Final answer:
In a single species, homologous genes are called alleles, which form different versions of a gene situated on homologous chromosomes. These alleles are responsible for the variation of traits within a species.
Step-by-step explanation:
In a single species, homologous genes are called alleles and collectively make a gene family. Alleles are different versions of genes that are located on the homologous chromosomes, which have the same size, shape, and contain the same genes.
Each of the matched pairs of chromosomes in a diploid organism is called a homologous chromosome. For example, human cells have 23 pairs of homologous chromosomes, with each chromosome derived from a different parent, which allows for variation within the species based on the different combinations of alleles inherited.
Traits, which are variations of characteristics, are determined by the specific alleles that an organism inherits from its parents. For instance, blood type in humans is determined by which two versions of the allele on the homologous chromosomes are inherited, giving rise to variations such as AA, BB, AB, or OO combinations within individuals of a species.