Jr. M.F.Sc. (Fisheries Resource Management)
College of Fisheries, Mangalore
Ecosystem: Defined area in which a community lives with
interactions taking place among the organisms between
the community and its non-living physical environment.
An ecosystem is formed by the interactions between all
living and non-living things
Ecosystem is the basic functional unit of ecology in which
include both living and non-living things
This term was introduced by Ernst
Haeckl in 1869.
The word ecosystem was coined by
Tansley, A.G. (1935).
What is an ecosystem?
System = Regularly interacting and interdependent
components forming a unified whole
Ecosystem = an ecological system;
= a community and its physical environment
treated together as a functional system
Components of an Ecosystem
Water or moisture
Soil or water chemistry
STRUCTURE OF AN ECOSYSTEM
TYPES OF AN ECOSYSTEM
– Terrestrial ecosystem
– Aquatic ecosystem
• Lentic, the ecosystem of a lake, pond or swamp.
• Lotic, the ecosystem of a river, stream or spring.
• Artificial, ecosystems created by humans.
A terrestrial ecosystem is an ecosystem found only on a landform.
Four primary terrestrial ecosystems exist: tundra, taiga, temperate
deciduous forest, and grassland.
• The two main types of aquatic ecosystems
are marine ecosystems and freshwater
• Marine ecosystems cover approximately 71%
of the Earth's surface and contain
approximately 97% of the planet's water.
• Freshwater ecosystems cover 0.80% of the
Earth's surface and inhabit 0.009% of its total
water. They generate nearly 3% of its net
• Lentic: slow-moving water,
including pools, ponds, and lakes.
• Lotic: rapidly-moving water, for
example streams and rivers.
Trophic level: All the organisms that are
the same number of food-chain steps from
the primary source of energy
• The trophic level interaction involves three
• Food Chain
• Food Web
• Ecological Pyramids
• The producers, consumers, and decomposers
of each ecosystem make up a food chain.
• There are many food chains in an ecosystem.
• Food chains show where energy is transferred
and not who eats whom.
Example of a Food Chain
• All the food chains in an area make up the food web of the area.
Food web of a hot spring
Food web of the harp seal.
Trophic Levels Found on an Energy
• The greatest amount of energy is found at the base of the
• The least amount of energy is found at top of the pyramid.
• Ecosystems are made up of abiotic (non-living,
environmental) and biotic components, and these
basic components are important to nearly all types
• Energy is continually input into an ecosystem in
the form of light energy, and some energy is lost
with each transfer to a higher trophic level.
• Energy is moved through an ecosystem via a food
web, which is made up of interlocking food
• Odum, E.P.(1971), Fundamental of Ecology, Principles
and concept pertaining to the ecosystem. pp 8-33.
• Odum, E.P.(1983), Basic ecology, The ecosystem, pp 1382.
• Shrivastava, C.B.L. (1999), A Text Book of Fisheries
Science and Inland Fisheries, Ecology of Aquatic
Ecosystem, pp 160-206.
• Jhingran, V.G. (1991), Fish and Fisheries of India, Fish
culture in fresh water pond, Ecology, pp 273-328