Transcript Evidence for Evolution

Evidence for Evolution
A slide extravaganza…
Types of evidence…
1. Evidence from the fossil record
(dead things)
Fossil formation
Bones and shells undergo mineral
replacement and are turned into rock
Soft material either disappears, or leaves
an impression in the earth (that turns to
rock)
A selection of fossils…
Fossils show transitions
The Archaeopterix -- between reptile and bird
Scallops
From early to modern horse
(Living things show
transitions too)
Coelacanths - “the living
fossil”
Types of evidence…
1. Evidence from the fossil record
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
A. Homologous Structures
Homo - logy
Homologous structures have the same underlying
forms
Wing anatomy comparison
And compared to our arm…
Arm anatomy comparison
B. Analogous Structures
Ana - logy
Analogous structures have a similar outward
appearance (but different underlying forms)
Types of evolution
Convergent evolution
Distantly related
organisms evolve similar
external features
Divergent evolution
A common ancestor gives
rise to organisms that
evolve for different
environments
Which goes with which? ….
Homologous structures
Analogous structures
Convergent evolution
Distantly related
organisms evolve similar
external features
Divergent evolution
A common ancestor
gives rise to organisms
that become more
different with time.
Which goes with which?
Homologous structures
Analogous structures
Convergent evolution
Distantly related
organisms evolve similar
external features
Divergent evolution
A common ancestor
gives rise to organisms
that become more
different with time.
C. Vestigial Structures
Vestige - a left-over/ remnant
Vestigial structures are evolutionary “leftovers”
from an earlier ancestor
The “dew” claw of a wild cat
The human appendix
Rabbit
Fetal Human
Adult Human
Membranes in our eyes
Hip bones in whales
(Look at that “hand” too!)
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
3. Comparative Embryology
Human embryo at 5 weeks
Embryos…
…can you guess which one is human?
Embryos…
…how about now?
And now…
Were you right?
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
3. Comparative Embryology
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
Comparing DNA…
Determining relationships
DNA similarity between species is used to
determine how closely related they are.
This is in turn used to construct possible
evolutionary trees.
How closely related are
these fellows?
Mystery critter! (I’m not telling)
Brown Bear
…got your guess?
Giant Panda
An Evolutionary Tree
This tree was constructed by looking at % similarity of DNA among “bears”
…so why is he called a red panda?
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
5. Behavior
Behavioral similarities
Duck and other bird mating dances
How primates carry their young
Fish swimming motions and salamander
walks
And on and on and on….
Types of evidence…
1. Evidence from the fossil record
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
5. Behavior
Types of evidence…
1. Evidence from the Fossil Record
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
5. Behavior
6. Direct observation
 also known as microevolution
Artificial selection
Remember us?
And look at us!
And Natural Selection
Hawaiian Rock Wallabies!
The Beak of the Finch
Biologists Peter and Rosemary
Grant documented natural
selection occurring in populations
of finches on the Galapagos
islands over a period of only 20
years! This generation to
generation changes in the
frequency of certain traits is
called microevolution.