why varaition is not necessary for individual but essential for the species?
what is a food chain and food web?

Asked by my3shyll | 21st Mar, 2017, 07:32: AM

Expert Answer:

Variations are beneficial for the survival of species. Populations of organisms fill well-defined places or niches in the ecosystem, using their ability to reproduce. However, niches can change because of reasons beyond the control of the organisms and could even wipe out the entire population. However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive. 
For example- If there were a population of bacteria living in temperate waters and suppose the water temperature were to be increased by global warming, most of these bacteria would die, But the few heat resistant variants would survive and grow further. Variation is thus useful for the survival of species over time.

The food chain is a series of organisms linked by their feeding relationships, through which food energy is passed in an ecosystem. A sequence of organisms is formed here, each of which uses the next, lower member of the sequence as a food source.

For e.g. a plant is eaten by a small fish, which is eaten by a larger fish, which is eaten by a bird, and so on.

Food web is a complex network of feeding interrelations among species in a natural ecosystem by which energy and nutrients are passed on from one species of living organisms to another.

Answered by Sivanand Patnaik | 21st Mar, 2017, 08:04: AM