Lab 3: Describing Evolutionary History

Taxonomy

giving unique and meaningful names to all species on Earth and organizing those names in a meaningful way (classification).

Systematics

science of naming & identifying evolutionary or phylogenetic relationships among species.

Bacteria

Unicellular (mostly)

small

no membrane bound organelles

Archaea

Unicellular (mostly)

small

no membrane bound organelles

extreme environments

Eukarya

Unicellular or multicellular

Larger

Membrane-bound organelles

Nucleus (Eu=true, karya=kernal

Prokaryotes

Bacteria and Archaea
No nucleus or membrane- bound organelles

Eukarya

Nucleus and membrane- bound organelles

Unikonta (Supergroups)

animals, fungi, and others

Archaeplastida (Supergroup)

Land Plants & others

Phylogenetic Trees

Show a pattern of ancestry and descent

Tips

represent the extant (living) species

Branches

relationships among the tips (species) of the tree

Nodes

– identify a recent common ancestor that is extinct (branching points)

Basal node

oldest shared ancestor in the phylogeny.

Outgroup

– root of the tree that identifies the most distantly related species to all of the rest of the species

Polytomy

multiple branches at one node. Shows that the pattern of relationships is unclear

Clades

An ancestor and ALL its descendants.

Synapomorphy-

shared derived trait.
Trait that defines a clade.

Homologous traits

Similar due to shared ancestry

Analogous traits

similar, but do not have shared ancestry.