Final answer:
A gene pool contains different alleles for each heritable trait, with multiple alleles contributing to genetic diversity within a population. Population genetics explores these variations and their impact on genotypic and phenotypic expressions.
Step-by-step explanation:
A gene pool typically contains different alleles for each heritable trait. The gene pool consists of all the genes of all the members of a population. For each gene, this includes all the different alleles that exist in the population. Alleles are the different versions of a gene that code for the variations of a trait within a population. For example, the ABO blood type system in humans is determined by three alleles: IA, IB, and i.
Population genetics studies how selective forces impact the population through changes in allele and genotypic frequencies. This field of study analyzes the presence of multiple alleles within a population. Multiple alleles contribute to the diversity of traits expressed, and it is common that more than two alleles for a particular gene exist in the population, despite individuals only carrying two of those alleles.
The combination of alleles an individual inherits composes their genotype, which can be homozygous or heterozygous. The expression of the genotype results in the organism's phenotype, with expressions of dominant and recessive alleles affecting the observed traits.