O2 L4: Taxonomy and phylogeny

Taxonomy

Systematic ordering and naming of organisms

Phylogeny

The origin and diversification of any taxonomy, or the evolutionary history of its origin and diversification

Phylogenetic tree

Tree diagram showing hypothesized evolutionary history between different organisms

Homology

Character similarity due to common ancestry

Analogy

Non-homologous due to convergent evolutionary history between (NOT inherited from a common ancestor)

Cladistics

Approach/methodology for classifying organisms based on common evolutionary descent

Cladogram

Diagram used in cladistics to show evolutionary relationships between organisms

Clade

Unit of evolutionary common descent including ancestral lineage and all descendants

Phylogenetic tree

Branching diagram showing inferred evolutionary relationships among different biological species

Character

Organismal feature that varies between species

Ancestral character:

character state present in the common ancestor

Derived character

All other variant forms of the character that arises late within the group

Paraphyletic clade

Includes: Most recent common ancestor and some (not all descendants of that ancestor)

monophyletic clade

Includes: Most recent common ancestor and all descendants of that ancestor

Polyphyletic clade

group has at LEAST two separate evolutionary origins (does Not include most common recent ancestor of all members of a group)