Question

write a full paragraph in your own words, at least 150 words about:

Energy Flow

Answer 1

Energy flow is the key function in the ecosystem.The storage and expenditure of the energy in the ecosystem is based on two basic laws of thermodynamics.The first law of thermodynamics states that when energy is converted from one form into another,energy is neither created nor destroyed,energy is neither gained nor lost.The first law is also called the law of conservation of energy.The second law of thermodynamics states that every transformation results in a reduction of the free energy of the system.Energy transformation cannot be 100% efficient(second law).The operation of an ecosystem ,is consistent with the laws of thermodynamics that deal with the relationships between energy and matter in a system.First,we can account for the total energy input to an ecosystem in budgetary fashion.This is consistent with the first law of thermodynamics.Energy may change form but not amount.But as the energy moves through an ecosystem,it does change form,ultimately to heat,which is not directly usable by the system.Thus the system tends to run down,dissipating its energy and losing its organized structure.This is the nature of the second law of thermodynamics,a tendency toward maximum disorganization of structures and maximum dissipation of usable energy.

GENERAL PRINCIPLES OF ENERGY FLOW

The behaviour of energy in ecosystems is reffered to as energy flow because energy transformations are directional,in contrast to the cyclical behaviour of nutrients.The conversion of solar radiation to chemical energy by photosynthesis is the starting point of energy flow within ecosystems.Solar energy is transformed from the radiant to the chemical form in photosynthesis and from the chemical to mechanical and heat forms in cellular metabolism.These conversions and sequences are fundamental to the energetics of organisms and ecosystems as energy passes into and through producers,to and through consumers and decomposers.Only about 1-5% energy of incident radiation,or 2-10% of PAR(photosynthetically active radiation)is actually captured by the photosynthetic process(gross primary productivity),and the remaining portion is dissipated.Since the simultaneously occuring respiratory processes are energy consuming and use up part of the photosynthetic gain,the net capture of energy(net primary productivity is reduced to only 0.8-4 % of incident total radiation,or 1.6-8% of PAR.Only the energy captured in net productivity of producers can be used only by other trophic levels.

It can be concluded that only 10% of energy is transferred to each trophic level.(10 percent law).