Biotic Factors in Ecosystem

Dr. Richa Singh
Principal
V.I.E.T. G.B. Nagar

Biotic factors are the living parts of an ecosystem. Biotic factors such as soil bacteria, plant life, top predators and polluters can all profoundly shape which organism can live in an ecosystem Biotic factors along with non living abiotic factors such as temperature, sunlight, Geography, chemistry determine how ecosystem looks like and what ecological niches are available.
Biotic factors are grouped into three major groups which define their role in the flow of energy by which all living things in the ecosystem need to survive. These groups are –
(1) Decomposers- Decomposers or detritivores are organisms that use organic compound from producers and consumers as their source of energy. They are important to ecosystems because they breakdown materials from other living things into simpler forms which can be used again by other organisms.
Decomposers include soil bacteria, fungi, worms, flies and other organisms that breakdown dead materials or waste products from other life forms. They are distinct from consumers, because consumers usually consume other organisms while they are still alive.
Decomposers on the other hand, metabolize waste products that might not be of interest to consumers such as rotting fruit and dead animals.
In the process they break down these dead things into simpler chemicals that can be used by hetrotrophs to thrive and produce more energy for the ecosystem as a whole.
The principle behind the practice of composting – where waste scraps of plants and animals products are put into a pile, where decomposers such as bacteria, worms and flies are allowed to thrive. These decomposers turn the waste products into rich fertilizers for the composer’s garden which then grow bigger and healthier.
Decomposers are the link between the bottom of an ecosystem’s energy pyramid and the other levels. Decomposers can take energy and raw materials from the dead plants herbivores, lesser carnivores and even top carnivores and break it down into a form that can be used by the ecosystems, producers to make it easier for them to harness sunlight. In this way ecosystemic energy cycle is preserved.

(2) Producers – They are known an autotrophs, from the Greek words ‘auto’ means ‘self’ and ‘troph’ means ‘food’ It means organisms that make their own food by using organic materials and energy sources. Producers are extermely important, without them no life could exist at all.
when the first life forms appeared on the earth there were no other life form to feed her. The first life form had to be producers, producers remain vital today as the life forms that can harness inorganic energy to be used as fuel for life. There are two major classes of producers.
(a) Phatoautotrophs – They are the most common type of producers on the earth. These producers harness energy from sunlight to power their life functions, Green plants, Green algae and some bacteria. Most photoautotrops use pigment such as chlorophyll to catch photons from the sun and harvest their energy. They then package that energy into a form that all Life forms can use, and create protiens, sugars, lipids and more essential materials for life.
In most ecosystems producers (plants) are multi- cellular, highly complex and very efficient at turning sun light into fuel for living organisms from the bottom of the energy pyramid. All other organisms depend upon the energy plants harvest from the sun to survive.

(b) Chemoautotrophs – These are fairly rare in most ecosystems. They obtain energy from chemicals e.g., hydrogen, Iron and sulfur which are uncommon in most environments. Due to their unusual biochemistry they still play an important role.
Some methanogens i.e., micro organisms that make methane are chemoautotrophs. Methane a green house gas is more powerful than CO2, in regulating the plants temperature. Other chemoautotrophs can produce similarly powerful chemical with their unique metabolism.
Though it is not known that the first form of life on Earth were photoautotrophs or chemoautotrophs Photoautotrophs are more common today, but that may simply be because sunlight is more plentiful than the chemicals which chemoautotrophs use as their energy source.
(3) Consumers – These are called heterotrophs. These organisms eat other living organisms in order to obtain energy. In Greek term ‘hetero’ means other and ‘trophs’ means food.
Herbivores eat plants, carnivores eat animal and omnivores eat plants as well as animals, these all are heterotrophs.
Heterotrophy probably evolved when some organism discovered that they could eat autotrophs as a source of energy, instead of creating their own energy and organic material. Some autotrophs subsequently evolved symbiotic relationsships with consumers, such as angiosperms- plants which produce neetars and fruits to attract animals who ultimately help them to reproduce.
Most Levels of most ecosystem, energy pyramids consist of consumers, herbivores, minor predators and top predators who eat other organisms.