Lecture 2 - The tree of life

Definition of evolution

A change in allele frequency in a gene pool

What evidence can be used to examine lineages

• Behavioural and ecological

• Molecular

• Morphological

What is homology

Any similarity between traits because of shared ancestry

What is apomorphy

Derived characteristics because of homology

What is synapomorphy

A shared derived character - an apomorphy shared by two or more taxa that is thought to have evolved in their most recent common ancestor

What is a node

Branch point that represents a common ancestor

Define cladistics

Classification where organisms are grouped by their most recent common ancestry. Evidence is typically from examining synapomorphies

Define monophyly

a term used in cladistics for a group that includes an ancestor and all of its descendants, forming a single evolutionary lineage

Define autapomorphy

A derived trait that is unique to a given taxon, do not provide useful grouping information