1. Vestigial Structures
Vestigial Structures are structures that are the reduced forms of functional structures in different species.
Examples:
1. Snake Pelvis: The pelvis is the attachment point for legs and is therefore nonfunctional in an animal without legs

2. Vestigial Structures
2. Kiwi Wing: The wings of kiwis are too small to be of any use in flight
3. Human Appendix: Important for digestion in many mammals, but of limited use in humans & some apes

3. What are some evidence of Evolution?
Analogous structures can be superficially similar in construction, but are NOT inherited from a common ancestor.
Example: The wing of an eagle & the wing of a insect have the same function (both enable the organism to fly) – but are constructed in different ways & from different materials.

4. What are some evidence of Evolution?
* While analogous structures do not indicate close evolutionary relationships, they do show that functionally similar features can evolve independently in similar environments.

5. Evidence #3: COMPARATIVE EMBRYOLOGY

6. Similarities in Early Development
What are some evidence of Evolution?
Similarities in Early Development
In their early stages of development, chickens, turtles, and rats look similar, providing evidence that they shared a common ancestry.

8. Evidence #4: COMPARATIVE BIOCHEMISTRY

9. What we know… All cells rely on DNA to make proteins.
Using new technologies, biologists are able to determine the amino acid sequences in proteins to determine evolutionary relationships among various species of organisms. 
The more closely related two species are, the greater the similarity in amino acid sequences of their proteins. 9

10. For example: 10

11. Evolution Video
Click here for video clip: Darwin, the Beagle, and Finches: Darwin Discovers Evidence of Natural Selection

12. Types of Evolution
There are 5 main types

13. Divergent Evolution:
When two species move away from the traits that they share with a common ancestor as they adapt to their own environments
Also called
Adaptive Radiation…
Produces
homologous structures,
And are more CLOSELY related!

14. Convergent Evolution:
When two distinct species with differing ancestries evolve to display similar features.
Sugar Glider:
Produces
analogous structures,
Australian marsupial
And are NOT closely related!
Flying Squirrel
A GA squirrel

15. **Coevolution**
Coevolution
Pollination

16. Geographic Distribution of Living Species
- Species now living on different continents had each descended from different ancestors.
- Because some animals on each continent were living under similar ecological conditions, they were exposed to similar pressures of natural selection.
They ended up evolving certain striking features in common…
but are NOT related!
This is called Convergent Evolution

17. Punctuated Equilibrium
Evolution that has long periods of stability or “unchange” followed by short periods of rapid change.

18. Gradualism
A change that is very slow over time. It’s hard to notice a difference over a short period of time…it is slow and gradual.

20. 5. Biological Resistance
Some organisms obtain a mutation that makes them resistant to a toxin (antibiotic or pesticide).
Overuse of antibiotics & pesticides create populations of “super bugs”.
This is why you need to take your antibiotics for the entire time…
You expose the bacteria to the toxin; but if you don’t kill them all (take all your medicine), then you “taught them” how to resist the antibiotic!

21. Resistance Explanation of how resistance happens:
Explanation of how bacteria transmit resistance:
Video about antibiotic resistance:

22. Generic Bell Curve for Natural Variation in a Complex Trait
5. Other patterns of selection
Frequency of Phenotype
Phenotype (height)
Generic Bell Curve for Natural Variation in a Complex Trait
Remember the graph…?

23. a. Stabilizing Selection
5. Other patterns of selection
  a. Stabilizing Selection
What good reasons can you come up with for this trend?
Human babies that have a really low birth weight…
Human babies that have a really high birth weight…
Stabilizing Selection
Key
Low mortality, high fitness
High mortality, low fitness
Selection against both extremes keep curve narrow and in same place.
Percentage of Population
Birth Weight

24. In stabilizing selection, the bulk portion of the bell-shaped curve is favored;
The average phenotype is favored

25. b. Directional Selection
Key
Directional Selection
Low mortality, high fitness
High mortality, low fitness
Food becomes scarce.

26. In directional selection, the one side of the bell-shaped curve is favored;
The one extreme phenotype is favored over the other, over the average

27. c. Disruptive Selection
Largest and smallest seeds become more common.
Key
Low mortality, high fitness
Population splits into two subgroups specializing in different seeds.
Number of Birds in Population
Number of Birds in Population
High mortality, low fitness
Beak Size
Beak Size

28. In disruptive selection, both end portions of the bell-shaped curve are favored;
Both extreme phenotypes are favored over the average

29. Adaptation:
body parts, body coverings, or behaviors that help an organism survive its environment or reproduce more effectively

30. Adaptations:
Mimicry: Adaptation in which one species evolves to resemble another species for protection or other advantages.

31. Adaptations: Camouflage: Adaptation that allows organisms to blend
into their surrounds.

32. Adaptations:
Imprinting: a form of learning in which a very young animal fixes its attention on the first object experience and then follows that object

33. Plants: Tropisms (Growth Responses):
1) Phototropism: Responds to light

34. Plants:
Tropisms (Responses):
2) Thigmotropism: Responds to touch

35. Plants: Tropisms (Responses): 3) Gravitropism: Responds to gravity
Click here for link to cool videos online.

36. Plants:
Tropisms (Responses):
4) Hydrotropism: Responds to water

37. Cactus Flowers: Can reproduce Sexually as well as asexually
Waxy Covering:
Prevent water loss
Ridges:
Expand to store more water when it rains
Thorns:
Protect against being eaten
No Leaves:
Prevent water loss

38. Catching prey/digging
Polar Bear
Thick Blubber:
Keep warm
Short/small Ears:
Save Heat
Large Paws:
Walking on snow
White/clear Fur:
Blend in with snow
Long Claws:
Catching prey/digging

39. Adaptation Prompt
Draw an organism and describe the adaptations that make it “fit” (as in ‘fitness,’ ‘survival of the fittest’).
1.) Organism must be drawn, in color, & neat
2.) Must include background environment
3.) Must have at least 3 adaptations w/ explanation of advantage for survival/reproduction
Not adaptations: How long they live, where they live, what they eat
Adaptation examples:
* Large paws, thick beak, bright colored feathers, skinny legs, large ears, sharp teeth, fur thickness….
Hint: Must be clearly related to survival or reproduction!!

40. Another example to demonstrate these selection patterns:

42. The End