Phylogenetic Tree

Phylogenetic Tree

A graphical summary showing the hypothesized evolutionary history of living organisms.

Is a Phylogenetic Tree Fact or a Hypothesis?

Hypothesis

Phylogeny

The evolutionary history of a group of organisms, ancestor --> descendant

Node

The point on a phylogenetic tree where a branch splits, representing where species diverged from common ancestor

Root

The most ancestral node or branch in a phylogenetic tree

Shared Derived Characteristics

Changes that are shared from every descendant right

Parsimony

The most likely phylogenetic tree has the fewest number of changes

Monophyletic Group

Includes ancestor, and all of its descendants (Everyone!)

Paraphyletic Group

Includes ancestors, but is missing at least one descendant

Polyphyletic Group

Has no common ancestors, all descendants are "random"

Homologous Traits

Similar traits due to same ancestor

Analogous Traits

Does not share a same ancestor, but groups still may be similar to one another

Convergent Evolution

Creates analogous traits, same selective pressures make similar traits

Co-evolution

One population's evolution influences the evolutionary trajectory of another (Predator/Prey dynamic)