1. Vocabulary – Add to Word Wall
65. Fossil – Traces of organisms that lived in the past
66. Gradualism – Organisms evolve through a process of slow and constant change
67. Punctuated Equilibrium – Species evolve very rapidly and then stay the same for a large period of time

2. 68. Derived Character – Characteristics that appear more recently in a group but not seen in older organisms
69. Vestigial Structures – Structures that have lost or reduced their function
70. Fitness – The ability of an individual to survive and reproduce in its specific environment
71. Adaptation – Any inherited characteristic that increases an organism’s chance of survival

3. 72. Survival of the Fittest – Individuals that are better suited to their environment, survive and reproduce most successfully.
73. Gene Pool – Combined genetic information of all the members of a particular population

4. Evidence for Evolution by Natural Selection
Hunting for evolution clues… Elementary, my dear, Darwin!

5. Evidence supporting evolution
1. Fossil record
shows change over time
2. Anatomical record
comparing body structures
homology & vestigial structures
embryology & development
3. Molecular record
comparing protein & DNA sequences
4. Artificial selection
human caused evolution

6. 1. Fossil record Layers of rock contain fossils
new layers cover older ones
fossils show a record of organisms living over time
over a long period of time

7. Life on Earth has changed
Fossils tell a story…
the Earth is old
Life is old
Life on Earth has changed

8. Evolution of birds Today’s organisms descended from ancestral species
Fossil of 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.

9. We found the fossil — no joke!
Land Mammal ?
Complete series of transitional fossils ?
Where are the intermediate fossils? ? ?
There are innumerable intermediate & transitional forms
Whales as land creatures returning to the water….
Where are the intermediate forms of whale ancestors?
Cartoon making fun of this idea.
The cartoons disappeared years ago when this fossil was found.
Ambilocetic natans = “Walking whale who likes to swim”
4-5 intermediate forms all found in last 2 decades
Indus River valley in between India & Pakistan.
Someone’s idea of a joke!
Ocean Mammal
But the joke’s on them!!

10. Evolution from sea to land
2006 fossil discovery of early tetrapod
4 limbs
Missing link from sea to land animals

11. 3. Anatomical record Animals with different structures on the surface
But when you look under the skin…
It tells an evolutionary story of common ancestors

12. How could these very different animals have the same bones?
Compare the bones
The same bones under the skin
limbs that perform different functions are built from the same bones
How could these very different animals have the same bones?

13. Homologous structures
Structures that come from the same origin
homo- = same
-logous = information
Forelimbs of human, cats, whales, & bats
same structure
on the inside
same development in embryo
different functions
on the outside
evidence of common ancestor

14. But don’t be fooled by these…
Analogous structures
look similar
on the outside
same function
different structure & development
on the inside
different origin
no evolutionary relationship
How is a bird like a bug?
Solving a similar problem with a similar solution

15. Analogous structures Dolphins: aquatic mammal Fish: aquatic vertebrate
both adapted to life in the sea
not closely related
Watch the tail!

16. They just came up with the same answer!
Flight evolved 3 separate times —
evolving similar solutions to similar “problems”
Convergent evolution
3 groups with wings
Does this mean they have a recent common ancestor?
They just came up with the same answer!
NO!

17. Convergent evolution led to mimicry
Why do these pairs look so similar?
Monarch male
poisonous
Viceroy male
edible
Which is the moth vs. the bee?
Which is the fly vs. the bee?
fly
bee
moth
bee

18. Because they used to walk on land!
Vestigial Structures
Ex. Hind leg bones on whale fossils
Why would whales have pelvis & leg bones if they were always sea creatures?
Because they used to walk on land!

19. Comparative embryology
Development of embryo tells an evolutionary story
Compares and contrasts embryos of different species
similar structures during development
all vertebrate embryos have a “gill pouch” at one stage of development

20. 3. Molecular record Comparing DNA & protein structure between species
everyone uses the same genetic code!
DNA 10 20 30 40 50 60 70 80 90
100
110
120
Lamprey
Frog
Bird
Dog
Macaque
Human 32 8 45 67
125
compare common genes
compare common proteins
number of amino acids different from human hemoglobin

21. Building “family” trees
Closely related species are branches on the tree — coming from a common ancestor

22. “descendants” of wild mustard
4. Artificial selection
How do we know natural selection can change a population?
Humans recreate a similar process
“evolution by human selection”
“descendants” of wild mustard

23. “descendants” of the wolf
Selective Breeding
Humans create the change over time
“descendants” of the wolf

24. I liked breeding pigeons!
Artificial Selection
…and the examples keep coming!
I liked breeding pigeons!

25. Artificial Selection gone bad!
Unexpected consequences of artificial selection
Pesticide resistance
Antibiotic resistance

26. Insecticide resistance
Spray the field, but…
insecticide didn’t kill all individuals
variation
resistant survivors reproduce
resistance is inherited
insecticide becomes less & less effective
The evolution of resistance to insecticides in hundreds of insect species is a classic example of natural selection in action.
The results of application of new insecticide are typically encouraging, killing 99% of the insects.
However, the effectiveness of the insecticide becomes less effective in subsequent applications. The few survivors from the early applications of the insecticide are those insects with genes that enable them to resist the chemical attack. Only these resistant individuals reproduce, passing on their resistance to their offspring. In each generation the % of insecticide-resistant individuals increases.

28. Any Questions??

29. Natural Selection of Strawfish
How does natural selection affect genes?
How do genes affect evolution?

30. 1. No Predator Preferences
FISH
ALLELES
blue
green
yellow
Gen. 1
25%
50%
Gen. 4
27%
55%
18%
45%
No selection force in one specific direction.
No clear pattern of change.

31. 2. Predator Prefers BLUE 25% 50% 13% 37% 38% 62%
FISH
ALLELES
blue
green
yellow
Gen. 1
25%
50%
Gen. 4
13%
37%
38%
62%
Selection against blue.
Fewer blue fish and fewer blue alleles.

32. 3. Predator Prefers GREEN
FISH
ALLELES
blue
green
yellow
Gen. 1
25%
50%
Gen. 4
36%
28%
Selection against green.
Fewer green fish but same variation in alleles.

33. 4. GREEN is Camouflaged 25% 50% 20% 60%
FISH
ALLELES
blue
green
yellow
Gen. 1
25%
50%
Gen. 4
20%
60%
Selection against blue & yellow.
More green fish but same variation in alleles.

34. Australian Marsupials
Parallel Evolution
Niche
Placental Mammals
Australian Marsupials
Burrower
Mole
Anteater
Mouse
Lemur
Flying
squirrel
Ocelot
Wolf
Tasmanian “wolf”
Tasmanian cat
Sugar glider
Spotted cuscus
Numbat
Marsupial mole
Marsupial mouse
Nocturnal
insectivore
Climber
Glider
Stalking
predator
Chasing
not closely related
marsupial
mammal
placental
filling similar roles in nature, so have similar adaptations