1. Chapter 32 Introduction to Animal Evolution

2. What is an animal?

3. multicellular Chapter 32 Introduction to Animal Evolution What is an animal?

4. heterotrophic Chapter 32 Introduction to Animal Evolution What is an animal? multicellular

5. eukaryotes Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic

6. ingest their food Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic eukaryotes

7. no cell walls Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic eukaryotes ingest their food

8. nervous tissue Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic eukaryotes ingest their food no cell walls

9. muscle tissue Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue

10. blastula stage Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue

11. gastrula stage Chapter 32 Introduction to Animal Evolution What is an animal? multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue blastula stage

12. What is an animal? Chapter 32 Introduction to Animal Evolution multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue blastula stage gastrula stage embryonic tissue layers

13. What is an animal? Chapter 32 Introduction to Animal Evolution multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue blastula stage gastrula stage embryonic tissue layers Hox genes

14. What is an animal? Chapter 32 Introduction to Animal Evolution multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue blastula stage gastrula stage embryonic tissue layers Hox genes

15. What is an animal? Chapter 32 Introduction to Animal Evolution multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue blastula stage gastrula stage embryonic tissue layers Hox genes Animals probably evolved from a colonial, flagellated protist.

16. What is an animal? Chapter 32 Introduction to Animal Evolution multicellular heterotrophic eukaryotes ingest their food no cell walls nervous tissue muscle tissue blastula stage gastrula stage embryonic tissue layers Hox genes Animals probably evolved from a colonial, flagellated protist.

17. Chapter 32 Introduction to Animal Evolution

18. Phylogenetic trees are always being revised. Chapter 32 Introduction to Animal Evolution

19. Science is different from other ways of knowing Even our most cherished ideas in science are probationary Ideas can be falsified through experiments or observation The more testing a hypothesis withstands, the more credible it is It’s all about the evidence. Chapter 32 Introduction to Animal Evolution

20. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate

21. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues

22. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues

23. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry

24. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry

25. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity

26. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity

27. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity DeuterostomeProtostome

28. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity DeuterostomeProtostome

29. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity DeuterostomeProtostome

30. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity DeuterostomeProtostome

31. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity DeuterostomeProtostome

32. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity ProtostomeDeuterostome

33. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity ProtostomeDeuterostome

34. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity ProtostomeDeuterostome Each of the four main branches divides the tree into grades based on body plan.

35. The old system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity ProtostomeDeuterostome Molecular evidence has rearranged the branches.

36. The new system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry No body cavity Body cavity ProtostomeDeuterostome Molecular evidence has rearranged the branches.

37. The new system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry ProtostomeDeuterostome Molecular evidence has rearranged the branches.

38. The new system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry Protostome Deuterostome Molecular evidence has rearranged the branches.

39. The new system: Chapter 32 Introduction to Animal Evolution Ancestral colonial choanoflagellate No true tissues True tissues Radial symmetry Bilateral symmetry Protostome Deuterostome Molecular evidence has rearranged the branches. Lophotrochozoa (tentacles) Ecdysozoa (exoskeletons)

40. Most animal phyla originated in the “Cambrian explosion” between 525 million and 565 million years ago. Chapter 32 Introduction to Animal Evolution

41. Most animal phyla originated in the “Cambrian explosion” between 525 million and 565 million years ago. Evolution was so fast during that period that it is difficult to sort out the history. Chapter 32 Introduction to Animal Evolution

42. Causes of the Cambrian explosion: Chapter 32 Introduction to Animal Evolution

43. Causes of the Cambrian explosion: Ecological: Chapter 32 Introduction to Animal Evolution

44. Causes of the Cambrian explosion Ecological: The development of predator-prey relationships Chapter 32 Introduction to Animal Evolution

45. Causes of the Cambrian explosion Ecological: The development of predator-prey relationships Geological: Chapter 32 Introduction to Animal Evolution

46. Causes of the Cambrian explosion Ecological: The development of predator-prey relationships Geological: Increasing levels of atmospheric oxygen Chapter 32 Introduction to Animal Evolution

47. Causes of the Cambrian explosion Ecological: The development of predator-prey relationships Geological: Increasing levels of atmospheric oxygen Genetic: Chapter 32 Introduction to Animal Evolution

48. Causes of the Cambrian explosion Ecological: The development of predator-prey relationships Geological: Increasing levels of atmospheric oxygen Genetic: Changes in the Hox genes which control embryonic development. Chapter 32 Introduction to Animal Evolution

49. Three Germ Layers and the Coelom Chapter 32 Introduction to Animal Evolution

50. acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

51. Chapter 32 Introduction to Animal Evolution acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

52. Chapter 32 Introduction to Animal Evolution acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

53. Chapter 32 Introduction to Animal Evolution acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

54. Chapter 32 Introduction to Animal Evolution acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

55. Chapter 32 Introduction to Animal Evolution ectoderm mesoderm endoderm acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

56. Chapter 32 Introduction to Animal Evolution ectoderm mesoderm endoderm acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome

57. Chapter 32 Introduction to Animal Evolution ectoderm mesoderm endoderm acoelomate coelomate protostome pseudocoelomate coelomate deuterotostome mouth anus mouth

58. Chapter 32 Introduction to Animal Evolution