Question

Define ecosystem. Draw a block diagram to show the flow of energy in an ecosystem.

Answer 1

Hint: Ecosystem = Eco (Ecology) + System (interaction unit). Living organism and its environment form a functional basic unit called ecosystem.

Complete step by step answer: Ecosystem is the ecological system or unit where all living and nonliving factors interact with each other and with their own components. The term ecosystem was given by G.Tansley. Living factors are biotic components and non-living factors are abiotic components. These biotic and abiotic components form the basic structure of the ecosystem. The abiotic component includes inorganic nutrients, organic compounds, climatic factors, etc. and biotic components include living organisms like plants, animals and microorganisms. The function of the ecosystem is related to the flow of energy and cycling of materials through its structural components. The ecosystem may be of temporary nature like a pond, cropland or permanent nature like an ocean or forest.
The ecosystem is simply separated from each other with time and space, but functionally they are linked together and there are no such functional boundaries between them. Physical factors and climatic conditions vary widely from place to place and thus, greatly affect the distribution of organisms.
Energy flow in the ecosystem:
The ultimate source of energy on our solar system is the sun. The producers (autotrophic organisms) make their food using solar radiation through photosynthesis. The food produced by the producers is consumed by the consumers at a different level. Energy is passed from one organism to another in the form of food.

Primary
Consumers
(1000 J)
       $\downarrow$
Secondary
Consumer
(100 J)
       $\downarrow$
Tertiary
Consumer
(10 J)

Note: The flow of energy from one level to another causes $90\mathrm{\%}$ loss of energy (in the form of respiration and heat) and this results in an inflow of only $10\mathrm{\%}$energy. This is called Lindmann’s $10\mathrm{\%}$law. The flow of energy is unidirectional, i.e. the energy trapped by autotrophs move from one level to the other but never revert back to its previous level.