AP BIOLOGY

Detailed explanation-1: -When a phenotype produced by certain alleles helps organisms survive and reproduce better than their peers, natural selection can increase the frequency of the helpful alleles from one generation to the next – that is, it can cause microevolution.

Detailed explanation-2: -Natural selection acts on the phenotype (the traits or characteristics) of an individual. On the other hand, natural selection does not act on the underlying genotype (the genetic makeup) of an individual. For many traits, the homozygous genotype, AA, for example, has the same phenotype as the heterozygous Aa genotype.

Detailed explanation-3: -Natural selection acts on the whole organism; the unit of selection is the individual. NS cannot act on individual alleles (genes). Natural selection acts on the phenotype, not the genotype. But it can cause changes in the genotype.

Detailed explanation-4: -Natural selection act on genotype or phenotype? NATURAL SELECTION acts on an organism’s characteristics (phenotype), not directly on its alleles (genotype). Natural selection favors a particular physical trait or behavioral characteristic over another.