A branching tree has often been used as a metaphor for descent from a common ancestor.

Each branch point (node) representsa common ancestor of everyoneabove that node on the tree.

The end of every branch representsThe “final product” of that descent From a common ancestor.

Aristotle believed that life was organized in a hierarchy

But remember: Evolution is NOT like a ladder

There is no “pinnacle” of evolution.

Instead, evolution is more like a branching tree.

A species’ phylogeny is its evolutionary history.

The base of the tree is the common ancestor

The nodes are also common ancestors

A phylogeny is a hypothesis.

The study of the evolutionary relationships among organisms

The goal: classify on the basis of recency of common descent

i.e., who shared the most recent common ancestor?

The science of naming and classifying organisms

The Father of Modern Taxonomy: Carl Linne

(a.k.a. Carollus Linnaeus)

Full title: › Systema Naturae: Creationis telluris est

gloria Dei ex opere Naturae per Hominem solum.

This last part translates as › "The Earth's creation is the glory of God, as

seen from the works of Nature by Man alone.”

related species are grouped in the same genus (plural, genera)

related genera are grouped in the same family related families are grouped in the same order related orders are grouped in the same class related classes are grouped in the same phylum

(plural, phyla) related phyla are grouped in the same kingdom related kingdoms are grouped in the same

domain

Carl Woese used ribosomal RNA to determine that there were three major groups of organisms that were EACH descended from a common ancestor.

All the other groups in thehierarchy arenested withinone of the threeDOMAINS.

A taxon (plural = taxa) is a group of organisms related by evolutionary descent from a common ancestor.

The more closely related two species are, the more similar characteristics they will share.

Species descended from a common ancestor have shared, derived characteristics (a.k.a. characters)

Every species has its own unique scientific name

It consists of its genus (capitalized) And species (lower case) The name is italicized. Homo sapiens

HOMOLOGOUS characters are shared between species because they were inherited from a common ancestor.

ANALOGOUS characters have a similar function in two species, but were not inherited from a common ancestor.

PRIMITIVE characters have been inherited from a common ancestor, but are not very changed from the ancestral form.

Example: All vertebrates have a bony tail posterior to the anus.

PRIMITIVE characters are also called PLESIOMORPHIES.

plesio means “near” in Greek

morph means “form” or “shape”

A symplesiomorphy is a primitive character shared by two or more taxa.

Like the post-anal tail shared here.

DERIVED characters have been inherited from a common ancestor, but have diverged in form among species

Example: Great apes have reduced tails, compared to other vertebrates.

DERIVED characters are also called APOMORPHIES.

apo means “away” in Greek.

morph means “shape” or “form”

A synapomorphy is a shared, derived character.

Like the reduced tail shared only by apes, not other primates.

1a – made of metal……………….go to 2 1b – made of paper………………..go to 5 2a – brown (copper)………………penny 2b – silver……………………………go to 3 3a – smooth edge…………………nickel 3b – ridged edge………………….go to 4 4a – torch on back………………..dime 4b – eagle on back……………….quarter

Notice that they share some traits, but some share more traits than others.

Your job: use the provided taxonomic key to identify your pasta samples to the correct “species”.

A good taxonomic key can reflect evolutionary relationships by using shared, derived characters.

With various “species” of hardware. Each team will create a phylogenetic tree Each team will create a taxonomic key MAY THE BEST TEAM WIN!