Structural components of ecosystem?
1. Abiotic Component
These include the non-living, physico - chemical factors such as
air, water, soil and the basic elements and compounds of the
Abiotic factors are broadly classified under three
Climatic factors which include the climatic regime and physical
factors of the environment like light, humidity, atmospheric
temperature, wind, etc.
Edaphic factors which are related to the structure and
composition of soil including its physical and chemical properties,
like soil and its types, soil profile, minerals, organic matter,
soil water, soil organisms.
Inorganic substances like water, carbon, sulphur, nitrogen,
phosphorus and so on. Organic substances like proteins, lipids,
carbohydrates, humic substances etc
2. Biotic Component
It comprises the living part of the environment, which includes
the association of a number of interrelated populations belonging
to different species in a common environment.
The populations are that of animal community, plant community
and microbial community.
Biotic community is distinguished into autotrophs, heterotrophs
Autotrophs (Gr: auto - self, trophos - feeder) are also called
producers, convertors or transducers.
These are photosynthetic plants, generally chlorophyll bearing,
which synthesize high-energy complex organic compounds (food) from
inorganic raw materials with the help of sunlight, and the process
is referred as photosynthesis.
Autortophs form the basis of any biotic system.
In terrestrial ecosystems, the autotrophs are mainly the rooted
In aquatic ecosystems, floating plants called phytoplankton and
shallow water rooted plants called macrophytes are the dominant
Heterotrophs (Gr: heteros - other; trophs - feeder) are called
consumers, which are generally animals feeding on other
Consumer's also referred as phagotrophs (phago - to ingest or
swallow) or macroconsumers are mainly herbivores and
Herbivores are referred as First order consumers or primary
consumers, as they feed directly on plants.
For e.g., Terrestrial ecosystem consumers like cattle, deer,
rabbit, grass hopper, etc.
Aquatic ecosystem consumers like protozoans, crustaceans,
Carnivores are animals, which feed or prey upon other
Primary carnivores or Second order consumers include the animals
which feed on the herbivorous animals.
For e.g., fox, frog, predatory birds, smaller fishes, snakes,
Secondary carnivores or Third order consumers include the
animals, which feed on the primary carnivores.
For e.g., wolf, peacock, owl, etc.
Secondary carnivores are preyed upon by some larger
Tertiary carnivores or Quaternary consumers include the animals,
which feed on the secondary carnivores.
For e.g., lion, tiger, etc.
These are not eaten by any other animals.
The larger carnivores, which cannot be preyed upon further are
called top carnivores.
Saprotrophs (Gr: sapros - rotten; trophos - feeder) are also
called decomposers or reducers. They break down the complex organic
compounds of dead matter (of plants and animals).
Decomposers do not ingest their food. Instead they secrete
digestive enzymes into the dead and decaying plant and animal
remains to digest the organic material. Enzymes act upon the
complex organic compounds of the dead matter.
Decomposers absorb a part of the decomposition products for
their own nourishment. The remaining substances are added as
minerals to the substratum (mineralisation).
Released minerals are reused (utilised) as nutrients by the