This chapter discusses key topics related to ecosystems and the environment, including different types of waste and their effects; components and types of ecosystems; trophic levels and how energy flows between them; food chains and webs; and how human activities can impact the natural environment. Biodegradable waste can decompose and cause smells or disease if used in large quantities, while non-biodegradable waste pollutes land and water. Ecosystems contain biotic factors like producers, consumers, and decomposers, as well as abiotic factors that influence biodiversity. Energy is transferred between trophic levels and concentrated upwards, while human activities like CFC emissions can deplete the ozone layer.

1. Our Environment
Chapter 15

2. Topics to be studied in this chapter
❖ Waste types and their effects on our environment
➢ Biodegradable substances and their effects
➢ Non-biodegradable substances and their effects
❖ Ecosystem
➢ Types of ecosystem
➢ Components of ecosystem
❖ Trophic levels
❖ Food chain
➢ Types of food chains
➢ Significance of food chain
❖ Food web
❖ Energy flow
❖ Biomagnification
❖ Human impact on the natural environment

3. Waste types and their effects
Biodegradable waste and their effects
The substances that can be eaten up or can be decomposed by
the action of microorganism are called biodegradable waste
EFFECTS
If we use it on large scale then. . . . .
1. Decomposition leads to foul or bad smell
2. Breeding of flies on a large scale on this waste leads
to spread of diseases

4. Waste types and their effects
Non-Biodegradable waste and their effects
The substances that cannot be converted into harmless simpler
substances by the action of microorganisms are called non-
biodegradable waste
EFFECTS
1. They pollute the water and land and harm all the organism
2. Radioactive waste cannot be decomposed and causes life
threatening disease in all the organisms

5. 1. Natural ecosystem
The natural existing ecosystem
without any human support is called
natural ecosystem.
Depending on the habitats the
ecosystems can be terrestrial and
aquatic.
terrestrial=desert,grassland,etc.
aquatic=marine life
Types of ecosystem
2. Artificial ecosystem
An ecosystem which is created and
maintained by humans is called
artificial or man-made ecosystem.
These rely on human efforts it
sustain.it does not possess a self
regulating

6. Components of ecosystem
1. Biotic components
Biotic components include all the living organisms
present in the ecosystem On the basis of their
nutritional Requirement these are classified in
Three groups i.e.
1. Producers
2. Consumers
3. Decomposers

7. 1. Producers = all green plants and certain blue green algae
which can produce food by the process of photosynthesis
are producers these are also called autotrophs.
2. Consumers = they are dependent on other organisms for
their nutritional requirements and consume food of other
organisms producers thus they are called consumers .
3. Decomposers = these are microorganisms which feed on dead
and decaying organic matter they breakdown the remains of
dead animals and plants to releases various substances
that can be used by other members of the ecosystem .

8. Components of ecosystem
1. Abiotic components
The abiotic components of an ecosystem are the non-living
components on which living organisms are dependent each
abiotic component influences the number and variety of
plants and animals present in an Ecosystem this in turn
influence the Biodiversity of an area

9. Trophic levels
The transfer of food or energy takes place through various
steps or levels in the food chain known as trophic levels .
the producers are present at the first trophic level.they fix
solar energy making it available for consumers.the herbivores
or the primary consumers are found at the second trophic
level . Small carnivores or secondary consumers are present
at the third trophic level . the large or the tertiary
consumers form the fourth trophic level

11. Food chain
It is a linear network of living organisms in a community
through which energy is transferred in the form of food it
describes relationship of organisms about ‘WHO EATS WHOM’

12. Food chain
Types of food chain
1. Terrestrial food chain
Is present on land
2. Aquatic food chain
Is present in water
bodies
Significance of food chain
Food chain involves the transfer of
energy,materials and nutrients the
organisms of food chain serves as
the vehicles of transfer of energy
from one level to another

13. Food web
It is the interconnection of different food chains which
correlate at various trophic levels operating in an ecosystem
each organism is generally eaten by two or more other kinds
of organisms they in turn are eaten by several other
organisms so instead of a straight line the relationship is
shown as a series of branching lines hence creating a food
web.

15. Energy flow
Energy is accumulated by the primary producers and is
transferred through food chain to different trophic levels
this phenomenon is called energy flow
It is unidirectional and there is no recycling to previous
level whenever energy is transferred from one for to another
only 10% of the whole energy is transferred
And in case of poison it increases by every trophic level

16. Biomagnification
It is the phenomenon of progressive increase in the
concentration of non biodegradable toxicants in organisms at
each successive trophic level

17. Human impact on natural environment
Human are an integral part of the environment any change in
environment also affects us various human activities pollute
the environment in various ways and pose serious
environmental threats
Ozone depletion is the common impact of humans on the
environment
Ozone protects us from harmful UV rays by the reaction
between oxygen and the UV rays . O2 reacts with UV to form O
then O reacts with O2 to form O3 that is ozone

18. Due to the environmental pollution ozone layer has began to
deplete in the 1980s
This was mainly due to the increasing use of synthetic
chemicals like chlorofluorocarbons these are used in
refrigerants as coolant and in fire extinguishers
CFC is very stable it persist in the atmosphere and it does
not degrade easily
The united nations environment programme (UNEP)succeeded in
forming an agreement to stop the production of the CFC