Cladistics and Phylogeny Vocabulary

Flashcards covering key vocabulary related to cladistics and phylogenetic analysis.

Cladistics

A method of classifying organisms based on common ancestry, focusing on branching patterns.

Clade

A group of organisms that includes an ancestor and all its descendants.

Node

A point in a cladogram where a single lineage splits into two or more lineages.

Derived Character

A trait present in an organism but absent in its last common ancestor.

Morphological

Relating to the physical traits or structures of organisms.

Apomorphy

A derived trait that is unique to a specific group of species.

Plesiomorphy

An ancestral trait that is retained throughout evolution.

Autapomorphy

A derived trait that is unique to a single taxon.

Synapomorphy

A derived trait of a recent ancestor wasn’t passed on to any descendants.

Homoplasy

A shared character state that is not inherited from a common ancestor.

Taxon

A species

Symplesiomorphy

A trait that is the same across all generations.

Cladogram

A diagram that shows the relationships among different groups based on shared characteristics.

Outgroup

A group that is distant from the other groups being studied.

Phylogenetic Tree

A diagram that represents evolutionary relationships among multiple species; it is a hypothesis that may change over time.

Monophyletic

A group that includes an ancestor and all of its descendants.

Paraphyletic

A group that includes an ancestor but not all of its descendants.

Polyphyletic

A group that does not include the most recent common ancestor of all its members.

Homologous

Structures that are similar in form due to shared ancestry, though they may perform different functions.

Analogous

Structures that have similar functions due to convergent evolution but have different structural origins.