Define food chain and food web?

Answer 1

Food ChainA simple chain of feeding relationship between three or four organisms is called a food chain. Food WebA food web is a diagram, of some sort, that links at least two food chains together. Food webs describe how energy is passed throughout a section of an ecosystem (or an entire ecosystem).

An example of a food web:

[ Grass ] -> [ Zebra ] -v

[ Leaf ] -> [ Giraffe ] - [ Lion ]
The transfer of food energy from the source in plants through a series of organisms with repeated eating and being eaten is the Food Chain. The interlocking pattern of Food Chains makes up the Food Web.
A food chain traces the movement of energy flow from one organism to the next. A chain usually starts with an autotroph that converts energy from the sun into chemical energy (glucose). The passing of energy occurs when a heterotroph (organisms that collect chemical energy that is created by other organisms) consumes an autotroph. A food chain doesn't accurately show all the kinds of organisms that each heterotroph can consume to get energy from, so scientists invented food webs to display the various pathways that energy movement can happen in an ecosystem.