1. CHAPTER 1 BASIC CONCEPTS OF ECOLOGY

3. Ecology—the scientific study of interactions between different organisms and between organisms and their environment or surroundings

4. ECOLOGICAL ORGANISATION
SPECIES
POPULATION
COMMUNITY
ECOSYSTEM
BIOME
BIOSPHERE

5. SPECIES THE MOST FUNDAMENTAL UNIT OF BIOLOGICAL ORGANISATION
IT IS DEFINED AS
A group of organisms that are capable of breeding with each other under natural conditions

6. POPULATION
A group of organisms of the same species that occupy a particular area over a given interval of time.
The size and extent of populations is described in terms of density i. e. no of individuals per unit area

7. COMMUNITY
Populations of various species living in the same area, representing a large no. of connections and needs are referred as community.
Within a community, each organism is found in a specific location.
Communities can change over long periods of time

8. ECOSYSTEMS
It is a self sustaining structural and functional unit of the biosphere.
The biotic community and abiotic elements of a particular area interacting and functioning as a unit is called the ecosystem.

9. BIOSPHERE
The portion of earth that supports life is called the biosphere.
Thebiosphere extends several km up in the atmosphere to the deepest parts of the oceans.

10. BIODIVERSITY
Biodiversity is variety of life and its processes. It consists of the variety of living organisms, having the genetic differences between them and the communities and ecosystems in which they occur.

11. TYPES OF BIODIVERSITY GENETIC DIVERSITY SPECIES DIVERSITY
ECOlLOGICAL DIVERSITY

12. GENETIC BIODIVERSITY It is the foundation of all biodiversities.
It is the variation in genes that exists within the species.
Genes make individuals of the same species look different from each other.
Genetic variations allow populations to get used to changing environments.

13. SPECIES BIODIVERSITY
It is the most commonly used representation of ecological diversity.
It refers to the no. of different species of all types in a giver area or region.
Different species have different roles to play within ecosystems.
To remain healthy, most ecosystems require thousands of different species making up their food webs.

14. ECOLOGICAL BIODIVERSITY
It is the diversity of ecosystems, natural communities and habitats.
It is the variety of ways that species interact with each other and their environment.

15. ECOSYSTEM

16. Ecosystem is the basic functional unit of ecology.
The term ecosystem is coined form a Greek word meaning study of home.
Definition
A group of organisms interacting among themselves and with environment is known as ecosystem. Thus an ecosystem is a community of different species interacting with one another and with their non living environment and one another and with their
non- living environment exchanging energy and matter.
Example
Animals cannot synthesis their food directly
but depend on the plants either directly or indirectly.

17. COMPONENTS OF ECOSYSTEM
An ecosystem has two major components
Biotic components
The living organisms (or) living members in an ecosystem collectively form its community
called biotic components.
Examples
Plants (producers), animals (consumers), and microorganisms (decomposers).
Abiotic components
The non-living surroundings
Examples Sun, Rain

18. Biotic—living factors that influence an ecosystem
Abiotic—non-living factors that influence an ecosystem

19. BIOTIC COMONENTS
The living organisms (or) living members in an ecosystem collectively form its community
called biotic components.

20. Classification of Biotic Components
The members of biotic components of an ecosystem are grouped in to three based on how they get food
(1) Producer (plants)
(2) Consumer (Animals)
(3) Decomposers (Micro-organisms)

21. Producers A. Sunlight is the main energy source for life on earth
Also called autotrophs
C. Use light or chemical
energy to make food
1. Plants
2. plant-like protists (algae)
3. Bacteria

22. (Remember: 6CO2 + 6H2O 6O2 + C6H12O6)
D. Photosynthesis—use light energy to convert carbon dioxide and water into oxygen and carbohydrates
(Remember: 6CO2 + 6H2O O2 + C6H12O6)
E. Chemosynthesis—performed by bacteria, use chemical energy to produce carbohydrates
Light Energy

