This document defines an ecosystem as the integration of all living and non-living factors in an environment. It describes the key characteristics of ecosystems, including that their structure relates to species diversity and function relates to energy flow and material cycling. Ecosystems are classified as either natural or artificial/man-made, and include terrestrial, aquatic, marine, and other types. The components of ecosystems include biotic factors like producers, consumers, parasites and decomposers, and abiotic factors like inorganic substances, organic substances, and climate. Food chains and trophic levels are also summarized, where energy transfers from producers to various consumer levels, and food chains interconnect to form food webs.

3. Sir Arthur G Tansley (1935) coined the term
ecosystem and defined it as
“the system resulting from the integration of all living
and non-living factors of the environment”.

4. CHARACTERISTICS OF ECOSYSTEM
 Major structural and functional unit of ecology.
 Structure of an ecosystem is related to its species diversity.
 The function of ecosystem is related to energy flow and material cycling
through and within the system.
 The relative amount of energy needed to maintain an ecosystem depends on
its structure.
 Both the environment and the energy fixation in any given ecosystem are
limited and cannot be exceeded without causing serious undesirable effects.

5. TYPES OF ECOSYSTEM
The whole earth constitute the Giant ecosystem called
biosphere. It has been further divided either on the basis of
habits or on the basis of spatial scale, user sources and level
of energy, stage of ecosystem development, stability or
instability

6. ECOSYSTEM
Terrestrial Aquatic
Natural Artificial(man made ecosystem)
Crop field Garden
Mountain
Grassland
Forest
Tundra
Desert
Cold desert
Warm desert

7. ECOSYSTEM
Terrestrial Aquatic
Natural Artificial(man made ecosystem)
Aquarium sewage
Marine
Coastal /
Estuarine
Coral reef
Flowing Still water
Fresh water
Ocean
River
Stream

8. COMPONENTS OF ECOSYSTEM
Biotic components – living parts Abiotic components – non living parts

9. Biotic component
Important part of ecosystem in which energy flows in the form of food
from one organism to another organism with in a community divided
into four
1.Producer
Green plants which synthesis their on food by the process – photosynthesis
2.Consumers
Heterotrophic organisms which directly or indirectly depend on producers for energy is procured
in the form of food.
a. Primary consumers – herbivores which depend upon green plants for their food
E.g.: cow, goat, rabbit, some insects.
b. Secondary consumer- carnivores that use herbivores as their source of food
E.g.: snake, frog. Etc.
c. Tertiary consumers – top consumers and their kill and eat the secondary / primary consumers.
E.g.: lion , tiger etc.

10. 3.Parasites
which obtain their food directly from living organism.
detritivores or scavengers- are small animals , which feed on dead bodies of
other organisms such as termites.
4. Decomposer
which decompose the dead organism , such as bacteria and fungi.
Microconsumer –these decompose organic complexes Into simple substance,
which are either mixed with in the soil or evaporated in the atmosphere
produces , consumers and decomposes remain linked together by food chain .

11. Abiotic component
1. Inorganic substances
includes elements (minerals), water , gas etc. which are required for
the synthesis of organic substance by the producers. These keep on
circulating within the ecosystem.
2. Organic substance
are derived from dead plants and animals as well as from their excreta.
Such substances are decomposed to realized the minerals.
3. Climate
include the factors like rain , heat , light , temperature , humidity , wind etc.
the interaction of various climatic factors determines the nature of ecosystem

12. Transfer of food energy from the source in plants through a series of
organisms with repeated eating and being eaten is refer to an food
chain.
Tropic levels :-
The successive levels of energy flow constituting the links of the food chain.
The first tropic level in a food chain is produces or green plants.
Second level of tropic level are primary consumers or herbivorous which feed up on
the green plants for their nutrition. Smaller carnivorous organisms which prey upon
herbivorous to obtain their foods from the third tropic level and called secondary
consumers. The large carnivores which pray upon secondary consumers to obtain
their food is known as tertiary or top consumers
Food chain

14. FOOD WEB
A net work of food chain is found and these interconnected food
chain form a structure called food web. The food webs become more
complicated because of variation in the taste and preference,
availability and compulsion and several circumstancial factors.