Phylogeny and Systematics

Flashcards covering key vocabulary from the lecture on phylogeny and systematics.

Phylogeny

The evolutionary history and relationships among a group of organisms.

Systematics

The classification of organisms and determining their evolutionary relationships.

Taxonomy

The science of naming and classifying species.

Phylogenetics

The study of evolutionary history using phylogenetic trees.

Phylogenetic tree

A diagram that represents the evolutionary history of a group of organisms, showing the amount of change over time.

Cladogram

A diagram that shows the relationships among species, using branching lines to represent lineages.

Node

A branching point in a cladogram that represents a common ancestor.

Clade

A group of species including a common ancestor and all its descendants.

Sister taxa

Two clades that emerge from the same node in a phylogenetic tree.

Basal taxon

A lineage that evolves from the root and remains unbranched.

Synapomorphy

A derived character shared by members of a clade.

Ancestral characteristic

A trait that arose before the most recent common ancestor of a group.

Outgroup

A lineage that is the least closely related to the rest of the organisms in a study.

Monophyletic group

A group that includes the most recent common ancestor and all of its descendants.

Paraphyletic group

A group that includes the most recent common ancestor but not all its descendants.

Polyphyletic group

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

Principle of parsimony

A methodological principle that suggests the simplest explanation, requiring the fewest assumptions, is preferred.