| A | B |
|---|
| Biodiversity | Variety of living organisms and the variety of ecosystems they form |
| Systematics | Scientific study of the diversity of organisms and their evolutionary relationships |
| Taxonomy | Science of naming, describing, and classifying organisms |
| Classification | Arranging organisms into groups based on their similarities |
| Binomial system of nomenclature | Linnaeus, each species is assigned a unique two-part name |
| Genus | First part of a scientific name |
| Specific epithet | Second part of a scientific name |
| Taxon | Formal grouping of organisms at any given level |
| Lateral gene transfer | Movement of genes from organisms in one taxon to related organisms in another taxon |
| Phylogeny | Evolutionary history of a group of organisms from a common ancestor |
| Homology | The presence, in two or more species, of a structure derived from a recent common ancestor |
| Homoplasy | A characteristic that superficially appears homologous, but is actually independently acquired |
| Shared ancestral characters | Features that were present in an ancestral species and remain present in all groups descended from that ancestor |
| Shared derived characters | Traits found in two or more taxa that first appeared in their most recent common ancestor |
| Molecular systematics | Focuses on the use of molecular structure to clarify evolutionary relationships |
| Monophyletic taxon | Includes an ancestral species and all its descendants |
| Paraphyletic taxon | Group that contains a common ancestor and some of its descendants |
| Polyphyletic group | Consists of several evolutionary lines that do not share the same recent common ancestor |
| Phenetics | An early approach to the quantitative analysis of characters |
| Cladograms | Branching diagrams that express the evolutionary relationships of organisms |
| Node | Each branch point that represents the immediate common ancestor of the next monophyletic group depicted in the cladogram |
| Parsimony | Simplest explanation to interpret data |
| Outgroup analysis | Method for estimating which attributes are shared derived characters in a given group of taxa |
| Outgroup | Taxon that is considered to have diverged earlier than the taxa under investigation |
