1. Evidence
for
Evolution

2. Evidence for Evolution
Homology
Convergent evolution
Vestigial structures
Selective Breeding
Fossils
Embryology
DNA

3. Homology– Evidence of a Common Ancestor
All of these evobots used the same red pieces that were present in their ancestor but not in earlier generations.

4. Homology– Evidence of a Common Ancestor

5. Vertebrate Limb Homology

6. Homology– Evidence of a Common Ancestor
We can see the steps between the reptile jaw and the human ear– they use what appear to be the same bones.

7. Homology– Evidence of a Common Ancestor
When we see very similar parts in many living things, we gain evidence of their common ancestor and its characteristics.
This is especially true when similar parts have different functions

8. Convergent Evolution

9. Divergent Evolution
Most evolution appears to be divergent– those closest to the ancestral state are the most similar and organisms become more different as they evolve.
This is not always the case. Sometimes, organisms come up with similar solutions to the same environmental problems.

10. Convergent Evolution

11. Similar Structures for Similar Environments
Convergent Evolution
Similar Structures for Similar Environments

12. Convergent Evolution
Most evolution is Divergent (species with similar traits have a common ancestor)
According to Natural Selection, species evolve traits that help them survive in an environment.
Sometimes, the requirements to survive in an environment are so strong that several VERY DIFFERENT SPECIES evolve traits that function in similar ways. This is convergent evolution.

13. Vestigial Structures
Structures that are no longer useful, such as our appendix,, or the fingers on a whale are vestigial structures. They are evidence that these creatures evolved from other creatures that used these structures.

14. Vestigial Structures

15. Vestigial Structures

16. Other Flightless Birds with Wings
Kakapo
(New Zealand)
Kiwi
(New Zealand)
Cassowary
(New Giunea)

17. Vestigial Structures

18. Vestigial Structures

19. Vestigial Structures

20. Vestigial Human Characteristics
Spine Structure and tailbone
Body Hair and Goosebumps

21. Eyes in Blind, Cave-Dwelling Creatures

22. Selective Breeding
We humans have been selecting characteristics of pets and domesticated plants and animals for thousands of years. In many cases, we have dramatically changed how species look and behave.
In some ways, animals do this too both through sexual selection and natural selection itself.

23. Selective Breeding or Artificial Selection

24. Selective Breeding or Artificial Selection

25. Selective Breeding in Agriculture
Cows are bred for beef or milk production (Video).
Corn has been selectively bred for 600 to years by people in North America.

26. Selective Breeding

27. Animals Do Selective Breeding too! Sexual Selection
Peacock Colors
Bowerbird Nests

28. Animals Do Selective Breeding too! Sexual Selection
In many animal species, females choose males that win competitions with other males. Alleles that help them win these competitions are then selected for.

29. Animals Do Selective Breeding too! Sexual Selection
Pollinators “select” flowers that are more appealing. Bees tend to select blue and purple flowers whereas humming birds prefer red.

30. Natural Selection as a form of Selective Breeding– Just on Accident
Fishes “select” the angler fish with the most attractive lure--- by getting eaten by them!

31. Natural Selection as a form of Selective Breeding– Just on Accident
Any prey species, inadvertently selects characteristics in a predator that allows the predator to catch and eat them.

32. Fossils
There are fossils of many creatures that no longer exist today. They often show intermediate forms between species that exist today and their ancestors.
We also see that fossils deeper in the earth only show simpler creatures with more advanced life forms closer to the surface.

33. Archeoptryx

34. Archeoptryx

35. Fossils

36. Whales in the Fossil Record

37. Whale Fossils– Migration of the Blowhole

38. Whale Fossils– Migration of the Blowhole

39. Fossil Human Ancestors

40. Fossils

41. Fossils

42. Embryology
Embryos of some animals show traits that are not present in adults such as gills and tails in humans. These are evidence that these traits were found in our ancestors.

43. Embryology

44. Tail in Human Embryo

45. Hind Limb buds in Dolphin

46. DNA Similarities
If you look at the DNA of living creatures you can see the similarities.
Many sections of DNA are don’t code foe anything at all. These sections are similar to working or useful sections in other creatures.
Even in human DNA, you can see the broken parts of code that were important in an organism long ago

47. DNA Similarities

48. DNA Similarities

49. PseudoGenes
Pseudogenes are sections of chromosomes that resemble functioning genes in related creatures, but lack start codons (or promoters) and are never translate into proteins.
For example, genes for gills may be present in mammals, but in a non-functional, mutated, broken form.

50. Predictable Differences in DNA
Humans and other chimps split from dogs long before they spit from each other.
We would expect to see more genetic similarities between chimps and humans than either would have with dogs.
We would ALSO expect humans and chimps to show similar difference from chimps, and they do.

51. Evidence for Evolution
Homology
Convergent evolution
Vestigial structures
Selective Breeding
Old Earth
Embryology
Fossils
DNA