A group of species that includes an ancestral species and all its descendants.

The name given to each species, consisting of its genus and its species label

Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan

Kingdom composed of heterotrophs; many obtain energy and nutrients from dead organic matter

The scientific study of how living things are classified

Classification system in which each species is assigned a two-part scientific name

a key for the identification of organisms based on a series of choices between alternative characters

An approach to systematics in which organisms are placed into groups called clades based primarily on common descent.

Diagram that shows the evolutionary relationships among a group of organisms

trait that appears in recent parts of a lineage, but not in its older members

the principle that looks for the simplest, and probably most likely, scientific explanation that fits the evidence.

technique that uses the fossil record and rates of molecular change to deduce the time in geologic history when two species diverged