Energy Flow Model
(I)Energy flow 1s always in one direction (from producers to consumers).
(ii) The amount of energy flow decreases with successive levels. It has been estimated that only 10 % energy is transferred from one trophic level to the next. Rest is lost as heat or in respiration. (0n an average, producers consume about 20% of the energy ln respiration. Herbivores use about 30 % energy, while carnivores use up to 60% of the energy in respiration).
Considering these two facts a model for energy flow in an ecosystem can be prepared.
Balance of Nature (Equilibrium in Ecosystem)
Ecosystem are perfectly balanced ecological units. The number of organism – trophic level depends upon the number of available individuals at lower level which as food. For example, a high population of frog (primary carnivore) would also sun a large population of snakes (secondary carnivore). A reduction in the population of frog would decrease the population ot snakes and this would also adversely affect the population of hawk (top carnivore which feed on snakes). Therefore, availability of food is the main factor which maintains the size of population and thereby maintains the balance of nature. This balance is dynamic and fluctuates Within a short range.