BIOL 2122: Systematics, Phylogeny, & Classifications

Phylogeny

A classification of organisms that is comprised of nested, hierarchical categories intended to reflect evolutionary history.

Systematics

The study of biological diversity and evolutionary relationships, and the development of classifications.

Classification

The process of ordering and ranking organisms into groups and/or the product of this process.

Taxon (pl. taxa)

A group of animals at a particular categorical level (rank)

Why are species names in Latin?

• Clarity

• May be multiple common names for an organism

• May be different names in different languages

• To avoid confusion

Phylogenetic Trees/Dendrograms/Cladograms

Maps that represent patterns of relatedness among organisms, and can be used to develop classifications. The hypotheses of the way of life and constantly are undergoing revision.

Extant species

A living species

Monophyletic group; “Natural group”

Type of taxa that includes a most recent common ancestor and all its descendants; ideal goal of systematics

Paraphyletic group

A type of taxa that includes a most recent common ancestor and some descendants

Polyphyletic group

Includes species that arose from two or more ancestors