1. More on microevolution
Movie (Simpsons)

2. Evolution Evidence
Fossil: Remnant or impression of organism that lived in the past
Mostly in sedimentary rocks
Grand Canyon

3. Evolution Evidence Fossil types:
Organic: coal (reduced carbon: burns!).

4. Evolution Evidence
Fossil types:
Source energy
Coal seam

5. Evolution Evidence
Fossil types:
Thank “Lumpy Coal”.

6. Evolution Evidence
Fossil types:
Amber: fossil resin (conifer trees)

7. Evolution Evidence Fossil types:
Jurassic Park! Mosquitoes in amber to get dinosaur DNA

8. Evolution Evidence Fossil types:
Mineralize hard parts: “petrification” replaces organic molecules with rock

9. Evolution Evidence
Ex, Petrified Forest National Park, Arizona.

10. Evolution Evidence Fossil types:
Cast: Original structure dissolves but sediments retain shape
Casts of
squid-like animal
called an ammonite

11. Evolution Evidence Fossil types: Casts: footprints!.
Dinosaur footprints from Montana

12. Evolution Evidence
Principle of superposition: Old rocks lower, young rocks higher.

13. Evolution Evidence
Principle of superposition: Old rocks lower, young rocks higher.
“Relative dating”: age fossils relative to each other.

14. Evolution Evidence
Fossils show how life evolved

15. Cool fossils
Dinosaurs!
Reptiles dominated Mesozoic Era.

16. Cool fossils
Dinosaurs!
Movie stars today!.
T. rex skull

17. Cool fossils
What killed them off?
Asteroid impact.

18. Cool fossils
Crater image (buried under ocean sediment)
(Earth owee!).

19. Evolution Evidence
Radioactive dating: Decay radioactive isotopes determines time since formation

20. Evolution Evidence
Radioactive dating: Decay radioactive isotopes determines time since formation
Start 1 isotope, which gives off radioactivity and becomes another isotope (predictable rate)

21. Evolution Evidence
Radioactive dating: Decay radioactive isotopes determines time since formation
Rate measured by “half-life”: time for half original material to decay.

22. Evolution Evidence Radiocarbon dating: Radioactive Carbon-14
Half-life (5370 years): good 4 fossils < 60,000 yr old
Shroud of Turin (1988) ?

23. Evolution Evidence
Potassium-Argon dating: Radioactive Potassium forms Argon (volcanic rocks)
Half-life 1.3 billion years: good 4 fossils millions years old.

24. Relative ages converted to absolute ages (years)
Humans only in last 2 million years.

25. Evolution Evidence
“Vestigial structures”: Nonfunctional remnants of useful structures.

26. Evolution Evidence Ex, some snakes: pelvis/leg bones
Human coccyx (“tailbone”).
pelvic girdle
coccyx (bones
where many
other mammals
have a tail)
thighbone
attached to
pelvic girdle
small bone
attached to
pelvic girdle

27. Evolution Evidence
Blind cave organisms. Vestigial (nonfunctional) eyes.
Blind crayfish

28. Evolution Evidence
Blind cave organisms. Vestigial (nonfunctional) eyes.
Blind cave salamander
Blind cave fish

29. Evolution Evidence
Comparative anatomy: Same structures, modified to current use
Ex, vertebrate forelimbs

30. Evolution Evidence
Comparative embryology (embryology: study of early stages of development): Embryos related organisms go through similar stages

31. Evolution Evidence
Comparative embryology (embryology: study of early stages of development): Embryos related organisms go through similar stages
fish
reptile
bird (chicken)
mammal (human)

32. Evolution Evidence
Molecular biology: compare DNA (nucleotide sequence) or proteins (amino acid sequence)

33. Evolution Evidence
Molecular biology: compare DNA (nucleotide sequence) or proteins (amino acid sequence)
Similarity reflects relatedness.

34. Evolution Evidence Ex use: What is a quagga? Native South Africa
Extinct by 1880s (hunting)
One of 23 skins
in museums
Quagga stallion
(drawing)
Only quagga photographed
alive (in London Zoo, 1870)

35. Evolution Evidence Horse or zebra? Przewalski’s horse from Mongolia
Plains zebras
from South
Africa

36. Evolution Evidence
DNA from museum skin: quagga type of zebra

37. Evolution Evidence Experimental evidence
Natural selection: peppered moths (England)
Dark and light forms (1 gene)
Dark moth
Light moth

38. Evolution Evidence Experimental evidence
Final twist: Pollution controls changing balance again!.

39. Evolution Evidence Experimental evidence
Natural selection: Galapagos Islands

40. Evolution Evidence Experimental evidence
Natural selection: Galapagos islands
Finch species eats seeds.
Galapagos Islands : telephoto view from the space shuttle!

41. Evolution Evidence Experimental evidence
Bill size changes: food supply changes with climate.

42. Evolution Evidence Experimental evidence
Guppy experiment: guppies native to Trinidad

43. Evolution Evidence Experimental evidence Guppy experiment
Involves sexual selection: males colorful. Attractive to females but helps predators find males!

44. Evolution Evidence Experimental evidence
Experiment: Move guppies to low predator site. Male tails became larger/more colorful

45. Evolution Evidence
Artificial selection: Humans cause evolution by our activities
Intentional: Control breeding to change traits

46. Evolution Evidence Intentional: Control breeding to change traits
Ex: dog breeds.

47. Evolution Evidence
Natural selection also caused evolution of dog-like species

48. Evolution Evidence Intentional artificial selection
Ex, wild mustard now cabbage, broccoli, kohlrabi, brussel sprouts, cabbage, cauliflower, etc.
Wild
mustard
Foods you should eat more of!

49. Evolution Evidence
Artificial selection: Humans cause evolution by our activities
Unintentional: Usually species we try to kill!
“Antibiotic resistance”: bacteria evolve to be unaffected by antibiotics

50. Evolution Evidence Ex, bacterium causes tuberculosis (TB)
Some strains now resistant to most antibiotics.
Chest x-ray of TB patient
TB bacteria

51. Evolution Evidence Antibiotic resistance solutions:
Use antibiotics only when needed
Develop new antibiotics!

52. Evolution Evidence Unintentional artificial selection:
Insecticide resistance

53. Evolution Evidence Solutions: Look for new chemicals
Use “biocontrol”: natural enemies fight pest species.

54. Biocontrol Biocontrol ex: Cassava mealybug control
Cassava important crop in Africa.

55. Biocontrol
Cassava attacked by pest (mealybug)
Caused large losses.

56. Biocontrol Parasite wasp found (attacks mealybug)
Now mealybug under control.

57. Final Point
Humans: our gene pool is changing (we are evolving)

58. Final Point Human evolution
Ex: medical advances allow us to keep people with genetic disorders alive
But pass defective genes to offspring…….