Introduction to Phylogenetics

These flashcards cover key vocabulary and concepts related to phylogenetics, including definitions of important terms and principles associated with the evolutionary relationships among species.

Phylogenetic Tree

A diagram that shows the evolutionary relationships between species or groups based on common ancestry.

Node

A point where two lineages split, representing a common ancestor.

Branch

A line showing the passage of genetic change over time.

Tip (Leaf)

The end of a branch representing a living or extinct species.

Root

The common ancestor of all species in the tree.

Clade

A group that includes an ancestor and all its descendants, also called a monophyletic group.

Sister Taxa

Two species or groups that share an immediate common ancestor.

Outgroup

A species or group outside the group of interest, used for comparison.

Descent with Modification

The core principle of evolution indicating all species come from common ancestors and that changes occur in traits over time.

Derived Trait

A new version of a trait that evolved in a descendant, as opposed to an ancestral trait.

Homologous Characters

Features shared by two or more species because they were inherited from a common ancestor.

Synapomorphy

A shared derived character that is found in two or more taxa and inherited from their most recent common ancestor.

Plesiomorphy

An ancestral character state that was present in the common ancestor of a group.

Morphological Phylogeny

The reconstruction of evolutionary relationships using physical traits.

Homoplasy

Trait similarity that is not due to shared ancestry but may arise from convergent evolution or other factors.