Mass Extinction!

1. Mass Extinction! “There are millions of different species of animals and plants on earth—possibly as many as forty million. But somewhere between five and fifty billion species have existed at one time or another. Thus, only about one in a thousand species is still alive—a truly lousy survival record: 99.9% failure!” ~David Raup Presented by: Livia Montone (montone@marine.rutgers.edu)

2. How do you define “Mass Extinction”? • Any substantial increase in the amount of extinction (ie. lineage termination) suffered by more than one geographically widespread higher taxon during a relatively short interval of geologic time, resulting in at least temporary decline of standing diversity. (from Sepkoski, 1986)

3. How do you define “Mass Extinction”? • Any substantial increase in the amount of extinction(ie. lineage termination) suffered by more than one geographically widespread higher taxonduring a relatively short interval of geologic time, resulting in at least temporary decline of standing diversity. (from Sepkoski, 1986) • An extinction of a significant portion of the world’s biota in a geologically insignificant period of time. (from Hallam and Wignall, 2000)

4. Outline • Geologic Time Scale • Background and mass extinctions • Phases of extinction • Biological causes of extinction • Physical causes of extinction • Geochemical Toolbox • The Big Five

8. A side note about time units vs. rock units… Time Units (ie. periods of time) • Eon • Era • Period • Epoch • Age • Rock Units (ie. sequence of rocks) • Eonothem • Erathem • System • Series • Stage

10. Phases of Mass Extinction

12. Biological Causes of Extinction • Minimum Viable Population and the Problems of small populations • Demographic Stochastity • Genetic Deterioration • Social Dysfunction • Extrinsic Forces

13. GAMBLER’S RUIN!

14. GAMBLER’S RUIN Results

15. GAMBLER’S RUIN Results $10 Trial 2 $10 Trial 4 $10 Trial 5

16. GAMBLER’S RUIN Results $5 Trial 2 $5 Trial 3 $5 Trial 4

17. Survivorship Curve

18. Proposed Physical Causes of Extinction Mass Extinctions • Global climate change • Global sea level change • Change is salinity of ocean • Anoxia • Volcanism • Extraterrestrial Impact Background extinction • Regional climate change • Regional sea level change

19. Geochemical Toolbox • Carbon isotopes • Oxygen isotopes • Strontium isotopes • Iridium and platinum group elements

20. Carbon isotopes • Typically reported as 𝜹13C where: 𝜹13C= • Marine biomass 𝜹13C= -25 ‰ • Oceanic carbonates 𝜹13C= -0.5 to 1‰ • Increase organic matter burial, 𝜹13Ccarb goes up • Decrease organic matter burial, 𝜹13Ccarb goes down • Ocean anoxic event= + change in 𝜹13Ccarb

21. Oxygen isotopes • Typically reported as 𝜹18O where: 𝜹18O = • Positive 𝜹18Ocarb values indicate colder climate • Negative 𝜹18Ocarb values indicate warmer climate

22. Strontium isotopes • Ratio of 87Sr to 86Sr is the result of: • Continental weathering processes • Interaction of seawater with basalt at mid-ocean ridges • Marine carbonates correspond to seawater values

23. Iridium and Platinum Group Elements • Increased Iridium (several ppb) as an indicator of bolide impact • Increased Ir with appropriate ratios to Platinum, Gold, and Asmium

24. The Big Five • Paleogeography • Pre-extinction Taxa • Big Losers • Geologic and Fossil Record • Possible Causes • Geochemical Reconstructions

25. Ordovician Mass Extinction

26. Ordovician Mass Extinction

27. Ordovician Invertebrate Fossils Ordovician Mass Extinction

28. Ordovician Mass Extinction

29. What went extinct in the Ordovician? • 57% of genera; >25% of families • Graptolites, conodonts, nautiloids, plankton, brachiopods, trilobites, ostracods, bryozoans, echinoderms, bivalves, rugose and tabulate corals, stromatoporoids… Ordovician Mass Extinction

30. Ordovician Mass Extinction

31. O-S GSSP Location- Dob’s Linn, Scotland • Other well-studied locations on Anticosti Island, Quebec Ordovician Mass Extinction

32. Causes of Ordovician Mass Extinction • Glacial episode beginning in Mid-O • Sea level regression • Global cooling Ordovician Mass Extinction

33. Stable Isotope Data Ordovician Mass Extinction

34. The End-Devonian Mass Extinction Devonian Mass Extinction

35. Devonian Mass Extinction

36. Devonian Mass Extinction

37. Selectivity of End-Devonian Mass Extinction • Kellwasser (Frasnian-Famennian) • Preferential loss of warm-water taxa • Loss of shallow-water taxa • Loses among some pelagic groups • Hangenberg (Devonian-Carboniferous) • Most severe extinction in water column • Less in benthos Devonian Mass Extinction

38. Geochemical Signals • Carbon-isotopes • Ambiguous records • Oxygen-isotopes • Equally as confusing • Ir and trace metals • Enriched in Ni and V Devonian Mass Extinction

39. Causes of End-Devonian Mass Extinction • Bolide impact • Anoxia • Cooling? • Warming? • Brackish oceans Devonian Mass Extinction

40. Paleozoic “nemesis”The End-Permian Mass Extinction Permian Mass Extinction

43. Geochemical Signals

45. Causes of End-Permian Mass Extinction • Cosmic Radiation • Brackish Oceans • Regression • Bolide Impact • Cooling? Warming? • Hypercania • Volcanic Winter • Global Marine Anoxia

48. End-Triassic Mass Extinction • Not well-studied • In marine realm- 48% extinction of invertebrate genera • Cephalopods • Bivalves • Gastropods • Brachiopods • Continental realm • Plants less affected than marine • Tetrapod turnover

49. Geochemical Signals

50. Causes of End-Permian Mass Extinction • Climate Change • Volcanism ? • Bolide Impact • Sea level Change • Anoxia