destroyed, but can be transferred from one from to other.
(B) Second law : It states, that every energy change involves the
degradation or dissipation of energy,
from concentrated to the dispersed form due to metabolic functions,
so that only a small part of energy is stored in the biomass.
(iii) Nutrient cycles : All living organisms get matter from
the biosphere component i.e. lithosphere, hydrosphere and
atmosphere. Essential elements or inorganic substances are provided
by earth and are required by organisms for their body building and
metabolism, they are known as biogeochemical or biogenetic
nutrients.
(iv)Development and stabilization : This function is
necessary for the development and giving stability to various life
form’s by undergoing certain modifications.
15.2 FOOD CHAIN :
- The chain of organisms which involves transfer of energy
from one trophic level to next trophic level is called as food chain. - The flow of food or energy is an ecosystem is called Food
chain. Those organisms which join with the food chain are termed
as Trophic levels. - Usually, there are four trophic levels present in the
ecosystem because level of energy decreases during the flow of
energy from one trophic level to the another trophic level.
First trophic level [T 1 ] : Producers
Second trophic level [T 2 ] : Primary consumers
Third trophic level [T 3 ] : Secondary consumers
Fourth trophic level [T 4 ] : Top consumers - The flow of energy occurs in an ecosystem from the first
trophic level to the fourth trophic level in the food chain. These are
five trophic levels also found in a highly complex ecosystem in
which tertiary consumers are present in between the secondary
consumer and top consumers, then fifth trophic level (T 5 ) formed by
the top consumers.