Chapter 15

1. Chapter 15 Theory of Evolution

2. 15-1 • History of Evolutionary Thought

3. In the 1800’s scientists began to present evidence that the species on Earth have changed over time, and that the earth was much older than previously thought

4. Scientists had begun to study the strata or rock layers lower strata formed first and are therefore older

6. Georges Cuvier (1769-1832) • -began reconstructing organisms from fossil bones • -found many unique species and different organisms in different layers • -he contributed to the acceptance of geologic change and extinction.

10. Charles Lyell (1797-1875) • -Wrote “Principles of Geology” • -stated that the process that formed the Earth continue to occur.

11. Jean Baptiste Lamarck (1744-1829) • -supported the idea of evolution, he stated: • A) populations of organisms change over time (correct) • B) acquired traits were passed on to offspring (incorrect)

12. Acquired traits • -a trait that in not determined by genes- it arises during the organism’s lifetime • -only genetic traits can be passed on.

13. Charles Darwin (1809-1882) • 1830’s a 5 year journey to South America • He studied organisms in S. America and the Galapagos Islands

14. Chapter 15 Darwin’s Voyage

15. Read Lyell’s “Principles of geology”- it made Darwin realize that geologic time is very slow, so modifications in the environment might also be very slow. • He developed the idea of Natural Selection. Darwin and Alfred Wallace presented their hypothesis at the same time. But Darwin’s “Origin of Species” was published first.

16. Darwin Proposed • A) descent with modification • B) Modification by natural selection

17. Descent with Modification • Newer organisms are modified descendents of older species (ex. Galapagos tortoises)

19. Modification by Natural Selection P. 300 • 1) Overpopulation- species produce too many offspring. (Darwin used Thomas Malthus’s ideas on human population. The idea of competition among organisms) • 2)genetic Variation- within a species, individuals have different traits or variations.

20. 3)Struggle to Survive- those organisms that are best suited to their environments will survive. • 4) Differential reproduction- those with the best adaptations survive and reproduce (pass on their traits)

21. Chapter 15 Natural Selection

22. “Fitness”- ability to adapt, survive and reproduce

23. A favorable trait gives the organisms an adaptive advantage.

24. 15-2 • The fossil record

25. Fossils • Traces of long dead organisms, often form in sedimentary rock. • molds, casts, tracks, amber...

26. Superposition • Lower layers (strata) are the oldest

27. Relative Age • Age compared to other fossils c b a

28. Absolute Age • Age in years. Can be done by radiometric dating of the rock. The age is inferred from the age of the rock.

29. The fossil record is not complete • Not all organisms form fossils • Fossils can only form under certain conditions • Not all fossils have been found by humans

30. From the fossil record scientists can infer: • 1. organisms lived at different times • 2. today’s organisms are different from those of the past (ex. Trilobites) • 3. fossils found in adjacent layers are more alike than those found in layers farther apart • 4. when and where organisms existed (they compare fossils from around the world)

31. Transitional species P. 304 • Organisms that have features between a hypothesized ancestor and a later species. • Some groups of organisms have many transitional species that have been discovered (whale, horse) others do not.

32. Chapter 15 Evidence of Whale Evolution

35. Biogeography • Study of geographical distributions of fossils and living organisms. Living organisms are in areas where their ancestors lived.

36. The study of anatomy and embryology support the idea of descent with modification.

37. Homologous Structure P. 305 • Similar structures that are found in a common ancestor--showed species shared an ancestor. • Ex. Human arm, bird wing, dog leg

39. Analogous Structures • Structures that serve the same purpose, but have a different evolutionary development. • Ex. Bat wing and butterfly wing

40. Vestigial structures • Structures that seem to serve no useful purpose. Part of our evolutionary history. • Ex. Human appendix, human tail bone, whale pelvis

41. Embryology P. 306 • Early stages of vertebrates appear very similar • Can infer that vertebrates share a common ancestor

42. Similar macromolecules • Similar DNA, RNA, and amino acid sequence between closely related organisms

43. Chapter 15 Hemoglobin Comparison

44. Scientists use many types of evidence to form, challenge and refine the hypothesis and theories about evolution. • Ex. Developing a phylogenic diagram P. 307

45. Chapter 15 Evolutionary Relationships Between Whales and Hoofed Mammals

46. 15-3 • Evolution in Action

47. Evolution is a continuing process. • Ex. Anole lizards p. 308-309

48. Convergent evolution • The environment selects similar phenotypes, even though the ancestors were different • ex. Body shape of dolphins and sharks

50. Divergent Evolution • Two or more related pop. or species become more dissimilar. • Usually due to different habitats (adaptive radiation) or human intervention (artificial selection)