1. Evolution
Chapter 16.1, 16.2, and 16.3

2. Overall Theme of Evolution
Evolution Requires 3 elements:
1. Variety
2. Selection
3. Time

3. Variety
For evolution to occur, there must be ways for organisms within a species to be different from each other
Variety is generated through mutations and sexual reproduction

4. Evolution is now considered a Theory
What is the difference between a Theory and a Hypothesis?
Theory- a hypothesis that has been confirmed by testing and has much evidence backing it up
Hypothesis- an educated guess that can be tested

5. Charles Darwin
Charles Darwin took many years to publish his theory of evolution by natural selection.
Many of his ideas were first inspired by his 1831 global voyage on the ship called the Beagle.

6. Charles Darwin (1809 – 1882)
In l831, when Darwin was only 22 he signed on as the ship’s naturalist aboard the Beagle on a 5-year expedition around the world.
Darwin studied and collected many different and unusual specimens which contributed to his theory.

7. Darwin’s Voyage to the Galapagos Islands
Some of Darwin’s most important observations were made on the Galapagos Islands.

8. Animals of the Galapagos Islands
                                                                    Blue Footed Boobies in the Galapagos
Animals of the Galapagos Islands

9. Galapagos Islands: Finches
Darwin observed organisms with slight differences.
Example: Galápagos finches with different beaks

10. Assumptions At That Time
Species were fixed creations that never changed and they were arranged from least complex to most complex.
Earth is only a few thousand years old.

11. Darwin’s Book: On the Origin of Species
Darwin’s book stated:
Species change
Species evolved from a common ancestor over time (implying a much older Earth)
Natural Selection is the mechanism for change

12. The only picture in Darwin’s book shows Common Ancestry

13. Who influenced Darwin’s Ideas?
Jean Baptiste Lamarck (Biology)
Thomas Malthus (Economics)
Charles Lyell (Geology)

14. Jean Baptiste Lamarck
Lamarck proposed that organisms change over time as they adapt to changing environments.

15. Jean Baptiste Lamarck
He also incorrectly proposed that changes due to use and disuse of a characteristic would be passed on to offspring.
Example: A baseball player’s children would inherit strong arm muscles
Giraffe’s neck stretches
to reach food

16. Charles Lyell Lyell studied fossils and rock layers
His work showed that Earth’s history was long enough for species to have evolved gradually.

17. Charles Lyell Lyell found evidence of long extinct habitats
Example: Fossil sea shells in the Andes Mountains

18. Thomas Malthus
Malthus observed that human populations were increasing faster than the food supply.
Darwin saw that all kinds of organisms tend to produce more offspring than can survive.

19. Darwin’s Theory of Natural Selection
Overproduction- Organisms produce more offspring than can survive. Leads to competition for resources.
Variety- Variation exists within every population.
Selection- Having a particular trait can make individuals more or less likely to survive and reproduce offspring
4) Adaptation– Over time, the traits that improve survival and reproduction become more common.

20. Artificial Selection
A human practice of breeding animals or plants that have desired traits
Example: Pigeon and Dog breeders

21. Artificial Selection

22. Evidence for Evolutionary Theory
Galapagos Finches
Transitional Fossils
Biogeography
Embryology
Homologous Structures
Biochemistry

23. Galapagos Finches
All Galapagos finch species are similar to each other.
Beak size and shape are different due to different types of food.

24. Transitional Fossils Traces of organisms that lived in the past.
Some fossils show a pattern of gradual change from the past to the present

25. Transitional Fossils Tiktaalik roseae (Amphibian/Fish)
Fossils dated 375 million years old

26. Transitional Fossils Archaeopteryx lithographica (Bird/Reptile)
Fossils dated 150 million years old

27. Transitional Fossils Ambulocetus natans called the “walking whale”
Fossils dated ~ 50 million years old

28. Transitional Fossils
Rodhocetus kasrani-extinct whale with mammal characteristics
Fossils dated ~ 46 million years old

29. Transitional Fossils Basillosaurus cetoides-marine mammal
Fossils dated ~ 40 million years old

30. Physeter macrocephalus Modern sperm whale
Transitional Fossils
Physeter macrocephalus Modern sperm whale

31. Fossils: Common Ancestry
Darwin found fossils of Giant extinct Armadillos in South America that are related to Modern day Armadillos.

