Variation during reproduction is beneficial to the species but not necessarily for the individual?
The Attempt at a Solution
I only know about variation during reproduction is beneficial to the species but I don't know anything about how it is not necessarily beneficial for individual.
I think it is beneficial for species because it helps the species of various organisms to survive and flourish even in adverse environment. For example if there is a population of certain bacteria living in temperate water (which is neither very hot no very cold) and the temperature of water increases too much due to global warming then most of these bacteria will not be able to tolerate excessive heat and hence die but some bacteria which had variations to resist heat would survive and grow further.
But,I do not know how it is not necessarily beneficial for individual?
Note:I am a high school student and English is my second language. Thanks!