OUR ENVIRONMENT class 10 presentation full lesson explained

1. OUR ENVIRONMENT
ISHANI VISHWANATHAN

2. ECO-SYSTEM AND ITS COMPONENTS
FOOD CHAINS AND WEBS
HOW DO OUR ACTIVITIES AFFECT THE ENVIRONMENT?
OZONE LAYER AND ITS DEPLETION
MANAGING OUR GARBAGE PRODUCTION
OVERVIEW
Today's Agenda

3. ECOSYSTEMS
An ecosystem is a self-contained unit of
living things (plants, animals and
decomposers), and their non-living
environment (soil, air and water).
The examples of ecosystems are grassland
(meadow), a forest, a desert, a mountain, a
pond, a lake, a river and a sea.
Most of the ecosystem in the world are
natural ecosystems but some of them are
also man-made ecosystems or artificial
ecosystems.
Artificial ecosystem includes crop-fields
(agriculture lands), parks and aquarium.
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4. A POND IS AN
ECOSYSTEM
Can anyone give me an answer
why?
Ponds are water bodies that are shallow,
hence sunlight reaches till the bottom
facilitating plant growth there. It offers
components of a good ecosystem such as
biotic factors (aquatic insects, fishes,
phytoplanktons and microbes) as well as
abiotic factors (water, soil, air, light, etc).

5. COMPONENTS FUNCTIONING
PRODUCERS,
CONSUMERS
AND
DECOMPOSERS

6. ABIOTIC
COMPONENTS
The abiotic components (or non-living components) of an ecosystem
include the physical environment like soil, water and air alongwith the
inorganic substances like carbon dioxide, nitrogen, oxygen, water,
phosphorus, sulphur, sodium, potassium, calcium and other elements
present in them.
The physical factors or climate factors like light, temperature, pressure
and humidity are also considered abiotic components of the ecosystem.

7. The biotic components (or living components) of an ecosystem is a
community of organisms (like plants and animals), which is made up of
many different inter-dependent populations.
The biotic community (or living world) of an ecosystem includes three
types of organisms:-
Producer organisms (or Autotrophs)
Consumer organisms (or Heterotrophs)
Decomposers (or Saprotrophs)
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BIOTIC COMPONENTS

8. Ecosystem functions as a self-sufficient or independent unit in nature. Ecosystem has both living and
non-living components. All these components make the ecosystem functions as follows: From the
nutrient pool of the earth (soil, water and air), carbon dioxide and water are absorbed by the producer
organism (green plants). With the help of sunlight energy, the producer organisms convert these
inorganic substances into organic compounds like carbohydrates which act as a food. Thus, producers
trap the solar energy and then provide the basic food or energy for all other life forms in the ecosystem.
The consumers (animals) derive their energy needs, directly or indirectly, from the producers (plants).
When the producers (plants) and consumers (animals) die, then the decomposer organisms act on
their dead bodies to return the various elements back to the nutrient pool (soil, water and air). Thus, an
ecosystem involves input of energy and matter which are exchanged between living and non-living
components in a cyclic process.
FUNCTIONING OF
ECOSYSTEM

9. Let's Discuss and
Analyze Together

10. Producers are the organisms which can
prepare their own food from simple inorganic
substances like carbon dioxide and water by
using sunlight energy in the presence of
chlorophyll.
The examples of producers are green plants
and certain blue-green algae.
PRODUCERS

11. Those organisms which consume food prepared by producers are called
consumers.
All the animals are consumers.
If an animal eats grass or other green plants or their products itself we say
that it gets the food from producers directly.
If an animal eats the meat of another animal (which eats grass), then we say
that it gets the food from producer indirectly.
Consumers can be further classified as herbivores, carnivores and omnivores.
CONSUMERS

