Final answer:
The term the question refers to is the 'gene pool,' which contains all alleles at every locus in all members of a population. Allele frequencies describe how common an allele is within the gene pool. Population genetics studies the changes in these frequencies due to various evolutionary factors.
Step-by-step explanation:
Gene Pool and Allele Frequency
In biology, the concept described is known as the gene pool. The gene pool includes all copies of every type of allele at every locus in all members of a population. When only one allele for a gene exists in a population, and therefore all individuals are homozygous for that allele, the allele is said to be fixed. However, when there are multiple alleles for a gene, individuals can be either homozygous, having two identical alleles; or heterozygous, having two different alleles.
To understand allele frequencies, imagine a population with 100 members, and each member has two copies of a gene, totaling 200 gene copies in the gene pool. If a gene has two forms, or alleles, named A and a, then the allele frequency can be determined by counting how many As and how many as are present in the gene pool.
Population genetics is the study of how allele and genotypic frequencies change over time within a population. It considers factors such as mutation, selection, and genetic drift that influence these frequencies.