Who is credited with theory of natural selection?

1. Who is credited with theory of natural selection? Charles Darwin

2. What organisms did Darwin study in his investigation of evolution?

3. Mutation A change in a DNA sequence, usually occurring because of errors in replication or repair. Mutation is the ultimate source of genetic variation.

4. Gene Flow (Migration) The chance of an individual migrating to another population and sharing it’s genes there.

5. Genetic Drift • The drift over time of allele frequencies in a population due to random sampling effects forming successive generations.

6. Natural Selection A process of evolution in which traits that result in better fitness of an individual survives to the next generation.

7. The process by which organisms choose their mates based on advantageous traits that will be carried to the next generation. Non-random mating or “Sexual Selection”

8. Why is this statement FALSE????????? Evolution is the idea in which an individual changes over large amounts of time. Evolution is the idea in which POPULATIONS change over large amounts of time.

9. Evolution Evolution

10. Over a great period of time evolution can result in the formation of a new species. This is called? Speciation

11. I. What is Evolution? • A theory stating that things change over time. • In Science, evolution refers to the process in which organisms produce offspring which are biologically different than their ancestors, yet are more capable of surviving and producing offspring in the environment.

12. B. Theory- A theory, in science, is a widely accepted set of explanations of observations and phenomena.

13. Theories • 1. Are more than an educated guess • 2. Can never be proven, only disproved. • 3. Have evidence that support it. • 4. Become more widely accepted with more evidence supporting them.

14. What is it? • A theory stating that things change over time. • In Science, evolution refers to the process in which organisms produce offspring which are biologically different than their ancestors, yet are more capable of surviving and producing offspring in the environment.

16. Evolution • Charles Darwin – credited with the theory of evolution • In 1859 The Origin of Species by Means of Natural Selection. • Major Idea of his work: Organisms living today have been produced through a long slow process called evolution

17. Figure 15–1 Darwin’s Voyage Section 15-1

19. Giant Tortoises of the Galápagos Islands Section 15-1 Shape of Shell Corresponds to different habitats Pinta Tower Marchena Pinta IslandIntermediate shell James Fernandina Santa Cruz Isabela Santa Fe Hood Island Saddle-backed shell Floreana Hood Isabela Island Dome-shaped shell

20. Mastadon Pterosaur

21. Brittle Star T-Rex

22. Evidence of Evolution • 1. Paleontology- study of extinct life • Fossils- most found in sedimentary rock where bone has been replaced by minerals. (Fossils found in tar, amber, or ice may be better preserved) • Provides evidence about the history of life • Shows how organisms have changed over time • Fossil record is incomplete because most organisms die without leaving any trace! • Shows that there were several mass extinctions

23. Dating Fossils • Radioactive (absolute dating): Some radioactive elements breakdown over time at a known, steady rate. Each radioactive element has a different half life. • Ex: U-238 has a half life of 4.5 billion years • C-14 has a half life of 5,770 years

25. IV. Dating Fossils • Radioactive (absolute dating): Some radioactive elements breakdown over time at a known, steady rate. Each radioactive element has a different half life. • Ex: U-238 has a half life of 4.5 billion years • C-14 has a half life of 5,770 years • Relative dating: Lower layers of rock are usually older than the layers above. Can be less accurate than radioactive methods due to erosion, faulting from earthquakes, etc.

27. Sediment Layers

28. Younger Older Relative Dating

29. You can tell about the history of the land by looking at layers of the Earth. How has this environment changed over the years?

30. IV. Dating Fossils • (Using data collected from rock samples from the Earth, moon, and meteorites, most scientists agree that the Earth is about 4.6 billion years old)

31. Age of fossil with respect to another rock or fossil (that is, older or younger) Age of a fossil in years Comparing depth of fossil in the layers of rock to the position of a reference fossil or rock Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen Not a precise age (only a comparison) Difficulty of radioassay laboratory methods Compare/Contrast Table Section 17-1 Comparing Relative and Absolute Dating of Fossils Relative Dating Absolute Dating Can determine Is performed by Drawbacks Go to Section:

32. 1. Fossils of animals the size of goats were dated at 5 million years old. Similarly, fossils of larger animals were dated at 3 million years old. Both animals were similar in body structure to today's horses. Using this data, which inference can scientists make? A. The animals were probably ancestors of today’s horses B. The animals had no relationship to one another. C. Today's horses and these animals probably lived together at some time in the past. D. Today's horses are faster than these animals were.

33. 1. Fossils of animals the size of goats were dated at 5 million years old. Similarly, fossils of larger animals were dated at 3 million years old. Both animals were similar in body structure to today's horses. Using these data, which inference can scientists make? A. The animals were probably ancestors of today’s horses B. The animals had no relationship to one another. C. Today's horses and these animals probably lived together at some time in the past. D. Today's horses are faster than these animals were.

34. 2. Geographic Distribution- unrelated species now living on different continents, under similar ecological conditions evolve certain striking features in common. • A.     Suggests that different organisms living in similar • environments could evolve similar traits • B.     North American muskrat and the South American • coypu • C.   Beaver in North America and capybara in South • America

36. Figure 15–14 Geographic Distributionof Living Species Section 15-3 Beaver Beaver Muskrat Beaver andMuskrat Coypu Capybara Coypu andCapybara NORTH AMERICA Muskrat Capybara SOUTH AMERICA Coypu

37. Evidence (8): Geography Marsupials • Geographic spread of • organisms also tells of • their past evolution. • Marsupials occur in • two populations today • in the Americas and • Australia. • This shows the group • evolved before the • continents drifted apart evolution.berkeley.edu/evosite/lines/IVCexperiments.shtml en.wikipedia.org/wiki/Image:Kangaroo_and_joey03.jpg

38. 3. Embryology- study of organisms at an early stage of development • Similarities in the development of many organisms suggest anevolutionary relationship (common ancestor).

40. 4. Homologous Structures- body parts of different • organisms that have the same basic structure. • Develop from the same embryonic tissues but have different mature forms • Similarities in body parts suggest a common ancestor • Ex: whale flipper and a human hand

42. Figure 15–15 Homologous Body Structures Section 15-3 Turtle Alligator Bird Mammals Typical primitive fish

43. 5. Vestigial Structures- body parts that are reduced in size and have no function • Suggests that as body part was no longer needed in environment they were lost • Ex: human appendix or hip and leg bones in snakes

45. Vestigial Structures • As evolution progresses, some • structures get side-lined as they • are not longer of use. These • are known as vestigial structures. • The coccyx is a much reduced • version of an ancestral tail, which • was formerly adapted to aid • balance and climbing. • Another vestigial structure in • humans is the appendix. The coccyx is a vestigial tail en.wikipedia.org/wiki/Image:Illu_vertebral_column.jpg

46. 6. Artificial Selection- Because of natural variation, breeders are able to produce a wide range of plants and animals that look very different from their ancestors • Natural Variation- Differences among individuals of the same species (ex: no 2 human beings look exactly like unless they are identical twins) • Variations – due to mutations (changes in a gene). Remember not all mutations are harmful!

50. Biochemistry- All organisms share similar biochemistry • All organisms have DNA & RNA • All organisms use ATP as cellular energy • Many organisms use many of the same hormones • Ex: Prolactin- milk production in mammals