Question

How can a rare variation in a population become a common characteristic in a population? Explain with examples.

Answer 1

Variation may be defined as Differences among individuals of a species.
variation arises due to genetic factors and environmental influence.
Rare variation can become a common characteristics in a population.
example :
consider a group of 12 red beetles which live in bushes with green leaves.
Their population will grow by sexual reproduction and hence can show variations.
And a crow which visits this place, eats red beetles.
situation 1: crow eat more red beetles and few red beetles wil be left out .
One green beetle will grow due to colour  variation during reproduction  and this colour will be passed to offspring.
Situation 2:
crow cannot eat green beetles as they cannot see them in green bushes due to blending with the environment , but it continues to eat only red beetles.
Thus a rare variation can become a common characteristics in a population.