12. Herbivores feed directly on plants. Herbivores are primary consumers. The
herbivores may eat grasses, leaves, grains, fruits or the bark of trees. (Deer,
Elephant, Squirrel)
Carnivores feed on the flesh of animals. Those animals which eat only other
animals as food are called carnivores. The carnivores eat the meat (or flesh) of
other animals. (Lion, Tiger, Vulture)
Those animals which eat both, plants and animals, are called omnivores. Man is
called an omnivore because he eats both, plant food (such as grains, pulses, fruits
and vegetables) as well as meat of animals (such as goat, chicken and fish).
HERBIVORES, CARNIVORES
AND OMNIVORES

13. Planktons are very minute or microscopic organisms freely
floating don the surface of water in a pond, lake, river or
ocean.
Planktons are of two types: Phytoplankton and
Zooplanktons.
The microscopic aquatic plants freely floating on the surface
of water are called phytoplanktons.
Eg: Algae
The microscopic aquatic animals freely floating on water are
called zooplanktons.
Eg: Protozoa
PLANKTON

14. DECOMPOSERS
The micro-organisms which break
down the complex organic
compounds present in dead
organisms like dead plants and
animals and their products like
faeces, urine, etc., into simpler
substances are called decomposers.
The bacteria and fungi act as decomposers by
the secretions of their body surfaces which
decompose the organic matter present in dead
plants and animals into simpler substances
and liberate ammonia, carbon dioxide, etc..
The bacteria which act as decomposers are
called putrefying bacteria.
Decomposers help in the
recycling of materials in
ecosystem. The decomposers are
also known as micro-consumers
or Saprotrophs.

15. DO YOU HAVE
QUESTIONS SO FAR?
Feel free to make this an open discussion for
questions or clarifications before proceeding.

16. Food chains and webs
A food chain is the flow of food energy from one organism to the next and to the
next and so on. They usually start with a producer (plants) and end with a
carnivore. In a food chain an organism gets food from one group of organisms.
What is a food chain?

17. Food chains and webs

18. Features of food chain
Producers based : All sustainable food chains are producer based.
Energy : Producers obtain energy from sun. All others (consumers) obtain the energy from food
originally built up producers. There is unidirectional flow of energy.
Biogenetic Nutrients : Inorganic nutrients must keep on circulating with the help of decomposers.
Otherwise, food chains cannot be sustained.
Straight : Unless linked with another, food chain runs straight.
Size : Food chains are generally short with 3-5 trophic levels.
Populations : Size of populations decreases with the rise in trophic level. Top carnivores are always
very few.
Operation at different trophic levels : An organism can operate at more than one trophic level, e.g.,
snake feeds on herbivorous rat as well as carnivorous frog.

19. Importance of food chain
Food chains provide pathway for passage of food and energy
distribution .
They provide information about the living components of
the ecosystem
Food chain indicates the interactions and interdependence
among the different organisms.
The effect of reduction or or increase in the population at a
trophic level can be known.

20. Food Webs
Food web is a connection of several interconnected food chains. In a food web an organism gets food
from more than one group of organisms.

21. Features of food Webs
It doesn’t allow any population to starve.
It does not allow species to grow as an increased
availability. It doesn’t allow any species to overgrow.
It allows endangered population to grow in size.
It provides stability to ecosystem.

22. Each step in a food chain where transfer of food
energy takes place is called trophic level.
The first trophic level consists of producers.
The second trophic level consists of primary
consumers.
The third trophic level consists of secondary
consumers.
The fourth trophic level consists of tertiary
consumers.
Since the transfer of food energy decreases at every
trophic level, the number of trophic levels are
limited and do not exceed four or five.
Trophic levels :-

23. Green plants (producers) absorb about 1% of
solar energy falling on the leaves and stores it
as food energy during photosynthesis.
During the transfer of food energy from one
trophic level to the next, 90% of the energy is
lost to the environment and only 10% is
transferred to the next trophic level. So there
is a decrease in the amount of food energy
transferred at every trophic level by 10%. This
is known as the 10% law.
Energy Flow In Trophic
levels :-

24. Harmful chemicals like insecticides and pesticides which are used to protect crops from insects
and pests are absorbed by plants and enter the food chain. Since these chemicals are non
biodegradable, they get accumulated at every trophic level and their concentration increases.
Since human beings occupy the highest trophic level, the concentration of these harmful
chemicals is maximum in our bodies.
The increase in concentration of harmful chemicals in the bodies of organisms at higher trophic
levels is called biological magnification.
Biological magnification
(Biomagnification) :-

25. DO YOU HAVE
QUESTIONS SO FAR?
Feel free to make this an open discussion for
questions or clarifications before proceeding.

