BIO 156 Phylogenies and Systematics

Flashcards covering key terminology and concepts related to phylogenies, systematics, and evolutionary relationships.

Systematics

The study of evolutionary relationships among organisms.

Phylogeny

A hypothesis about the relationships among taxa that describes evolutionary history.

Cladistics

A method of inferring evolutionary relationships based on shared derived characteristics.

Synapomorphy

A shared derived characteristic that defines a clade.

Taxonomy

The science of classifying and naming living things.

Character matrix

A table showing taxa and their characteristics used to build cladograms.

Out-group

A group closely related to, but not a member of, the group under study, useful for polarizing phylogeny.

Parsimony

The principle that prefers the phylogeny requiring the least amount of evolutionary changes.

Homology

Shared characteristics due to common ancestry.

Homoplasy

Independent evolution of shared characteristics, not due to common ancestry.

Convergent Evolution

Independent evolution of shared traits due to similar environmental pressures.

Monophyletic clade

A clade that includes a common ancestor and all of its descendants.

Paraphyletic group

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

Polyphyletic group

A group that does not include the common ancestor, sharing traits but not a common lineage.

Phylogenies 

The evolutionary history of a group of organisms, represented in a branching diagram called a phylogenetic tree; through a common ancestor.