Environmental Studies

1. Ecology & Ecosystem
Dr.P.Sindhu
Assistant Professor of History
Mannar Thirumalai Naicker College,
Pasumalai, Madurai
Tamil Nadu

2. Meaning:
• Ecology is a branch of science which deals with the
study of interrelationship between biotic and abiotic
components of nature as well as relationship among
the individual of the biotic components.

3. Definition:
1. According to Woodbury (1954), “Ecology is a science
which investigates organisms in relation to their
environment”.
2. E.P.Odum (1969) defined ecology as “the study of
structure and functions of nature”.
3. R.Margalef (1968) treated ecology as “study of
ecosystems”.

4. Classification of Ecology:
• The important sub-division of ecology are Animal
Ecology and Plant Ecology.
• It is also classified as, Autecology → the ecological
study of one spices of organism and Synecology →
Ecological studies of communities or entire eco-
system.

7. Classification of Ecology:
a)Habitat Ecology: Study of different habitats on
planets earth and their effects on the organisms
living there.
b)Community Ecology : Study of the local distribution
of animal in various habitats. Also, it is related with
the recognition and composition of community units,
and succession.
c) Population Ecology: This is known as Demonology.
The population ecology also deals with interactions
between populations of different species in
community.
d)Evolutionary Ecology: it is concerned with the
problems of niche segregation and speciation.

8. Habitat Ecology

9. Community Ecology

10. Population Ecology

11. e) Human Ecology: it studies the inter-relationship
between man and man along with the environment.
f) Applied Ecology: it is important sub-division of
Ecology. It deals with the practical aspect of ecology.
g) Eco-system Dynamics: it deals with the ecological
study of the process of soil formation, energy flow,
productivity, etc.
Production Ecology, Ecological Energetics, Chemical
Ecology, Palaeo Ecology, etc.

12. Human Ecology

13. Ecosystem
 An ecosystem is a community of living organism in
conjunction with the nonliving components of their
environment (things like air, water, soil) interacting
as a system.
 The word ecosystem coined by A.G.Tansley in 1935, -
“Life supporting system.
 Eco=Region of space where interacting live,
 System= formed by interacting organism.
Concept: Ecosystem are made up of abiotic and biotic
components, and these basic components are important
to nearly all types if ecosystem.

14. Structure
• Abiotic component
• The non-living factors are called the abiotic component. They
include the physical & chemical components. They are solar,
water, CO₂, temperature, humidity, pH, N, etc.

15. Biotic component
The living component of the environment comprises the
biotic components. It is classified into the following:
1. Producer or Autotrophs
2. Consumer
3. Decomposer

16. • Producer: They are capable of synthesizing their own organic
food from the simple inorganic substances in any ecosystem;
the producers are chlorophyll bearing photosynthetic
organisms. They convert the solar radiant energy into
chemical energy and synthesize carbohydrates.
• Examples: microscopic plants and the rooted or floating plants
in pond and lake, the algae in the ocean, the grasses in the
grass lands and trees in the forests are the producers in their
respective ecosystem.

17. Consumer
• Consumer are the living members of the ecosystem which
consume the food produced by the producers. The
consumers are again classified as primary, secondary and
tertiary consumers

18. Primary Consumer:
• The herbivores are the animals ( that eat only
plants). They depend upon the plants for their food
and survival and they are primary consumers in an
ecosystem.
Examples: Deer, Goat, Cattle, Rabbit.

19. Secondary Consumer:
• They feed on the primary consumers (herbivores). Since the
primary and secondary consumers are animals, the secondary
consumers are also called carnivores, which the animal eats
meat. The secondary consumer are the first level of animals
feeding on other animals and therefore they are also called as
primary carnivores. Examples : Cat, Fox, Snake

20. Tertiary Consumer:
• The secondary consumers are killed and fed by tertiary
consumers. The tertiary consumers are the second level of
animal feeding on other animals and are therefore called as
secondary consumers.
• Examples : Lion eats Wolf, Snake eats Frog, Bird and men eat
Fish

21. Decomposer or Transformer
• When plants and animals die, they become food for
decomposer like bacteria, fungi and earthworms (called as
microorganism). Decomposer recycle dead plant and animal
into chemical nutrients like carbon and nitrogen that are
released back into the soil, air, and water.

22. Functions:
• The abiotic and biotic components of the ecosystem
are interacting system and linked by energy,
nutrients and minerals.
The following are the functions of the ecosystem
1. Energy flow
2. Food Chain
3. Food Web

23. Energy Flow
• The main source of energy for an ecosystem is the light
energy from sunlight.
• Plant converts this light energy into chemical energy
sugar by the process of photosynthesis.
• Since plants can grow by converting the sun’s energy
directly into their tissues. They are known as
producers.
• The plants are used by herbivores as food, which gives
energy. A large part of this energy is used up for the
metabolic functions of these animals, such as
breathing, digesting food, supporting growth of
tissues, maintaining blood flow and body temperature.

24. Food Chain
• The transfer of energy from the source through a series of
organisms, by eating and being eaten, constitutes food chain.
Thus different plants and animals species are linked to one
another through food is called food chain.

25. Food Web
The food chains are not independent. The organism of one chain
may obtain food from more than one chain. Thus various food
chains are interconnected with each other. This interlocking of
many food chains is called food web. Each step of a food web is
called a tropic level.
Example A Food Web in a grassland ecosystem

26. Examples of Forest Ecosystem
• A forest ecosystem is a community of organisms
that lives within a forest. A forest is a natural
woodland unit consisting of all plants, animals and
microorganisms in that area functioning together
with all of the non-living physical factors of the
environment.
• A forest is usually defined as a large group of trees.
Nearly it occupies 40% of the land area. Amazon is
being a prime example.
• In India 19% of the land is occupied by the forest.
• Plant life and fungi and
• Many different animals, birds and insects.

29. Grassland Ecosystem
A grassland is a wide open grassy space. A grassland
may also contain low shrubs and other plants, but its
predominant features is that it is a place where plenty
of grass grows. These creatures can include various
types of grasses, insects and animals etc. In this
ecosystem we will find
1. Habitat
2. Soil Quality
3. Beauty
4. Useful to humans

31. Desert Ecosystem
• Desert ecosystem is a community of organism that
live together is an environment that seems to be
deserted wasteland.
• Deserts are areas of land that are arid, or dry, and
get less than 10 inches of rain per year.
• These areas can be covered by sand, rock, snow, and
even ice.
• Additionally, they do not have a lot of plant life
covering the land.
• Desert ecosystems covers approximately 25% - 30%
of the earth.

32. • An ecosystem includes all the life in a particular
environment or location.
• Deserts can be divided into two main types: hot and
cold.
• Many different animals, birds and insects.

34. Aquatic Ecosystem
• They are made up of plants and animals that live in
the water.
• These ecosystem differ in relation to the geographic
region where they exist and their proximity to the
land.
• Aquatic ecosystem can vary widely in size from an
ocean to a poll of water.
• There are also aquatic ecosystem of salt and fresh
water.
• This ecosystem is the largest because they represent
75%.
• Types of aquatic ecosystem : marine ecosystem,
freshwater ecosystem, pond ecosystem, lake
ecosystem and river ecosystem.