How Long Ago?

Mul

ticell

ular

Animals

Myx

ozoa

ns

Proto

zoan

s

Trache

ophy

tes

Bryop

hytes

True F

ungi

Slime M

olds

Red al

gae

Brown A

lgae

Green A

lgae

Chrys

ophy

tes

Euglen

oids

Archez

oans

Archae

bacte

ria

Bacter

ia

Original Cell

Extant

Extinct

Long Time with

Prokaryotes only

0.5

1

2

3

4 BYBPOrigin of Life

Cyanobacterial Oxygen

First Eukaryotes

Multicellular

AnimalsLand!

Evidence Categories

• History - clearer recently, more obscure anciently

• Fossils - stratigraphic depth, isotope decay, etc.

• Chemical - metabolic products such as O2, Ss

• Molecular - DNA sequence alterations, etc.

• Developmental sequences - onto- phylo- geny

• Biogeography - Pangea, Gondwana & Laurasia

How do we know the Evolution Pathway?Phylogenetic Systematics

Inferences from comparison of extant organismsCharacters-Attributes of the organism

»Anatomy»Morphology»Development»Physiology»Macromolecule Sequences

Polarizing Character States•Plesiomorphies-Ancient, shared by descendants•Apomorphies-More-recent derivatives

»Synapomorphy-Shared among related organisms»Autapomorphy-Found only in one organism

•Use of outgroup to compare to ingroup

Typical Cladogram

CommonAncestor

Extant APresent

Ancient

ExtinctTransitionalForms

Time

A’

A”

A’” This straight line of evolution is called anagenesis.

Extant B

This branching of evolution is called cladogenesis.

A’ is the common ancestor of extant A and extant B

Typical Cladogram

CommonAncestor

Extant A Extant BPresent

Ancient

Time

A’

A”

A’”

Extant C

A” C are a grade (is paraphyletic)

A” C A’ A B are a clade

A’ A B is the sister group of C

A’ A B constitute a clade

Typical Cladogram

CommonAncestor

Extant A Extant CExtant BPresent

Ancient

Time

A’

A”

A’”

A””Extinct!

Extant D Extant E

A””’

D A””’ E are a ?clade

Common ancestor + A””’ D E are a ?grade

The ABC clade may be, say, a genus.The DE clade may be another genus… in the same family

The ABCDE clade would be the family

Typical Cladogram

CommonAncestor

Extant A Extant C Extant D Extant EExtant BPresent

Ancient

Time

A’

A”

A’”

A””Extinct!

A””’

On the otherhand…

AB are a genusC is a monotypic genusDE are a genus

ABC might be one familyDE are in another family

ABCDE might constitute an order

Mul

ticell

ular

Animals

Myx

ozoa

ns

Proto

zoan

s

Trache

ophy

tes

Bryop

hytes

True F

ungi

Slime M

olds

Red al

gae

Brown A

lgae

Green A

lgae

Chrys

ophy

tes

Euglen

oids

Archez

oans

Archae

bacte

ria

Bacter

ia

Original Cell

Extant

Extinct

Living organisms are part of one clade

Eukaryotic organisms are a clade

Prokaryotic organisms are a grade (paraphyletic)

Protists are polyphyletic (unnatural taxon)

Plants are a clade (monophyletic)

Animals andFungi are a clade!

How do you DO classification?

1. Get with a partner to form a team2. Look over the cards you are given for your team3. Every group gets the same set of 8 cards

• Bob• Sue• Deb• Lou• Jen• Cal• Hal• Val

4. Sort the cards into what you believe may be natural groups• Names do not count, use only shapes shown on card

5. Decide who will tell the class how you sorted your groups• What theme unites/defines each group

Warmup!

How do you DO classification?

Sharing our Results

1. This game is a cross-country race in a forest2. All runners enter the forest by a single south entrance3. The finish line is the northern boundary of the forest4. Runners need not exit at any particular place at the finish5. There are many trails through the woods

• Trails only bifurcate (form two branches) at forks• Trails never join together or rejoin after forking

6. Along the trail straightaways are check-in stations7. At each check-in station, a worker has a unique stamp8. Each runner has a card that is stamped as s/he passes a station9. Runners are not allowed to retrace a path10. All runners must finish the race11. Using the punch cards handed in at the finish line:

• Sketch the trail map• Show all station locations (on the straightaways)• Mark the exit used by each runner

The Forest Meet!

Bob Sue Deb Lou Jen Cal Hal Val

x x x x x x x x

x x x x x

x x

x

x x x x

x x

x

x x

x

x x x

x

x

The Forest Meet Sharing our Results

Bob Sue Deb Lou Jen Cal Hal Val Total

x x x x x x x x 8

x x x x x 5

x x 2

x 1

x x x x 4

x x 2

x 1

x x 2

x 1

x x x 3

x 1

x 1

The Forest Meet Sharing our Results

The Forest Meet Sharing our ResultsRunners can finish anywhere along this northern edge

Start

All of the runners passed the circle station, so this station

must be near the start

Bob Sue Deb Lou Jen Cal Hal Val Total

x x x x x x x x 8

x x x x x 5

x x 2

x 1

x x x x 4

x x 2

x 1

x x 2

x 1

x x x 3

x 1

x 1

The Forest Meet Sharing our Results

The Forest Meet Sharing our ResultsRunners can finish anywhere along this northern edge

