how long ago? multicellular animals myxozoansprotozoans tracheophytes bryophytes true fungi slime...
TRANSCRIPT
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