Bio 181-Phylogeny

Taxonomy

Naming and classifying organisms

Phylogeny

The evolutionary history and relationship of organisms

Taxon

A group of organisms at any classification level

Clade

A common ancestor and ALL its descendants

Cladogram

A diagram showing evolutionary relationships

Node

A branching point representing a common ancestor

Sister groups

Groups that share their most recent common ancestor

8 classification levels

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Bionomial nomenclature

A two-part scientific name: Genus and species

Scientific species name

Genus capitalized, species lowercase, both italicized

Homologous traits

Similar traits inherited from a common ancestor

Homoplasy

Similar traits that evolved later

Ancestral trait

An older trait inherited from ancestors

Derived trait

A newer trait that evolved later

Convergent evolution

Unrelated organisms independently develop similar traits

Outgroup

An organism outside the main group being studied

Ingroup

The main group of organisms being studied

Root of a phylogenetic tree

The starting point representing the common ancestor of the tree

Monophyletic group

A common ancestor and all its descendants

Paraphyletic group

A common ancestor and some, but not all, descendants

Polyphyletic group

A group that excludes the most recent common ancestor

Principle of parsimony

Prefer the explanation requiring the fewest evolutionary changes

Phylogenetic trees

Evolutionary relationships and patterns of descent

Nerby branches

Do not mean one species evolved directly from the other

Synapomorphy

A shared derived trait used to identify related groups