Evolution, Phanerozoic Life and Mass Ex tincti ons Hilde Schwartz [email protected] Body Fossils Trace Fossils FOSSILIZED Living bone Calcium hydroxyapatite Ca10(PO4)6(OH,Cl, F, CO3)2 FilbFossil bone Fluorapatite Ca10(PO4)6(F,CO3,OH,Cl)2 EVOLUTION Descent with modification. …via tinkering with the natural genetic and phenotypic variations found in nearly all biologic populations. Wollemi pine: zero genetic variability Evidence: comparative anatomy, molecular genetics, vestigal structures, observed natural selection, and so on. Evolutionary Mechanisms Mutation Gene flow Natural selection adaptive Genetic drift random Hawaiian honeycreepers Microevolution MliMacroevolution Phanerozoic Milestones Hominids (5-(5-66 Ma) Mammal ‘explosion’ Primates Birds, Flowering plants Mammals, dinosaurs, turtles, pterosaurs, etc… Modern corals Land plant ‘explosion’ Reptiles Amphibians, giant fish, vascular plants Life on land (Plants, insects) ‘Jaws’ Vertebrates (jawless ‘fishes’) Animal ‘explosion’ Drivers of evolution Biological innovations Plate tectonics Evolvinggg global chemistry Global temperature Evolution of degradation- resistant vascular plants Berner, R. A. (2003) The long‐term carbon cycle, fossil fuels and atmospheric composition. Nature 426:323–326. Cool horse Hot horse Patterns of Phanerozoic Evolution 1.9 – 100 million species of macroorganisms Bent o n, 1985 1. Diversity has increased through time Can we trust the fossil record? Biological characteristics HbittHabitat Taphonomic processes Time The “Pull of the Recent”? Peters, 2005 Based on data in Sepkoski, 1984 (A), Niklas et al., 1983 (B), and Benton, 1985 (C,D) Number of species preserved in Lagerstatten Patterns of Phanerozoic Evolution 2. The locus of diversity has changed through Benton and Harper, 1997 time 0% of macroscopic 8585--9595% of macroscopic species are terrestrial species are terrestrial Vermeij and Grosberg, 2010 Patterns of Phanerozoic Evolution 3Etiti3. Extinction and origi iinati on rat es h ave ch anged through time ‘Background extinction’ = 2-5 families/million years families ee Extinction rates Origination rates s in marin rr illion yea mm tinctions/ xx E Raup and Sepkoski, 1982 Sepkoski, 1998 Patterns of Phanerozoic Evolution 4. Mass extinctions Rapid, global and taxonomically broad reductions in the 76% biodiversity of macroorganisms 85% 83% 80% 95% Proposed by Norman Newell (beginning in 1962) Substantiated by further quantitative analysis (e.g. Raupand SepkoskiSepkoski,, 1982) MtitihldbddMass extinctions should be regarded as mass depletions in diversity. Evolutionary Significance of Mass Extinctions Byyg removing incumbent taxa , extinction frees up ecospace for the diversification of new taxa, and thus be an agent of evolutionary change Recovery from Mass Extinctions Æ evolutionary radiations Fast or slow? 1.5 – 40 my Possible causes of mass extinctions 1. Glaciation 2. Volcanism (especially LIP eruptions) 3. Sea level change 4. Marine chemistry (anoxia/dysoxia, hypercapnia, euxinia) 5. Climate change 6. Sluggish evolution? 7. Impact 8. One-two punches? And on and on and on…….. There is no common pattern End-Cretaceous (K-T/K-Pg) 76% species extinction Schulte et al., 2010 The question: Was dinosaur eecoxtinction ggduradual or sudden? Pattern vs causation Hanna Basin Williston Basin Æ Extinction in < or= 10 ky? Why the timing (and hence the cause) of mass extinctions is difficult to ascertain: Artificial range truncations Patterns of terrestrial vertebrate survival after the K-K-PgPg boundary Counterpoint…. ‘Dracoryx hogwartsia’ and other latest Cretaceous dinosaur appear to have been over-split Some dinosaur lineages may have decreased in diversity during the last 5-10 million years of the Cretaceous The Moreno Shale, Panoche Hills How to Survive a Mass Extinction 1. Live in a range of Cretaceous bivalves habitats, across a large area Jablonski and Raup (1995) 2. Be an ecological generalist, tolerant of diverse conditions Vampyroteuthis infernalis Ceratites nodosus Brayard et al., 2009 3. Be a minimalist 4. Be lucky The Bottom Line 1. The fossil and rock records, though flawed, show real patterns of macroevolutionary change during the PhanerozoicPhanerozoic,, including at least three truly mass ive extinctions and increasing diversity through time 2. The Phanerozoic biosphere has endured multiple mass extinction events without enduring serious damage Alternative Homework Choose a mass extinction other than the K/T event to research and answer the following questions about it: 1. How long did the main extinction event last and how long did it take the biospp(phere to ‘recover’? (Expect more than one opinion.) 2. What is the favored extinction mechanism(s)? What is the evidence therefore? 3. What organ isms ‘ra diated ‘i n th e wak e of the mass extiiinction ? Your answer should not be longer than 1-2 typed pages. You should cite at least three references (not Wikipedia!) in your text and you must list your references in a ‘Citations’ section following your answers. Some References Alroy, J. (2008), Dynamics of origination and extinction in the marine fossil record, Proceedings of the National Academy of Sciences of the United States of America 105 Suppl 1:11536–11542. Alvarez, W., Asaro, F. and Montanari, A. (1990,) Iridium Profile for 10 Million Years Across the Cretaceous‐Tertiary Boundary at Gubbio (Italy), Science 250:1700‐1702 Brayard, A., Escarguel, G., Bucher, H., Monnet, C., Bruhwiler, T. (2009), Good Genes and Good Luck: Ammonoid diversity and the End‐Permian Mass Extinction, Science 325, 1118‐1121. Dahl, T.W. et al. (2010), Devonian rise in atmosphericoxygencorrelatedto the radiations of terrestrial plants and large predatory fhfish, PNAS, doi///10.1073/pnas.1011287107. Peters, S. (2004), Relative abundance of Sepkoski’s evolutionary faunas in Cambrian‐Ordovician deep subtidal environments in North America, Paleobiology, 30:543‐ 560. Raup, D.M., Sepkoski ,Jr., J.J. (1984), Periodicity of extinctions in the geologic past, Proceedings of the National Academy of Sciences of the United States of America 81(3): 801–5. Schulte, P. et al. (2010), The Chicxulub asteroid impact and mass extinction at the Cretaceous‐Paleogene boundary, Science 327:1214‐1218. Sepkoski, J.J. (1984), A kinetic model of Phanerozoic taxonomic diversity. III. Post‐Paleozoic families and mass extinctions, Paleobiology 10(2):246‐267. Sepkoski, J.J. (2002) Compendium of fossil marine animal diversity, Bulletin of American Paleontology 363:1‐560. Vermeij, G.J. and Grosberg, R.K. (2010), The great divergence: when did diversity on land exceed that in the sea?, Integrative and Comparative Biology, 1‐8, doi: 10.1093/icb/icq078.