Why is variation beneficial to the species but not necessarily for the individual?

Explanation

Variations are beneficial to the species than individual because sometimes for a species, the environmental conditions change so drastically that their survival becomes difficult. For example, if the temperature of water increases suddenly, then most ofthe bacteria living in that water would die. Only few variants that are resistant to heat would be able to suvive. However, if there variants were not there, then the entire species ofbacteria would have been destroyed. Thus, these variants help in the survival of the species. However, all variations are not necessarily beneficial for the individual organisms.