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Evidence for evolution: Fossils

Evidence for evolution: Fossils. John Murray. Evidence for evolution: Fossils. As told by a series of & papers. Fossils. Oxford Dictionary: “ the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form ”

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Evidence for evolution: Fossils

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  1. Evidence for evolution: Fossils John Murray

  2. Evidence for evolution: Fossils As told by a series of & papers

  3. Fossils Oxford Dictionary: “the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form” ”a person or thing that is outdated or resistant to change”

  4. Fossils Usually formed from hardest, most resistant parts of organisms (but not always) Sedimentary rocks  Fossil record is incomplete

  5. Fossils (1) OrganismicIncompleteness Fossil record is incomplete

  6. Fossils (2) StratigraphicIncompleteness Effect of varying rates of deposition on apparent rates of change in the fossil record. The numbers refer to equal lengths of time. Fossil record is incomplete

  7. Fossils (3) EcologicalIncompleteness Fossil record is incomplete

  8. 49Ma: Grube Messel

  9. Fossils Tangible evidence for evolution (Palaeo) ecology & ethology Evolutionary rates History of Life So why bother at all with fossils? Fossil record is incomplete

  10. 150Ma: Solnhofen A snapshot Tangible evidence for evolution

  11. Caudipteryx zoui

  12. (Palaeo)ecology & ethology

  13. 1859: Darwin’s Origin of Species Evolutionary rates

  14. time morphology Darwinian view: ‘Classical’ Phyletic gradualism

  15. time morphology • Key points: • Evolutionary rates remain constant through speciation event. • Small changes seen gradually through generations. • Darwin’s ‘Paradigm’

  16. 1970s: Eldredge & Gould: Punctuated Equilibrium

  17. time morphology • Key points: • Evolutionary rate very low (0) over long periods • Speciation in short periods of time with rapid rates of change. • Eldridge & Gould argued that this model most closely resembles the evidence from fossil record. Punctuated Equilibrium

  18. Vs Punctuated Equilibrium Phyletic Gradualism Debate about which model is more appropriate has continued to present

  19. Peter Sheldon 15,000 trilobites!

  20. History of Life History of Earth

  21. Base of Palaeogene

  22. Terrestrialisation

  23. Zachelmie trackway

  24. Evolution & the tree of life (the state of the art)

  25. Phylogenetic tree: Lancelet (outgroup) Lamprey Bass Vertebral column Frog Fossils? Hinged jaws Turtle Four walking legs Amnion Leopard Time? Hair

  26. Stem Group Crown Group

  27. Origin of major animal groups (Phyla) (Stem – Crown groups get really tricky here!)

  28. Erwin et al. Science334, 1091-7 (2011)

  29. History of Life Fig. 3. Detailed stage-level depiction of the animal fossil record as compared to the molecular divergence estimates for 13 different animal lineages. Shown in thick black lines are the known fossil records of each of these 13 lineages through the Cryogenian-Ordovician; most lineages make their first appearance in the Cambrian, consistent with the known fossil record of all animals. Further, the extent of these stratigraphic ranges closely mirrors the molecular estimates for the age of each of the respective crown groups (red colored circles), highlighting the general accuracy of the molecular clock. Only cnidarians have an unexpectedly deep crown-group origination as estimated by the molecular clock, as the deep demosponge divergence is apparent from taxon-specific biomarkers (gray bar). Erwin et al. Science334, 1091-7 (2011)

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