Final answer:
The term 'allelic' variation refers to differences in specific genes, with alleles being alternative versions of a gene. Allelic variation is a key factor in genetic diversity and is observed in population genetics, with examples like the ABO blood type system in humans.
Step-by-step explanation:
The term allelic variation refers to differences in specific genes. Allelic variation occurs when there are different versions, or alleles, of a gene present in a population. These alleles are alternative forms of a gene that determine particular traits for a characteristic. An example of this can be seen in the ABO blood type system in humans, where three alleles are responsible for the different blood types, and every individual carries two of these alleles.
Mendelian genetics and population genetics both observe how alleles are transmitted through generations and how they alter population dynamics. The presence of multiple alleles contributes to the genetic diversity within a population, leading to phenomena such as continuous variation and the resulting range of traits observable in individuals. Population variation, which includes allelic variation, is an essential aspect of evolutionary biology, as it is the raw material on which natural selection acts.