Food Chain

The food chain is the energy stored by plants is passed along through the ecosystem in a series of steps eating.

The food chain is described as Food and feeding relationship among organisms in an ecosystem.

Ex - Grass   Grasshopper   Toad   Snake  

The grass is eaten by Grasshopper, Then the grasshopper is eaten by the toad and the toad becomes food for Snake.

Food chains usually contain only three or four steps. Different food chains are found in nature. There are two major types of food chains,

  1. Grazing food chain.
  2. Detrital food chain.
These food chains are distinguished by their source of energy or food for the initial consumers.
The most obvious food chain is the grazing food chain.

Grazing Food Chain

This food chain begins with green plants, cattle grazing on grassland, birds feeding on fruit, insects feeding on plants, zooplankton feeding on phytoplankton.
The consumer directly feeding on stored food of plants. They are referred to as primary consumers or herbivores.
Organisms that feed on the primary consumer are the secondary consumers or the carnivores.
Ex- 
  • Birds
  • Snakes
  • Lizards
  • Leopards etc...
(   Grass →  Grasshopper →  Toad  → Snake  )

Detritus food chain

The primary source of energy in dead and decaying organic matter(animals and plants remain) is known as detritus. Primary consumers are 'detritivores' which feed upon the detritus.
There are two groups of detritivores,
  1. Microscopic forms.
  2. Macroscopic forms.
The macroscopic organisms fragment the dead matter into smaller particles on which the microscopic forms can act.

Microscopic decomposers - 
  • Bacteria
  • Fungi
Macroscopic decomposers
  • Mites
  • Millipedes
  • Nematodes
  • Slugs
  • Molluscs
  • Mayflies
  • Stoneflies
  • Caddisfly
Bacteria and Fungi obtain their nourishment from detritus by secreting digestive enzymes onto dead organic matter. That causes the breakdown of the dead material into simpler substances.
Then nutrients are returned back to the soil and water and are reused by producers for the synthesis of organic food.

The grazing food chain is divided into two major factors.
  1. Predatory food chain.
  2. Parasitic food chain.
Animal parasites are named carnivores.
Plants parasites are named herbivores.

Ex - Grass  Cow  Flea  Leptomonas

In a predatory food chain that moves from producer to last consumer level, the last individual at each higher level becomes less.
In a parasitic food chain from the producer the individuals at each level increase in number.

Grazing food chains play a major role in energy flow in deep-water aquatic ecosystems.
Detrital food chains dominate play a major role in terrestrial and shallow-water ecosystems.