1. Evidence of Change & How Change Occurs
Evolution:
Evidence of Change & How Change Occurs

2. Evolution - Change over time
- Process where modern organisms have descended from ancestors with modifications

3. Early Evolutionary Ideas
1. Lamarck
- among the first to explain how organisms change over time
- later disproved

4. Lamarck - relied on 2 assumptions: 1. Use and disuse
2. Inheritance of acquired traits
- both later disproved

5. 2. Charles Darwin ( )
- developed the theory of evolution by natural selection

6. - traveled around the world as a naturalist (1831-1836)

7. Galapagos wildlife

8. Darwin’s Finches & their food
Small seeds
Large seeds
Insects
Leaves

9. Evolution by Natural Selection
- Natural Selection is the result of 3 natural processes:

10. Variation in Human Height
1. Natural Variation:
- all organisms produced sexually are genetically different due to gene recombination and mutations
Variation in Human Height

11. 2. Adaptation
This natural variation or mutation may be an adaptation that helps them outcompete others to survive and reproduce.

12. Male caribou competing for mates. Gazelles struggling to reach food.
2. Competition
- resources (food, space, water) - mates
- constant struggle for existence - winners reproduce
Male caribou competing for mates.
Gazelles struggling to reach food.

13. .Natural Selection or survival of the fittest
- Those best suited will survive longer and reproduce.
- Those not suited will not survive or reproduce as often.

14. 3. Heredity
- Those that survive will pass on the very traits that helped it survive.

16. Woodpecker

17. Artificial Selection - similar to natural selection
- domestic crops and animals vary a lot

18. Artificial Selection

19. Artificial Selection
- only the best animals or plants are allowed to produce offspring

20. Artificial Selection

21. Recent Examples of Evolution

22. 1. Peppered Moths
a. Before industrial revolution, most moths were grayish and well camouflaged.

23. b. During the industrial revolution, soot stained the bark black.
- Rarer dark moths were then better camouflaged.

24. - The more common light moths were easily seen and eaten.
c. Dark moths had greater fitness and became more common.

25. 2. Resistant Diseases & Pests
a. Increased resistance to antibiotic by bacteria
b. Insects have become more resistant to pesticides

26. Resistant Pests

27. C. Speciation
- development of one species from another species

28. C. Speciation
Kaibab Squirrel
Abert Squirrel

29. 1. Process of Speciation
a. Separation of original population by a geographic barrier
b. Changed environment
c. Gene pool changes
d. Reproductive isolation
- two populations can no longer interbreed
e. New species arises

30. Speciation Single species; Same habitat Geographical barrier;
isolated populations
(c)
Genetic drift; tan vs white mice
(d)
Barrier removed; mix but don’t interbreed

31. 2. Divergent Evolution (Adaptive Radiation)
- ancestral population evolves into several different species

32. Hawaiian Honeycreepers
2. Adaptive Radiation
Hawaiian Honeycreepers

33. 2. Adaptive Radiation

34. 3. Convergent Evolution
- different organisms evolve similar adaptations to survive in similar niches
- develop analogous structures (similar function with different underlying anatomy)

35. 3. Convergent Evolution

36. 3. Convergent Evolution European Hare (lagamorph)) Patagonian “Hare”
(rodent)
Banded Wallaby
(marsupial)

37. 3. Convergent Evolution
Tasmanian “Wolf”
Coyote

38. Placentals Marsupials
Tasmanian
“Wolf”
Wolf
Ocelot
Quoll
Numbat
Anteater
Flying
Squirrel
Flying
Phalanger
Marmot
Wombat

39. 3. Convergent Evolution
American Cactus
African Euphorb

40. D. Evolutionary Theory Evolves
1. Genetic Drift
- random changes in allele frequency produce new traits

41. D. Evolutionary Theory Evolves
1. Genetic Drift
Masai Giraffe
Rothschild Giraffe
Reticulated Giraffe

42. D. Evolutionary Theory Evolves
2. Unchanged Gene Pools
- "living fossils": sharks, horseshoe crabs, coelacanth
Coelacanth
Horseshoe Crab
Chambered Nautilus

43. 3. Gradualism: 4. Punctuated Equilibrium - slow change over time
- periods of little change, followed by abrupt change

44. Gradualism Punctuated Equilibrium