Evolution in the Fossil Record: A Case Study of Graptolites

Transcript

1. Evolution in the Fossil Record Alex Clarke A Case Study

   of Graptolites Monday, 27 February 12

2. What is the Fossil Record The totality of fossilised artefacts

   and their placement within the earth’s rock strata. It provides information about the history of life on earth, for instance what the organisms look like, where and when they live, how they evolved, etc. Fossil record can provide interesting information about the evolution and the history of life on earth such as the way the particular species have lived during a specific geological period and then evolved in time. — Biology Online Monday, 27 February 12

3. Why we Use the Fossil Record • To look millions

   of years back in time Monday, 27 February 12

4. Why we Use the Fossil Record • To look millions

   of years back in time • To see organisms evolving through time Monday, 27 February 12

5. Why we Use the Fossil Record • To look millions

   of years back in time • To see organisms evolving through time • To learn about the Earth in the past Monday, 27 February 12

6. Why we Use the Fossil Record • To look millions

   of years back in time • To see organisms evolving through time • To learn about the Earth in the past • To predict what the Earth will be like in the future Monday, 27 February 12

7. Problems with the Fossil Record • Preservation is extremely unlikely

   Monday, 27 February 12

8. Problems with the Fossil Record • Preservation is extremely unlikely

   • Certain environments are better for preservation than others Monday, 27 February 12

9. Problems with the Fossil Record • Preservation is extremely unlikely

   • Certain environments are better for preservation than others • Usually only get hard-parts preserved Monday, 27 February 12

10. — microecos.wordpress.com Monday, 27 February 12

11. Problems with the Fossil Record • Can only see ~600

    Million Years • Preservation is extremely unlikely • Certain environments are better for preservation than others • Usually only get hard-parts preserved Monday, 27 February 12

12. Problems with the Fossil Record • Can only see ~600

    Million Years • Difficult to determine relatedness • Preservation is extremely unlikely • Certain environments are better for preservation than others • Usually only get hard-parts preserved Monday, 27 February 12

13. A fundamental category of taxonomic classification, ranking below a genus

    or subgenus and consisting of related organisms capable of interbreeding. Species vs Morphospecies Species Morphospecies A typological species distinguished solely on the basis of morphology. — The Free Dictionary Monday, 27 February 12

14. What is a Graptolite? Monday, 27 February 12

15. — Jan Zalasiewicz Monday, 27 February 12

16. Monday, 27 February 12

17. Stipe Thecae Monday, 27 February 12

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19. Metazoa (Animalia) Eumetazoa Bilateria Deuterostomia Hemichordata Graptolithina Monday, 27 February

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20. Monday, 27 February 12

21. Metazoa (Animalia) Eumetazoa Bilateria Deuterostomia Hemichordata Graptolithina Monday, 27 February

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22. 542 Ma 488 Ma Cambrian First Graptolites Monday, 27 February

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23. Monday, 27 February 12

24. 488 Ma Cambrian Ordovician Dendroid Graptolites Detach from Sea Floor

    Monday, 27 February 12

25. — fossilmall.com Monday, 27 February 12

26. 488 Ma mbrian 444 Ordovician Reduction in Stipe Number Monday,

    27 February 12

27. Monday, 27 February 12

28. 488 Ma an 444 Ma Ordovician Greater reduction in Stipe

    Number Monday, 27 February 12

29. Monday, 27 February 12

30. 488 Ma 444 Ma Ordovician Stipes open up Monday, 27

    February 12

31. Monday, 27 February 12

32. 488 Ma 444 Ma Ordovician Direction of Growth Changes Monday,

    27 February 12

33. Monday, 27 February 12

34. 488 Ma 444 Ma Ordovician S Stipes start to fuse

    Monday, 27 February 12

35. Monday, 27 February 12

36. 488 Ma 444 Ma Ordovician Siluri Graptolite becomes a single

    stipe with thecae on both sides Monday, 27 February 12

37. Monday, 27 February 12

38. 444 Ma Ordovician 41 Silurian Stipes develop thecae on only

    one side Monday, 27 February 12

39. Monday, 27 February 12

40. Graptolites Go Extinct 416 Ma Silurian Devonian 359 M Monday,

    27 February 12

41. What Does This Matter? Monday, 27 February 12

42. Monday, 27 February 12

43. Jan Zalasiewicz (cue Agata to correct my pronunciation) Monday, 27

    February 12

44. What Does This Matter? Monday, 27 February 12