define the following
systematics
taxon
phylogeny
homologous structures
vestigial structures
clade
Systematics: the study of the diversification of living organisms, including their classification and evolutionary relationships
Taxon: a group of organisms that are categorized together based on shared characteristics
Phylogeny: the evolutionary history and relationships among a group of organisms
Homologous structures: structures that are similar in different species because they have evolved from a common ancestor
Vestigial structures: structures in organisms that have lost some or all of their original function through evolution
Clade: a group of organisms that includes a common ancestor and all of its descendants