• Less precipitation is one of the major features of deserts and also the reason
behind the dryness. The rainfall in deserts is seasonal and occurs only for a
limited duration. The annual rainfall that a desert receives every year is just 25-
30 centimeters.
Extreme temperature
• Desert ecosystems experience extreme temperatures during day and night. The
days are very hot and the nights can be extremely cold. It is the sole
characteristic of all the desert ecosystems either hot or cold all lacks moisture.
Velocity of wind
• It tends to be very high in a desert ecosystem. This is the reason deserts
experience sandstorms/ dust storms of high intensity resulting in the formation
of huge sand dunes. Surya Prabhahakar singh ( PSIT ; Kanpur)

Scarcity of water
 Due to less rainfall, there is a shortage of water in a desert
ecosystem.
 Due to the scarcity of water deserts have to face the
situation of drought half of the year.
The quality of the soil
 In deserts is very low to grow vegetation.
 It is dry, rocky, thin, sandy, mainly grey in colour
 no organic contents like nitrogen, phosphorus etc which
are essential for the growth of plants.

TYPES OF DESERT ECOSYSTEM
Desert ecosystems do not exist only in hot and dry areas of the earth. You can a find
a desert ecosystem in a tropical, arid, and even in extremely cold locations.
Here we have shared information about all the types of Desert Ecosystem that exist
on this earth.
Hot and dry
semi-arid
Hot and Dry Desert Ecosystem-
These kinds of the desert ecosystem have hot and dry climatic conditions through
the air and have very low annual rainfall. The hot desert ecosystem is basically
found in Central America, South Asia, North America, Africa, Australia etc. There are
extreme variations in temperature and soil is rough and harsh.
Semi-arid desert ecosystem-
This desert ecosystem is quite similar to the Hot and Dry desert ecosystem. This
kind of ecosystem has hard rocks, stable ground, less sand dunes. Temperature is
not as extreme as a hot and dry desert ecosystem. Great Basin is an example of
Semi-arid desert ecosystem. It receives a lot of rain as compared to the normal
desert’s ecosystem

Great Basin

WHY DESERT ECOSYSTEM IS IMPORTANT
FOR EARTH?
• It is usually considered as the waste and useless land.
However, the literal meaning of desert (Desertus- latin
word) is waste but the truth is a desert ecosystem is a
significant part of the earth like other ecosystems. No
matter they are dry, receives less rainfall, have less
biodiversity but they are a part of earth and help in
maintaining a balance.
• Desert ecosystem is habitat to various species of plants and
animals. These plants have adapted to survive in
an extreme environment.
• It is also important as they act as carbon sink which means
the bacteria in the sand helps to store the carbon dioxide
and prevent it from entering into the atmosphere.

Threats of desert ecosystem
• Growing human population and various
development activities have started affecting
these ecosystem.
• Natural character of several areas have been
altered due to extensive irrigation by canals
particularly the salination.
• The over- extraction of ground water.

How can be conserved it ?

What is an aquatic ecosystem?
 Aquatic ecology is the study of water based ecosystems.
 They are an area of water, in which ‘significant’ biological activity
can occur
 This definition excludes most groundwater systems . Aquatic
ecosystems can involve flowing or still water, and can be fresh or
saline

Components of aquatic ecosystem

Importance of aquatic ecosystems
• Biodiversity- Species richness/trophic structure
• Breeding- Breeding grounds for many species
• Buffer systems- Physical and chemical
• Sinks-Resting places for sediments and
chemicals
• Only part of the hydrological cycle

Characteristics of Aquatic Ecosystems
Factors such as temperature, sunlight, oxygen, and nutrients
determine which organisms live in which area of the water.
Three groups of aquatic organisms include:
• Plankton - mostly microscopic organisms that float or
drift freely in the water, and can be microscopic
animals(zooplankton) or microscopic plants
(phytoplankton).
• Nekton - are all organisms that swim actively in open
water, independent of currents.
• Benthos - are bottom-dwelling organisms of the sea or
ocean and are often attached to hard surfaces.

Pond ecosystem
Can form naturally where groundwater reaches the
Earth’s surface.
 Humans intentionally create artificial lakes by damming
flowing rivers and streams to use them for power,
irrigation, water storage, and recreation (reservoir).
 Structured into horizontal and vertical zones. The types
of organisms present depend on the amount of sunlight
available.
Range in size from just a few square meters to thousands
of square kilometers
Ponds may be seasonal, lasting just a couple of months
(such as sessile pools)
Lakes may exist for hundreds of years or more

How Nutrients Affect Lakes
• Eutrophication -increase in the amount of
nutrients, such as nitrates, in an aquatic
ecosystem.
• As the amount of plants and algae grow, the
number of bacteria feeding on the decaying
organisms also grows.
• These bacteria use the oxygen dissolved in the
lake’s waters. Eventually the reduced amount
of oxygen kills oxygen loving organisms

threats of aquatic ecosystem
• Natural Succession normal cycle of pond becoming forest
• Artificial Succession humans to water via fertilizer & sewage
causing succession to happen faster =EUTROPHICATION
• Water Pollution
• Excessive use of Fertilizers
• Industries

Pollution load — Four forms of pollutants can be distinguished-
Poisonous pollutants — Agrochemicals, metals , acids and phenol
cause mortality, if present in a high concentration and affect the
reproductive functionality of fish .
Suspended solids — it affects the respiratory processes and
secration of protective mucus making the fish susceptible to
infection of various pathogens.
Seewage and organic pollutants — They cause deoxygenation due
to eutrophication causing mortality in fishes.
Thermal pollution — It cause increase in ambient temperature
and reduce dissolved oxygen concentration leading to death of
some sensitive species

HOW CAN AQUATIC ECOSYSTEM BE
CONSERVED?
 Plantation of trees in the catchment area of water body prevent
soil erosion and subsequently reduce the problem of slitation in
water body resulting in better survival of aquatic organisms.
 Avoid the establishment of industeries, chemical plants and
thermal power plants near the water resources as their discharge
affect the ecology of water body resulted in loss of biodiversity.
 The World Resources Institute documents that the designation of
a particular species as threatened or endangered has historically
been the primary method of protecting the biodiversity.

 Regulatory measures must be taken on wastewater
discharge in the water body to conserve biological
diversity.
 Increasing public awareness is one of the most important
ways to conserve aquatic biodiversity. This can be
accomplished through educational programs, incentive
programs, and volunteer monitoring programs.
 Various organizations and conferences that research
biodiversity and associated conservation strategies help
to identify areas of future research, analyze current
trends in aquatic biodiversity

Ecological succession
• It is the process by which the mix of species and
habitat in an area changes over time.
• Gradually, these communities replace one
another until a “climax community”—like a
mature forest—is reached, or until a disturbance,
like a fire,or other factors occurs

Find its ……?????
 Biogeochemicals
 Phagotrophs
 Biotic community
 BOD and COD
 Eutrophication
 Solid waste management
 OTE
 Desertification
 SNG and CNG
 Jhum cultivation
 Sardar sarovar project
 Trophic level
 Cipko moment

evs UNIT-2nd ecosystem.pptx

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