How Long Ago?

1
How Long Ago?
Extant
Animals
Land!
Multicellular
First Eukaryotes
Extinct
Cyanobacterial Oxygen
Long Time with Prokaryotes only
Origin of Life
Original Cell
2
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

3
How do we know the Evolution Pathway?
Phylogenetic Systematics

• Inferences from comparison of extant organisms
• Characters-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

4
Typical Cladogram
Extant A
Present
This branching of evolution is called
cladogenesis.
Extinct Transitional Forms
A is the common ancestor of extant A and extant B
Time
This straight line of evolution is called
anagenesis.
Common Ancestor
Ancient
5
Typical Cladogram
Extant A
Extant B
Present
A
A A B constitute a clade
A C are a grade (is paraphyletic)
A
Time
A C A A B are a clade
A
A A B is the sister group of C
Common Ancestor
Ancient
6
Typical Cladogram
Present
A
D A E are a ? clade
Common ancestor A D E are a ? grade
A
Time
A
The ABC clade may be, say, a genus. The DE clade
may be another genus in the
same family
Common Ancestor
Ancient
The ABCDE clade would be the family
7
Typical Cladogram
Extant A
Extant C
Extant D
Extant E
Extant B
Present
A
On the other hand
A
AB are a genus C is a monotypic
genus DE are a genus
Extinct!
A
Time
A
A
ABC might be one family DE are in another family
Common Ancestor
Ancient
ABCDE might constitute an order
8
Protists are polyphyletic (unnatural taxon)
Extant
Animals and Fungi are a clade!
Plants are a clade (monophyletic)
Extinct
Eukaryotic organisms are a clade
Prokaryotic organisms are a grade (paraphyletic)
Living organisms are part of one clade
Original Cell
9
How do you DO classification?
Warmup!

• Get with a partner to form a team
• Look over the cards you are given for your team
• Every group gets the same set of 8 cards
• Bob
• Sue
• Deb
• Lou
• Jen
• Cal
• Hal
• Val
• Sort the cards into what you believe may be
  natural groups
• Names do not count, use only shapes shown on card
• Decide who will tell the class how you sorted
  your groups
• What theme unites/defines each group

10
How do you DO classification?

• Sharing our Results

11
The Forest Meet!

• This game is a cross-country race in a forest
• All runners enter the forest by a single south
  entrance
• The finish line is the northern boundary of the
  forest
• Runners need not exit at any particular place at
  the finish
• There are many trails through the woods
• Trails only bifurcate (form two branches) at
  forks
• Trails never join together or rejoin after
  forking
• Along the trail straightaways are check-in
  stations
• At each check-in station, a worker has a unique
  stamp
• Each runner has a card that is stamped as s/he
  passes a station
• Runners are not allowed to retrace a path
• All runners must finish the race
• 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

12
The Forest Meet

• Sharing our Results

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
13
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
14
The Forest Meet

• Sharing our Results

Runners can finish anywhere along this northern
edge
All of the runners passed the circle station, so
this station must be near the start
?
Start
15
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
16
The Forest Meet

• Sharing our Results

Runners can finish anywhere along this northern
edge
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, Val
Bob, Deb, Cal
?
?
Start
17
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
18
The Forest Meet

• Sharing our Results

Hal
Runners can finish anywhere along this northern
edge
Because paths do not rejoin, Hal is separated and
thus we can draw him at the finish line
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
Sue, Lou, Jen, Hal, Val
?
?
?
Start
19
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
20
The Forest Meet

• Sharing our Results

Hal
Finish Line
Bob, Deb, and Cal all passed the triangle station
so it was along the path they shared
Sue, Lou, Jen, Val
Bob, Deb, Cal
?
?
?
?
Start
21
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
22
The Forest Meet

• Sharing our Results

Hal
Bob
Finish Line
Jen and Lou passed the heart station, but Sue and
Val passed the spade station, so the group of
four divided
Deb, and Cal passed the star station, but Bob did
not, so the group divided
Sue, Val
Jen, Lou
Deb, Cal
?
?
Sue, Lou, Jen, Val
?
Bob, Deb, Cal
?
?
?
?
Start
23
The Forest Meet

• The rest are autapomorphies

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
24
The Forest Meet

• Autapomorphies!

Hal
Bob
Cal
Deb
Jen
Lou
Sue
Val
?
?
?
Jen, Lou
Sue, Val
Deb, Cal
?
?
?
?
?
?
Notice the runners are in alphabetical order. But
this is not the only solution
All branches can be rotated e.g. Lou before
Jen Sue-Val before Jen-Lou
?
?
?
Start
25
The Forest Meet!
But Wait! We have one really-slow runner just
exiting! Here is his cardfigure out his pathway
26
The Forest Meet

• Sharing our Results

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
27
The Forest Meet
Hal
Bob
Cal
Deb
Jen
Lou
Sue
Val
Ross
?
?
?
?
?
?
?
?
?
?
What did Ross do? What is parsimonious? Are our
ideas wrong?
?
?
Maybe Ross followed Hal.. Then hit a rougue
station?
?
Start
28
The Clade Race!

• This game is a cross-country race in a forest
• All runners enter the forest by a single south
  entrance
• The finish line is the northern boundary of the
  forest
• Runners need not exit at any particular place at
  the finish
• There are many trails through the woods
• Trails only bifurcate (form two branches) at
  forks
• Trails never join together or rejoin after
  forking
• Along the trail straightaways are check-in
  stations
• At each check-in station, a worker has a unique
  stamp
• Each runner has a card that is stamped as s/he
  passes a station
• Runners are not allowed to retrace a path
• All runners must finish the race
• 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

1. This game represents the evolution of some
related organisms
2. The organisms are believed to be a clade
(w/common ancestor)
3. The organisms we are using are all extant
(none are fossils)
4. We make no assumptions about possible
phenotypes observed
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 phenotype
9. Evolution is permanent we assume no reversals
of states
10. In this study, we are using no fossils of
extinct clade members
11. Using the phenotypes observed in the extant
organisms
Sketch the cladogram
Show the location of character state
transitions
Show the relationships among the taxa
29
How do you DO cladistics?

• Look at a group of organisms that you think are
  related
• Find a not-too-distantly related (primitive?)
  out-group
• Select characters that will help to distinguish
  the organisms
• Polarize the character states by
• Stratigraphic sequence (fossil sequence)
• Developmental sequence (ontogeny recaps
  phylogeny)
• Outgroup comparison
• Build a data matrix
• Group by number of synapomorphies (shared
  derived)
• Sketch possible cladograms
• Seek simplest (most parsimonious) cladogram