Question

Explain the significance of variation.

Answer 1

Genetic variation is an important force in evolution as it allows natural selection to increase or decrease the frequency of alleles already in the population.

This variation permits flexibility and survival of a population in the face of changing environmental circumstances. The presence of diseases and parasites maintains variation in a species, particularly those associated with blood groups. The first response of a species confronted with environmental changes, such as climate change, is to shift its range. So a species could move poleward, or to higher altitudes. When that does not work variations help individuals survive in harsh conditions, and adapt to the changes. The variations that help resist parasites persist in a population. Most of the parasites are vulnerable to a particular parasite, but there is a small number resistant to it. These individuals have an advantage and increase in numbers until they are enough to keep the parasite from spreading. This will allow vulnerable individuals to avoid infection and survive. When the parasite adapts to the resistant strain, they often lose the ability to infect some other strain. So, these are the significance of variation.