How do energetic considerations contribute to the structure

How do energetic considerations contribute to the structure of populations, communities,

and ecosystems?

Solution

Ecology deals with organisms,population,communities,ecosystem and the the biosphere.Population is defined as a group of individuals of any one kind of organism.A community includes all the populations of a given area.The community and the abiotic environment interact and function as a system called ecological system or ecosystem.Energy is the capacity to do work.For all biological activity,organisms require energy.THe energy ultimately comes from the sun.Solar energy is transformed to chemical enegy by the process of photosynthesis in the green plants.The consumers who are heterotrophs directly or indirectly depend on the green plants for their food.Therefore the energy flows from sun to plants and then to other heterotrophic organisms such as herbivores,carnivores.The flow of energy from autotrophs to heterotrophs is unidirectional.Therefore energy flow in ecosystems can be defined as\"unidirectional flow of energy from the sun to plants and then to all heterotrophic organisms in a non-cyclic manner.\"The energy flow through ecosystem obeys the two laws of thermodynamics.

1st law states that energy is neuther be created nor be destroyed,but is transformed from one state to other.

2nd law states that energy cannot be transferred cent percent from one form to another.Some amount of energy is lost during transfer from one form to the other.

example:-Electric energy is coonverted to light energy to illuminate the electric bulb.Total amount of electric energy spent for illumination of an electric bulb is not converted cent percent into light energy.A part of it is used for illumination of bulb and the rest is lost as heat energy produced by electric bulb.

It is estimated that 5*1000000 Kcal/m2/year amount of solar energy enters earth\'s atmosphere.Out of the total solar energy available to the plants,only 1-5% is used for photosynthesis and the rest is either radiated back or lost as a heat of evaporation. The total amount of chemical energy produced by green plants from solar energy is called gross primary productivity.Out of this some amount of energy is used by green plant itself for its metabolic process like respiration,repair,reproduction etc.And the balace that remains after metabolism is called net primary productivity.

Net primary production energy is available to the herbivores.Herbivores use sizable amount of this energy for their own metabolism such as respiration,reproduction,and repair.The balance that remains after metabolism is called secoondary production.IF in an ecosystem the net primary production is 100 calories the secondary production is 10 calories.Hence the amount of energy available with the carnivore is so little that there is no posibility of a further transfer of energy.