How do you DO classification?

1
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

2
How do you DO classification?

• Sharing our Results

3
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

4
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
5
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
6
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
7
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
8
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
9
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
10
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
11
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
12
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
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

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
15
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
16
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
17
The Forest Meet!
But Wait! We have one really-slow runner just
exiting! Here is his cardfigure out his pathway
18
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
19
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
20
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
21
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

22
OG A B C D E
0 0 1 0 0 1
0 0 0 1 0 0
0 1 0 0 0 0
0 1 1 1 1 1
0 0 1 0 0 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 1 1 1 1
23
OG A B C D E
0 0 1 0 0 1
0 0 0 1 0 0
0 1 0 0 0 0
0 1 1 1 1 1
0 0 1 0 0 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 1 1 1 1
We start with our most-synapomorphic character
ABCDE
OG
-- wide wing -- long tail
24
OG A B C D E
0 0 1 0 0 1
0 0 0 1 0 0
0 1 0 0 0 0
0 1 1 1 1 1
0 0 1 0 0 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 1 1 1 1
We continue with our next-most-synapomorphic
character
ACD
BE
-- heavy leg -- wide body
OG
-- wide wing -- long tail
25
OG A B C D E
0 0 1 0 0 1
0 0 0 1 0 0
0 1 0 0 0 0
0 1 1 1 1 1
0 0 1 0 0 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 1 1 1 1
We continue with our least-synapomorphic character
CD
A
BE
-- long leg -- dark body
-- large eye
-- heavy leg -- wide body
OG
-- wide wing -- long tail
26
OG A B C D E
0 0 1 0 0 1
0 0 0 1 0 0
0 1 0 0 0 0
0 1 1 1 1 1
0 0 1 0 0 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 0 1 1 0
0 0 0 1 1 0
0 1 1 1 1 1
We finish with our autapomorphic character
C
D
B
E
A
-- black eye
-- long wing
-- wide neck
-- long leg -- dark body
-- large eye
-- heavy leg -- wide body
OG
-- wide wing -- long tail
27
Finally we format our cladogram with extant taxa
at the top
OG E B
A D C
-- black eye
-- wide neck
-- long wing
-- long leg -- dark body
-- large eye
-- heavy leg -- wide body
-- wide wing -- long tail
28
What do we do with the swapped out Clade Critter?
OG E B
A D C
-- black eye
-- wide neck
-- long wing
-- long leg -- dark body
-- large eye
-- heavy leg -- wide body
-- wide wing -- long tail
29
What do we do with the swapped out Clade Critter?
OG E B
A D C
-- black eye
dark -- body
-- wide neck
-- long wing
-- long leg -- dark body
-- large eye
-- heavy leg -- wide body
A homoplasy A parallelism or. A convergence
-- wide wing -- long tail
30
Is there an alternative explanation?
OG E B
A D C
-- dark bodyR
-- black eye
dark -- body
-- long wing
-- wide neck
-- long leg -- dark body
-- dark bodyR
Two evolutions
-- large eye
-- heavy leg -- wide body
A single evolution But two reversals
-- dark body
-- wide wing -- long tail
Is it easier to evolve or to lose the
characteristic?