Start

Five of the runners passed the teardrop station, but three did

not, so our 8 runners must have divided into two groups

Sue, Lou, Jen, Hal, ValBob, Deb, Cal

Bob Sue Deb Lou Jen Cal Hal Val Total

x x x x x x x x 8

x x x x x 5

x x 2

x 1

x x x x 4

x x 2

x 1

x x 2

x 1

x x x 3

x 1

x 1

The Forest Meet Sharing our Results

The Forest Meet Sharing our ResultsRunners can finish anywhere along

this northern edge

Start

Four runners of the group of five passed the diamond

station, but Hal did not, so he split away before this station

Sue, Lou, Jen, Val

Bob, Deb, Cal

Hal

Because paths do not rejoin, Hal is separated and thus we can draw him at the finish line

Sue, Lou, Jen, Hal, Val

Bob Sue Deb Lou Jen Cal Hal Val Total

x x x x x x x x 8

x x x x x 5

x x 2

x 1

x x x x 4

x x 2

x 1

x x 2

x 1

x x x 3

x 1

x 1

The Forest Meet Sharing our Results

The Forest Meet Sharing our ResultsFinish Line

Start

Sue, Lou, Jen, Val

Bob, Deb, Cal

Hal

Bob, Deb, and Cal all passed the triangle

station so it was along the path they shared

Bob Sue Deb Lou Jen Cal Hal Val Total

x x x x x x x x 8

x x x x x 5

x x 2

x 1

x x x x 4

x x 2

x 1

x x 2

x 1

x x x 3

x 1

x 1

The Forest Meet Sharing our Results

The Forest Meet Sharing our ResultsFinish Line

Start

Sue, Val

Deb, Cal

Hal

Deb, and Cal passed the star station, but Bob did not, so the group divided

Jen, Lou

Bob

Jen and Lou passed the heart station, but Sue and Val passed the spade station, so the group

of four divided

Bob, Deb, Cal

Sue, Lou, Jen, Val

The Forest Meet The rest are autapomorphiesBob Sue Deb Lou Jen Cal Hal Val Total

x x x x x x x x 8

x x x x x 5

x x 2

x 1

x x x x 4

x x 2

x 1

x x 2

x 1

x x x 3

x 1

x 1

The Forest Meet Autapomorphies!

Start

Hal

Bob

Cal Deb Jen Lou Sue Val

Deb, Cal

Jen, Lou Sue, Val

Notice the runners are in alphabetical order. But this is not the only solution

All branches can be rotated:e.g.: Lou before JenSue-Val before Jen-Lou

But Wait!

We have one really-slow runner just exiting!

Here is his card…figure out his pathway

The Forest Meet!

Bob Sue Deb Lou Jen Cal Hal Val Ross

x x x x x x x x x

x x x x x x

x x

x

x x x x

x x

x x

x x

x

x x x

x

x x

The Forest Meet Sharing our Results

The Forest Meet

Start

Hal

Bob

Cal Deb Jen Lou Sue Val

What did Ross do?What is parsimonious?Are our ideas wrong?

Maybe Ross followed Hal..Then hit a rougue station?

Ross

1. This game is a cross-country race in a forest2. All runners enter the forest by a single south entrance3. The finish line is the northern boundary of the forest4. Runners need not exit at any particular place at the finish5. There are many trails through the woods

• Trails only bifurcate (form two branches) at forks• Trails never join together or rejoin after forking

6. Along the trail straightaways are check-in stations7. At each check-in station, a worker has a unique stamp8. Each runner has a card that is stamped as s/he passes a station9. Runners are not allowed to retrace a path10. All runners must finish the race11. Using the punch cards handed in at the finish line:

• Sketch the trail map• Show all station locations (on the straightaways)• Mark the exit used by each runner

The Clade Race!1. This game represents the evolution of some related organisms2. The organisms are believed to be a clade (w/common ancestor)3. The organisms we are using are all extant (none are fossils)

5. We make few assumptions about the evolution pathway • Cladogenesis divides one species into two species • We assume there is no convergent or parallel evolution

6. Anagenesis is expected to occur between generations 7. Evolution shows its record of changes in the genotype 8. The record of evolution in genotype is shown in the phenotype9. Evolution is permanent; we assume no reversals of states 10. In this study, we are using no fossils of extinct clade members11. Using the phenotypes observed in the extant organisms:

4. We make no assumptions about possible phenotypes observed

• Sketch the cladogram• Show the location of character state transitions • Show the relationships among the taxa

How do you DO cladistics?1. Look at a group of organisms that you think are related

2. Find a not-too-distantly related (primitive?) out-group

3. Select characters that will help to distinguish the organisms

4. Polarize the character states by:• Stratigraphic sequence (fossil sequence)• Developmental sequence (ontogeny recaps phylogeny)• Outgroup comparison

5. Build a data matrix

6. Group by number of synapomorphies (shared derived)

7. Sketch possible cladograms

8. Seek simplest (most parsimonious) cladogram