23. Consumers (heterotrophs)
Organisms that rely on other organisms for their energy and food supply. Also called heterotrophs

24. Classification of consumers
Consumers are further classified as
(i) Primary consumers (Herbivores) (Plant eaters)
Primary consumers are also called herbivores,
they directly depend
on the plants for their food. So they are called plant eaters.
Examples :
Insects, rat, goat, deer, cow, horse, etc.,

25. Classification of consumers
(ii)Secondary consumers (primary carnivores) (meat eater)
Secondary consumers are primary carnivores, they feed on primary consumers.
They directly depend on the herbivores for their food.
Example
Frog, cat, snakes, foxes, etc.,
(iii) Tertiary consumers (Secondary carnivores) (Meateaters)
Teritary consumers are secondary carnivores, they feed on secondary consumers.
They depend on the primary carnivores for their food.
Examples
Tigers, lions, etc.,

26. Herbivores—obtain energy by eating only plants
Carnivores—eat only animals

27. Decomposers
Decomposers attack the dead bodies of producers and consumers and decompose
them into simpler compounds.
During the decomposition inorganic nutrients are released.
The inorganic nutrients together with other organic substances are then utilized by the procedures for the synthesis of their own food.
Example Microorganisms like bacteria and fungi.

28. Omnivores—eat both plants and animals
Decomposers—breaks down dead organic matter

29. ABIOTIC COMPONENTS Abiotic (non-living) components
The non-living components (physical and chemical)
of ecosystem collectively form a community called abiotic components (or) abiotic community.
Examples
Climate, soil, water , air, energy, nutrients, etc.,

30. ABIOTIC COMPONENTS 1. Physical components
They include the energy, climate, raw materials and
living space that the biological
community needs. They are useful for the growth and
maintenance of its member.
Example
Air, water, soil, sunlight, etc.,

31. ABIOTIC COMPONENTS 2. Chemical Components
They are the sources of essential nutrients
Examples
Organic substances : Protein, lipids, carbohydrates, etc., (ii) Inorganic substances:
All micro (Al, Co, Zu, Cu) and macro elements (C,H, O, P, N, P, K) and few other elements.

32. FUNCTION OF AN ECOSYSTEM
To understand clearly the nature of ecosystem its functioning should be thoroughly understood.
The function of an ecosystem is to allow flow of energy and cycling of nutrients.

33. FOOD CHAIN
The sequential inter-linking of organisms involve the transfer of food energy from the sun, through a series of organisms with respected eating and being eaten is reffered as food chain.

34. CHARACTERISTICS OF FOOD CHAIN
1. It involves a nutritive interaction between the living organisms of an ecosystem.
2. It is always straight.
3. It proceeds in a progressive straight line.
4. Flow of energy is unidirectional from sun to producers and consumers.
% of energy is lost as heat at each transfer.

35. FOOD WEB
Food web is a network of food chain which become inter-connected at various tropic levels so as to form a number of feeding connections amongst different organisms of a biotic community.

36. CHARACTERISTICS OF FOOD WEB
1. Food webs are never straight.
2. Food webs is formed by interlinking of food chains.
3. Food web provides alternative ways of food availability.
4. Food webs help in checking the overpopulation of organism .

37. ENERGY PYRAMIDS
A graphical representation of the tropic levels by which the incoming solar energy is transferred into an ecosystem.
The consumers are at the top of the food pyramid where as producers are at the bottom of the pyramid.

38. Sustainability The key concept for our future:
Limiting human impact on the natural world so that our civilization can continue to exist

39. Sustainable development
UN: Development that “meets the needs of the present without sacrificing the ability of future generations to meet theirs”.
Figure 1.17

40. Challenges We live on a planetary island with limited resources.
Population and consumption are growing.
Many feel that we have not yet developed the ethical basis for sustainability.
Environmental justice remains a challenge.