Bio 204 Final

Phylogeny

The branching evolutionary history of a group of organisms

Phylogenetic Tree

A simplified diagram of the history. Represents the patterns of ancestry between ancestors and their descendents

Systemics

piecing together the tree of life

Phylogenetic trees Help with

Taxonomy, diseases and conservation

Branch (Phylogenetic trees structure)

Population over time

Node (Phylogenetic trees structure)

a point in time when an ancestral group split into two or more descendant groups. Represents the most recent common ancestor of the descendant groups

Root (Phylogenetic trees structure)

the most ancestral branch of the tree

Outgroup (Phylogenetic trees structure)

A taxon closely related to a particular monophyletic group

Monophyletic Group (Clades)

An ancestral population and all of its descendent lineage

Non-Monophyletic Group

A set of organisms that does not all the descendents of their most recent common ancestors

Synapomorphy

A shared, derived trait. They include the origin of novel characteristics

Polytomy

a node depicting three or more descendents branches

Sister Taxa

closely related taxa on adjacent branches arising from the same node

Homology

traits that are similar due to shared ancestry

Homoplasy

traits are similar for reasons not related to common ancestory

Paraphyletic Group

the ancestral population and some of its descendents

Polyphyletic Group

a group whose members lasts common ancestor is not a member of the group

Parsimony

the idea that most likely explanation for a phenomenon is the simplest

Adaptive Radiation

when a single lineage rapidly produces many descendents species with a wide range of adpative forms

Signs of a adaptive radiation

• Rapid Lineage multiplication from a single common ancestor

• Rapid speciation and ecologically-linked phenotypic diversification

• Density-dependent slowdown in diversification rates as ecological niches are filled

What triggers adaptive radiation

• Extrinsic Factors (favorable new conditions in the environment)

Intrinsic Factors (the evolution of key morphological, physiological, or behavioral traits)