26. HUMAN ACTIVITIES AFFECT THE
ENVIRONMENT
Humans impact the physical environment in
many ways: overpopulation, pollution,
burning fossil fuels, and deforestation.
Changes like these have triggered climate
change, soil erosion, poor air quality, and
undrinkable water. These negative impacts
can affect human behavior and can prompt
mass migrations or battles over clean water.
We shall be looking at two of the
environmental problems in detail, that is,
depletion of the ozone layer and waste
disposal.

27. Ozone molecule contains three oxygen atoms (O3). At higher levels in the atmosphere
the UV radiation splits some oxygen molecules (O2) into free oxygen atoms which
combines with oxygen molecules (O2) to form ozone. It is highly poisonous.
Depletion of ozone layer
in the atmosphere :-
The ozone layer present in the higher layer of the atmosphere protects the earth from
the harmful UV radiation from the sun. UV radiation causes skin cancer in humans.
The ozone layer is being damaged by the use of chemicals like chloro fluoro carbons
(CFCs) used in refrigerators and fire extinguishers. So the use of CFCs is now being
reduced to protect the ozone layer.

29. i) Land fills
ii) Recycling
iii) Production of biogas and manure
iv) Preparation of compost
v) Incineration
vi) Sewage treatment
The household waste is called garbage. Some of the garbage is biodegradable and some are
non biodegradable. Garbage causes pollution of air, water and soil. So it should be disposed
properly.
Some of the methods of garbage disposal are :-
Managing the garbage
we produce :-

31. A biodegradable material can be defined as a material which can be decomposed by bacteria
or other natural organisms and not be adding to pollution.
Biodegradable wastes are such waste materials which are and can be degraded by natural
factors like microbes (e.g. bacteria, fungi and few more), abiotic elements like temperature,
UV, oxygen, etc. Some examples of such wastes are food materials, kitchen wastes, and other
natural wastes.
A Non-Biodegradable material can be defined as a kind of substance which cannot be broken
down by natural organisms and acts as a source of pollution.
Unlike biodegradable wastes, non-biodegradable cannot be easily handled. Non-
biodegradable wastes are those who cannot be decomposed or dissolved by natural agents.
They remain on earth for thousands of years without any degradation. A notable example is
the plastics which are a commonly used material in almost every field. To give these plastics a
long lasting effect, improved quality plastics are being put to use. This made them more
temperature resistant and more durable even after use. Other examples are cans, metals, and
chemicals for agricultural and industrial purposes.

32. Improvements in our life-style have resulted in
greater amounts of waste material generation.
Changes in attitude also have a role to play,
with more and more things we use becoming
disposable. Changes in packaging have
resulted in much of our waste becoming
nonbiodegradable. How has that impacted our
environment?
Class Discussion

33. RECAP OF TODAY'S CLASS
The various components of an ecosystem are interdependent.
The producers make the energy from sunlight available to the rest of the ecosystem.
There is a loss of energy as we go from one trophic level to the next, this limits the number of
trophic levels in a food-chain.
Human activities have an impact on the environment.
he use of chemicals like CFCs has endangered the ozone layer. Since the ozone layer protects
against the ultraviolet radiation from the Sun, this could damage the environment.
The waste we generate may be biodegradable or non-biodegradable.
The disposal of the waste we generate is causing serious environmental problems.

34. THANK YOU!
Done By Ishani Vishwanathan