Evolution: the process by which species of living things change over a period of time.

1. Evolution:the process by which species of living things change over a period of time.

2. To scientists, a theory is a coherent explanation for a large number of facts and observations about the natural world.

3. example • Copernican theory- The sun is in the center of our solar system.

4. Evolution • The notion that species of living things slowly change as generation succeed is so well validated that it is no longer simply a theory, but a paradigm that shapes every aspect of the science of life.

5. Charles Darwin • In 1831, Charles Darwin sailed to the Galapagos Islands in the HMS Beagle. • Thirty years later he published his theory of evolution, unquestionable one of the most revolutionary ideas science has ever known. • Darwin is generally credited with the theory of evolution by natural selection.

6. Five year voyage of H.M.S. Beagle (1831-1836)

7. Darwinian fitness: ability to survive and reproduce in a particular environment

10. Darwin found many unique species on his voyage to the Galapagos • Break time

12. Natural selection • Natural selection is that the fittest survive and reproduce and therefore increase the fitness of the species.

13. Mutation = Raw material for evolutionary change

14. The story of the Giraffe

15. Natural selection • DARWIN'S FOUR POSTULATES of Natural Selection

16. Natural selection • DARWIN'S FOUR POSTULATES of Natural Selection • individuals within species vary

17. Natural selection • DARWIN'S FOUR POSTULATES of Natural Selection • individuals within species vary • some of these variations are passed on to offspring

18. Natural selection • DARWIN'S FOUR POSTULATES of Natural Selection • individuals within species vary • some of these variations are passed on to offspring • more offspring are produced than can survive

19. Natural selection • DARWIN'S FOUR POSTULATES of Natural Selection • individuals within species vary • some of these variations are passed on to offspring • more offspring are produced than can survive • individuals with the most favorable adaptations are more likely to survive and reproduce.

20. Natural Selection

22. Natural Selection

23. The Peppered Moth

24. The Peppered Moth • The peppered moth is found in England and usually lives on lichen-covered trees.

25. The Peppered Moth • The peppered moth is found in England and usually lives on lichen-covered trees. • Before the industrial revolution, there were many more light-colored moths compared to black ones. • They are both the same species, but just different colors.

26. The Peppered Moth • The peppered moth is found in England and usually lives on lichen-covered trees. • Before the industrial revolution, there were many more light-colored moths compared to black ones. • They are both the same species, but just different colors. • Light ones were well camouflaged on the lichen-covered trees, whereas the dark ones stand out.

28. Moth • During the industrial revolution, air pollution killed the lichens on the trees, resulting in bare, dark trees. • By the 1950s, the pepper moths were mostly dark colored.

29. Moth • In late 1950s a British physician and amateur moth collector, H.B.D. Kettlewell stated the HYPOTHESIS (just a guess) that the color of the moths protected them from insect-eating birds.

30. Moth • Before industrial revolution, dark-colored moths stood out against the light trees and were more likely to be eaten by birds, after industrial revolution, the reverse happened.

33. Basis for Evolution • Changes very slowly. • adaptation: a trait that increases the fitness of an individual.

34. Basis for Evolution • Changes very slowly. • adaptation: a trait that increases the fitness of an individual. • While some changes can be observed directly, much what we know about the history of life on earth comes from the fossil record.

35. Basis for Evolution • Changes very slowly. • adaptation: a trait that increases the fitness of an individual. • While some changes can be observed directly, much what we know about the history of life on earth comes from the fossil record. • A fossil-is any trace of a long-dead organism.

36. Law of Superposition • In 1669, Nicolaus Steno proposed the Law of Superposition stating that successive layers of rock or soil were deposited on top of one another by wind or water. • This means that the lowest layers are the oldest, while the top layers are the most recent. • This law is still accepted today and allows scientists to give fossils a relative age.

37. Law of Superposition

38. Geological strata (Layers of rocks) contains an evolutionary sequence of fossils

40. How we date rocks:Radioactive Dating • Uranium 238 is a naturally occurring isotope that decays to form lead. • It has a half life of 4.5 billion years. • The earth is 4.5 Billion years old. • Decay starts from the moment that uranium is incorporated into rock. • So, by measuring the relative proportion of uranium 238 and the lead that has formed we can tell how old a rock or layer of rock is.

41. Hominid Fossils

42. GRADUALISM • Living things change very slowly. GRADUALISM

43. Dino Fossil 206 million years old fossil

44. Palaeobiology

46. Maiasaura

47. All of these samples are evidence of past life

48. Carcharodon megalodon Tooth

50. PUNCTUATEDEQUILIBRIUM • Sometimes species will remain the same for a long period of time and then change very quickly. • This is usually the result of some catastrophic disaster like an earthquake or volcano.