Question

Explain the significance of natural selection by giving an example.

Answer 1

Hint:The theory of natural selection was given by Darwin through his book On the origin of species in 1859. It states that the organisms change with time due to the changes in physical and behavioural traits which are inherited over generations.

Complete answer:
To answer this question, we must know about the importance of the theory of natural selection.
-The three principles behind the theory of natural selection are:-
-The characteristics in an organism are inherited over generations.
-The number of offspring produced is greater than those that survive.
-The offsprings with favourable characteristics survive and have more offsprings as compared to ones with less favourable traits.
-The conditions required for natural selection to take place are heredity, fitness of an organism, variation among the members and reproduction.
Significance of natural selection:
-The variations occur in the genotype which is inheritable. It increases the chance of survival.
-It leads to the evolution of new species.
-It multiplies the beneficial mutations over generations and eliminates the harmful ones.
-The organisms are better adapted to physiological and biological condition.
Example of natural selection are- In a habitat where there are red worms and green worms. The birds like to eat the red worms. This will increase the population of green worms and few red worms will be seen. After successive generations, the green worm will be found and eventually no red worms would be seen.
Note:Mutation is the root cause of evolution. Mutation is the change in DNA sequence. It can occur due to environmental factors like radiation, stress, diseases or due to internal factors like DNA copying, or mistakes during cell division.