Energy flow in an Ecosystem

Energy flow in an Ecosystem

Learning Outcomes

the end of this Lecture, students will be able to

• Explain energy flow in the ecosystem

• Draw models of energy flow in the

• Explain Food chain

• Explain types of food chain


• Energy flow in the ecosystem

• Models of energy flow in the ecosystem

• Food chain and food web

• Types of food chain

Energy flow
in an Ecosystem

• Biological activities requires energy
which ultimately comes from the sun. Solar energy is transformed into chemical
energy by a process of photosynthesis this energy is stored in plant tissue and
then transformed into heat energy during metabolic activities.

• Thus in biological world the energy flows
from the sun to plants and then to all heterotrophic organisms the flow of
energy is unidirectional and non-cyclic. This one way flow of energy is
governed by laws of thermodynamics which states that:

(a) Energy can neither be created nor be destroyed but may be
transformed from one form to another.

(b) During the energy transfer there is degradation of energy from a
concentrated form (mechanical, chemical, or electrical etc.)  to a dispersed form (heat).

• No energy transformation is 100 %
efficient, it is always accompanied by some dispersion or loss of energy in the
form heat. Therefore, biological systems