GE8291 CHAPTER2 ENERGY FLOW IN AN ECOSYSTEM

GE8291 CHAPTER2 ENERGY FLOW IN AN ECOSYSTEM

Energy is the most vital requirement for all living organisms.Solar energy is one of the source to our planet earth. Solar energy is transformed  into chemical energy in photosynthesis by the plants. 1% of sunlight that falls on green plants are utilized  for photosynthesis.

some amount of chemical energy is used by the plants for their growth and the remaining is transferred to consumers by eating. Thus the  energy enters the ecosystem through photosynthesis  and passes through the different tropic levels .

Energy flow through atmosphere to an ecosystem:

The ultimate source of energy is sun, its radiation travels through the space in the form of waves and reaches the earth’s atmosphere. Atmosphere absorbs 50% of  the radiation and allows the remaining to reach the earth surface, some of which is absorbed by the organisms (primary producers) to produce the organic matter through photosynthesis.

The  producers(plants) are used by the herbivores and the herbivores are used by the carnivores as their food. in this way the energy is transferred from one organism to another and so on. The  conversion of solar energy is governed by the laws of thermodynamics.

1st law of thermodynamics:

It states that,” energy can neither be created nor destroyed ,but  it can be converted from  one form to another.”

Energy for the ecosystem comes from the sun, which is absorbed by plants  where it is  converted into stored chemical energy.

Solar energy ————>Chemical energy(plants)

2nd law of thermodynamics:

It states that,“whenever energy is transformed, there is a loss of energy through the release of heat.”

This  occurs when energy is transferred between  tropic levels.There will be a loss of energy(about80-90%) in the form of heat as it moves from one tropic level to another tropic levels. This loss of energy takes place through running, hunting, respiration etc.

Respiration equation:

CH2O+O2———->CO2+H2O

The net production of biomass is only about 0.5% of the total incident radiation(3000K.cal/m^2/day) and 1.0% of energy absorbed and remaining gets wasted.

Relation between  structure and function :

The biotic  and abiotic components are linked together through energy flow and nutrient cycling.