3. Definition :
The term ecosystem was proposed in 1935 by a British
Botanist Professor Arthur Tansley.
Ecosystem is defined as, “the basic functional unit of
ecology and consists of interacting organisms and all
aspects of environment in any area.
"Ecosystem" means a dynamic complex of plant, animal
and micro-organism communities and their non-living
environment interacting as a functional unit".
5. Biotic Components :
Plants are called as
producers.
Animals on the other
hand consume products
of plants and animals.
They are therefore
called as consumers.
6. Microbes which include bacteria, fungi and insects break
down the dead matter, consume some of the decomposed
products and release simple substances which are used by
the plants to manufacture their food. They are therefore
called as decomposers.
7. Abiotic Components :
These are
comprised of
physical and
chemical substances
which include
sunlight, water,
oxygen, carbon-
dioxide, minerals,
dead plants and
animal matter and
other factors such
as temperature,
light, heat, wind,
rainfall etc.
8. Classification :
ABIOTIC COMPONENTS BIOTIC COMPONENTS
Sunlight Primary producers
Temperature Herbivores
Precipitation Carnivores
Water or moisture Omnivores
Soil or water chemistry
(e.g., P, NH4+)
Detrivores
10. There are many different food chains in the
ecosystems (biosphere), these chains are
interconnected to form a network of food
chains which is called food web.
11. Principles of Ecosystem :
Energy thing is related
to every thing else.
Everything must go
some where
Nature knows best
In order to preserve
the nature anything
which is removed form
the nature by human
efforts must be
replaced and anything
which is added to it
must be removed.
22. Transformation of energy :
• The transformations of energy in an ecosystem
begin first with the input of energy from the
sun. Energy from the sun is captured by the
process of photosynthesis.
• Carbon dioxide is combined with hydrogen
(derived from the splitting of water molecules) to
produce carbohydrates (CHO). Energy is stored
in the high energy bonds of adenosine
triphosphate, or ATP .
26. Controls on Ecosystem Function :
There are two dominant
theories of the control
of ecosystems.
The first, called bottom-
up control
The second theory,
called top-down control