32. Biogeography Study of the locations of organisms around the world.
Example: The Rhea, Ostrich, and Emu are similar in size, shape, eating habits, and habitat. However each species lives on a separate continent. (Convergent Evolution)

33. Biogeography
Rhea (South America)
Ostrich (Africa)
Emu (Australia)

34. Study of the first stage of development
Embryology
Study of the first stage of development

35. Homologous Structures
Characteristics that are similar in structure but different in function
Homo = Same
Same evolutionary history

36. Homologous Structures

37. Biochemistry Comparison of DNA or amino acid sequences over time
This is the most powerful evidence for a common ancestor

38. Biochemistry The following is a comparison of genes in Humans and Monkeys

39. Common Cell Processes
Cellular Respiration pathways are similar processes in most species
Mitosis process is the same in all eukaryotes

40. Vestigial Structures
Structures that have lost all or most of their original function in a species through evolution
Examples: Mole rat eyes, Manatee fingers, Human wisdom teeth, Whale leg bone, Human Appendix

41. Vestigial Structures

42. Adaptations
An inherited trait that is present in a population because the trait helps individuals survive and reproduce in their environment.

43. Adaptations
Inuit people, who live in the extreme cold of the Arctic, have short, stout bodies that conserve heat.

44. Adaptations
Masai people, who live in the arid lands of eastern Africa, have tall, lean bodies that disperse heat well.

45. Adaptations Venus Fly Trap
Lives in poor soil and acquires nutrients such as Phosphorus from insects
Remember that
Phosphorus is
needed for DNA

46. Adaptations
Succulents have thick leaves that store water to prevent drying out

47. Adaptations
Camouflage- blend in with the environment

48. Adaptations

49. Adaptations Mimicry- mimics or copies characteristics of others
Fly vs Honey Bee Moth vs Bracket Fungi

50. Adaptations
King snake vs coral snake Moth Eye Spot vs Owl Eyes Remember: Red touch Yellow, Kill a Fellow; Red touch Black, Good for Jack

51. Does Natural Selection Occur Now?
Yes, Bacteria reproduce very quickly
Over decades of antibiotic use, bacteria have developed resistance to antibiotic medicines
Mutations for antibiotic resistance arise naturally and often in bacteria

52. Antibiotic Resistance
Today, nearly all bacteria are becoming resistant to one or more antibiotics
As bacteria become resistant, physicians must switch to using different antibiotics.
Example: Staph infections and Tuberculosis are both more difficult to treat

53. Misconceptions of Evolution
Evolution does not just add complexity, it can take it away as well
Example: A Tapeworm lacks many organ systems

54. Misconceptions of Evolution
Evolution does not “finish” with a “perfect trait”
The human eye has a blind spot due to the Optic Nerve

55. Evolution Can Add Complexity
Random mutation can lead to more complex changes
Example: The icefish is able to withstand the Antarctic freeze because it has an antifreeze protein in its blood that was mutated from the typsinogen protein.

56. 2 Subgroups of Evolution
Microevolution- refers to evolution as a change in allele frequency in populations
Macroevolution- refers to the appearance of a new species over time
The following slides are examples of Macroevolution

57. Divergent Convergent Evolution Evolution
See Page 383, Figure 8
new organisms
some similarities begin to develop in same environment
common ancestor
different ancestries

58. Adaptive Radiation or Divergent Evolution
Adaptive Radiation is a special case of divergent evolution - when many niches are filled
Notice that there are 14 species that evolved from the original Finch from South America

59. Gradualism vs. Punctuated Equilibrium
Slow, even change
Long periods of no change with bursts of rapid change

60. Coevolution
Populations are not isolated, and often evolve in response to each other
Coevolution is when 2 species are competing to “one up” each other with adaptations

61. Coevolution
This moth species and this orchid species have coevolved is a close relationship. The moth feeds exclusively on the orchid, and the orchid’s pollen is spread by the moth.

62. Another View of the Moth and Orchid

63. The End