Phylogenetics Vocabulary

Flashcards covering key vocabulary and concepts from a Phylogenetics lecture.

Phylogeny

Genealogical relationships among organisms from a common ancestor; the foundation for understanding evolutionary biology.

Phylogenetics

Study of evolutionary relationships among species.

Systematics

The study of classifying, naming, and determining evolutionary relationships of organisms; includes phylogenetics and taxonomy.

Taxonomy

Classification and naming of organisms.

Binomial nomenclature

Systematic naming system of species developed by Carl Linnaeus.

Taxon (Taxa)

A grouping of organisms within a hierarchical classification system.

Adjacent branches

Represents more closely related taxa in a phylogenetic tree.

Characters

Degree of divergence based on characters; examples include morphology, cell structure, biochemistry, behavior, and genetic characters.

Cladistics

The science of quantifying divergence based on shared, derived character states.

Plesiomorphies (or homologies)

Ancestral characters inherited without change from a common ancestor.

Synapomorphies

Shared, derived characters.

Homoplasy

Derived traits that are the result of convergent evolution or character reversal, but not derived from a common ancestor.

Clade

Monophyletic grouping of ‘branches’ in a phylogeny.

Monophyletic clade (monophyly)

A set of taxa derived from one common ancestor and includes all descendants in group name.

Paraphyletic taxon (paraphyly)

Group of taxa derived from one common ancestor but does not include all descendants from that common ancestor in group name.

Ingroup

The taxa in which you are interested in determining their evolutionary histories.

Outgroup

A taxon closely related to the monophyletic group of taxa whose relationships are under examination (the ingroup).

Node

The branching point in a phylogeny that represents an ancestral taxon.

Parsimony

Simplest explanation requiring the fewest number of assumptions should be preferred.