The document discusses energy flow through ecosystems. It makes three key points: 1) The largest source of energy for ecosystems is the sun. Plants absorb sunlight through photosynthesis which begins the process of energy transfer. 2) Energy and nutrients are passed between organisms as one eats another, forming food chains and webs. Typically only about 10% of energy is transferred between trophic levels, with the rest lost as heat. 3) Population sizes decrease at higher trophic levels due to inefficiencies in energy transfer between levels. Producers at the bottom have the largest populations since they directly absorb solar energy.

1. Energy Flow
Dr. K. Rama Rao
Department of Zoology

2. The existence of living beings such
as plants and animals depends on
the flow of energy in
them. Energy is needed for all the
biotic activities.
The most significant source
of energy for all ecosystems is the
sun.

3. Fig 1: Energy Flow

4. Energy flow is the amount
of energy that moves through a
food chain.
The largest source of energy for
an ecosystem is the sun.
Energy that is not used in
an ecosystem is eventually lost as
heat.

5. Energy and nutrients are passed
around through the food chain,
when one organism eats another
organism.
Fig 2: Energy food chain

6. The energy flow takes place via
food chain and food web. During
the process of energy flow in
the ecosystem.
Plants being the producers absorb
sunlight with the help of the
chloroplasts and a part of it is
transformed into chemical energy n
in the process of photosynthesis.

7. Fig 3: Energy flow in the ecosystem

8. The relative loss of energy due to
respiration is progressively
greater to higher trophic levels
because of proceeding of eating
criteria in ecology system.
Fig 4: Energy floe in trophic levels

9. The amount of energy at each
trophic level decreases as it moves
through an ecosystem.
As little as 10 percent of
the energy at any trophic level is
transferred to the next level; the
rest is lost largely through
metabolic processes as heat.

10. Fig 5: Energy flow at trophic levels

11. The interdependence of the flora
and fauna of an ecosystem is
evident from the fact that some
species met their energy (both
catabolic and anabolic) need by
consuming some other species.
Fig 6: Energy flow in animals

12. These herbivores are the primary
consumers, which are consumed by
the secondary consumers (the
carnivores).
Some bigger carnivores (the
tertiary consumers) live on the
smaller ones. This energy flow
pattern, from species to species

13. Fig 7: Energy flow pattern

14. In a simplified way, the sequential
dependence of a species of a higher
trophic level on another of a lower
trophic level for food is termed as
the “food chain” and food web”, as
many species take in, as food,
species of different trophic levels.

15. Fig 8: Species of different trophic levels

16. The efficiency of assimilation of energy
is higher at a lower trophic level and
lower at a higher trophic level.
Because of this, the population and the
total mass of a species of lower trophic
level are much larger than that of the
immediate higher trophic level.
The population structure is termed as
“population pyramid”

17. Fig 9: Population Energy pyramid