Food Web: A Network of Food Chains

“It is a network of food chains which become inter-connected at various trophic levels so as to form a number of feeding connections amongst the different organisms of a biotic community.”

Food Web is meant for increasing the stability of an ecosystem by providing alternate source of food and allowing the endangered population to grow in size. Normally a food web operates according to taste and food preferences of the organisms at each trophic level. 

However, availability of food source and other compulsions are equally important.

Example-> In Sunderbans, the tigers eats fish and crab in the absence of their natural preys.

Some organisms normally operate at more than on trophic level. Thus Human beings are not only herbivores but also carnivores at various levels. Jackals are both carnivores and scavengers. Snake feed on mice (herbivores) as well as frogs (carnivores). 

Therefore, the concept of Food Web appears more real ecologically than the concept of a simple Food Chain.

Food Chain

   

“The transfer of food energy from the producers, through a series of organisms (herbivores to carnivores to decomposers) with repeated eating & being eaten, is known as Food Chain.” It includes:-

1) Primary Consumers or Herbivores:  They are animals which feed on plants or plant products.

Eg. grasshoppers and several other insects, rabbit. Hare, deer, antelope, elephant, zooplankton etc.

Herbivores are also called key industry animals because they convert plant matter in to animal matter.

2) Secondary Consumers or primary Carnivores: They ingest or prey upon herbivores animals.

Eg. Frog, predator, Insects, several Birds, Fishes, Wild Cat, Fox, Jackal (also Scavenger) etc.

3) Tertiary Consumers or Secondary Carnivores: They are larger carnivores which prey upon primary carnivores.

Eg. Wolf (feeds on fox), Snake (Prey upon frog).

4) Top Carnivores: They are the last order consumers or carnivores which are not preyed upon by other animals because of their size, agility & ferociousness,

Eg. Shark, Crocodile, Eagle, Peacock, Tiger, Lion.

Some common food chains are:-

**Land:

a) Grass-->Grass Hoppers-->Frog-Snakes-->Peacock/Falcon

b) Vegetation-->Rabbit-->Fox-->Wolf-->Tiger

**Aquatic:

a) Phytoplankton-->Zooplankton-->Small Crustaceans-->Predator Insects-->         Small Fish-->Larger Fish-->Crocodile

In Nature we distinguish two general types of Food Chains:

1) Grazing Food Chain: - This type of food chain starts from the living green plants goes to grazing herbivores & on to carnivores. It is directly dependent on influx of solar radiation.

2) Detritus Food Chain: - This type of food chain goes from dead organic matter to microorganisms & then to organisms feeding on detritus & their predators. Such ecosystems are less dependent on direct solar energy.

Ecology-“The Study of Structure & Function of Nature”

“Ecology word is combination of two Greek words “Oikos (home, house or dwelling place) & Logos (the study of).” This describes relation of organisms & their surroundings (environment).

When we go much deeper in understandings of Nature, broadly, we find two important aspects i.e. organisms and its surroundings (environment). Which, mutually co-related and dependent on each other with much complex relation.

Time to time many scientist used and coined different terminologies to study Nature.

French zoologist Isodore Geoffroy st.Hilaire in 1859 had coined the term “Ethology” for “Study of the relations of the organisms within the family & society in the aggregate & in community.”

Charles Darwin in his book “On the Origin of Species” (1859) has used several potential terms, which can be used in explanation of Modern Ecology in broader way.

In 1886 Haeckel used the term Ecology as “the knowledge of the sum of the relations of organisms to the surroundings outer world to organic & inorganic condition of existence.”

R Mishra (1967) described Ecology as “Interactions of form, functions & factors.” These three factors combinedely construct the triangle of Nature.

Odum in 1969 define Ecology as “the study of structure & function of Nature.

Krebs (1985) has defined Ecology as “Ecology is the scientific study of the interactions that determine the distribution & abundance of organisms.”

In more recent updates, the terminology “Biotic (Living) & Abiotic (non-living) used in describing the Ecology as its component and both are related with each other & functions accordingly as a proper system.