1. Evidence for Evolution by Natural Selection

2. Vocabulary
Analogous Convergent evolution Embryo Homologous Vestigial

3. What are the lines of evidence that support Darwin’s ideas?…10 20 30 40 50 60 70 80 90
100
110
120
Lamprey
Frog
Bird
Dog
Macaque
Human 32 8 45 67
125
Fossil Record

4. Evidence of Evolution
Darwin argued that life on earth has been evolving for millions of years. 1. Artificial Selection 2. The Fossil Record 3. Geographical location 4. Anatomical evidence 5. Similarities in Early Development 6. DNA and protein similarities (newer evidence)

5. 1)Artificial selection
What are the lines of evidence that support Darwin’s ideas?
Terminal
bud
Lateral
buds
Brussels sprouts
Cabbage
Flower cluster
Leaves
Cauliflower
Flower
and
stems
Broccoli
Wild mustard
Kohlrabi
Stem
Kale
1)Artificial selection
Artificial selection
Hidden variation can be exposed through selection!

6. Selective breeding
the raw genetic material (variation) is hidden there

7. What are the lines of evidence that support Darwin’s ideas?
2) Fossil record
Millions of years ago 50
100
150
200
250
300
350
400
450
500
550 60 55 45 40 35 30 25 20 15 10 5
Equus
Hyracotherium
Mesohippus
Merychippus
Nannippus
Body size (kg)
sedimentary rock
sequence: older fossls on bottom, younger fossls on top

8. The Fossil Record

9. Evidence for Evolution – The Fossil Record
Darwin and His Theory
Evidence for Evolution – The Fossil Record
4/25/2017
G. Podgorski, Biol. 1010

10. The Fossil Record
Showed that:
There have been countless species that have lived on earth but no longer live on earth today
Layers of rocks with fossils demonstrated that thousands, or even millions of years were needed to create this
Species have changed in appearance and complexity

11. The fossil record
The giant sloth

13. Evolution of birds Archaeopteryx lived about 150 mya
links reptiles & birds
The avian nature of the brain and inner ear of Archaeopteryx (Alonso et al. 2004) - Archaeopteryx, the earliest known flying bird from the Late Jurassic period, exhibits many shared primitive characters with more basal coelurosaurian dinosaurs (the clade including all theropods more bird-like than Allosaurus), such as teeth, a long bony tail and pinnate feathers. However, Archaeopteryx possessed asymmetrical flight feathers on its wings and tail, together with a wing feather arrangement shared with modern birds. This suggests some degree of powered flight capability but, until now, little was understood about the extent to which its brain and special senses were adapted for flight. Alonso et al. (2004) investigated this problem by computed tomography scanning and three-dimensional reconstruction of the braincase of the London specimen of Archaeopteryx. A reconstruction of the braincase and endocasts of the brain and inner ear suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. Alonso et al. (2004) concluded that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability.
Smithsonian Museum, Washington, DC

14. Evolution of land animals
2006 Fossil Discovery of Early Tetrapod
“Tiktaalik”
“missing link” from sea to land animals
from swimming (0 legs) to walking (4 legs)

15. 3. Geographic Distribution of Living Species
Animals that are related to each other showed ‘descent with modification’ based on their environment (even though probably closely related, looked different because different environment
Animals that were not related to each other looked similar if they were from similar environments.

16. Geographic Distribution of Living Species
Example: Based on what they look like: Which two animals do you think are more closely related to one another?
Desert Fox Koala Dingo

17. Geographic Distribution of Living Species
Believed to not be closely related to each other even though they look more alike.
Evolutionists say they look alike because they live in the same kind of environment so over time they adapted in similar ways
Desert Fox Dingo

18. Analogous structures Dissimilar anatomy doing a similar function
Convergent
evolution
Don’t be fooled by their looks!
same function different development & anatomy
Those fins & tails & sleek bodies are analogous structures!
convergent evolution - NOT common ancestor
Those fins & tails
& sleek bodies are analogous structures!
Does this mean they have a recent common ancestor?
Dissimilar anatomy doing a similar function

19. What is this evidence of?
Convergent evolution
What is this evidence of?
These animals look very similar but does that mean they have a recent common ancestor?
marsupial
mammals
Biogeographical evidence
No!
Convergent / parallel evolution similar environments & niches lead to natural selection of similar traits
placental
mammals

20. What are the lines of evidence that support Darwin’s ideas?
4) Anatomical evidence
Anatomical evidence
1. These structures are called… homologous
2. These structures are evidence for…. common ancestry
3. similar internal structure = similar development
4. different function = different environment & niche
5. close evolutionary r’ship!

22. Homologous Structures
Arms, wings, legs, and flippers all have very similar bones
Similar in anatomy doing different potentially different functions
Darwin believed this was evidence that all species were original descended from one common ancestor.

23. Homologous structures
spines
leaves
succulent leaves
tendrils
needles
colored leaves

24. Why would whales have pelvis & leg bones if they were always sea creatures?
These are remnants of structures that were functional in ancestral species
Vestigial organs
Humans
Appendix
Coccyx
Wisdom Teeth
Darwin’s Tubercle (ear)
Palmaris Longus
Goose bumps
Pseudogenes – L-gulonolactone oxidase
Remains of ancestral structures = mutations can occur without affecting survival & reproduction
Evolutionary relationship
snakes & whales — remains of pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone

25. Vestigial Organs Humans Appendix Coccyx Wisdom Teeth
Darwin’s Tubercle (ear)
Palmaris Longus
Goose bumps

26. 5. Similarities in Early Development
Looking at the embryonic development of organisms Darwin noticed some similarities that other scientists also noticed.

27. Evidence for Evolution - Comparative Embryology
Darwin and His Theory
4/25/2017
Evidence for Evolution - Comparative Embryology
Why do embryos of different animals pass through a similar developmental stage?
G. Podgorski, Biol. 1010

28. Comparative hemoglobin structure
6. Putting it all together with DNA evidence
Why compare DNA & proteins across species?
The sequence in DNA & proteins is a molecular record of evolutionary relationships. 10 20 30 40 50 60 70 80 90
100
110
120
Lamprey
Frog
Bird
Dog
Macaque
Human 32 8 45 67
125
Comparative hemoglobin structure
Molecular Record
What are we comparing here? - comparing DNA (base sequence) & proteins (amino acid sequence)
What assumption do we make about genes and relatedness?  the more closely related, the more DNA bases & amino acids you have in common
have to compare genes for protein the organisms have in common… can’t compare genes for proteins you don’t have
Why compare these genes?
compare common genes
cytochrome C (respiration)
hemoglobin (gas exchange)
Number of amino acid differences between
hemoglobin (146 aa) of vertebrate species and that of humans

29. Building “family” trees
Closely related species (branches) share same line of descent until their divergence from a common ancestor