Homologous structures
The structures shared by a set of related species because they have been inherited, with or without modification, from their common ancestor. For example, the bones that support a bat's wing are similar to those of a human arm.
Homology
Similarity in DNA or protein sequences between individuals of the same species or among different species.
2. A character shared by a set of species and present in their common ancestor. Compare with analogy. (Some molecular biologists, when comparing two sequences, call the corresponding sites "homologous" if they have the same nucleotide, regardless of whether the similarity is evolutionarily shared from a common ancestor or convergent.

Homozygous
Having identical alleles for a particular trait. See also homozygote.
2. Having identical alleles in the corresponding loci of homologous chromosomes and therefore breeding true.

Homo erectus
A species of hominid that lived between 1.8 mya and 300,000 years ago; the first Homo species to migrate beyond Africa.

Homo Habilis
A species of hominid that lived between 1.9 and 1.8 mya, the first species in genus Homo, and the first hominid associated with clear evidence of tool manufacture and use.