Energy flow in an Ecosystem
Intended
Learning Outcomes
At
the end of this Lecture, students will be able to
• Explain energy flow in the ecosystem
• Draw models of energy flow in the
ecosystem
• Explain Food chain
• Explain types of food chain
Content
• 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