Body Fossils Trace Fossils

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1 Evolution, Phanerozoic Life and Mass Extinctions Hilde Schwartz

2 Body Fossils Trace Fossils

3 FOSSILIZED

4 Living bone Calcium hydroxyapatite Ca 10 (PO4) 6 (OH OH,Cl,F,CO CO 3 ) 2 Fossil bone Fluorapatite Ca 10 (PO 4 ) 6 (F,CO 3, OH,Cl) 2

Wollemi pine: zero genetic variability Evidence:

6 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.

7 Evolutionary Mechanisms Mutation Gene flow Genetic drift random Natural selection adaptive Hawaiian honeycreepers

8 Microevolution Macroevolution

9 Phanerozoic Milestones Hominids (5-6 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

10 Drivers of evolution Biological innovations Plate tectonics Evolving gglobal 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: Cool horse Hot horse

11 Patterns of Phanerozoic Evolution million species of macroorganisms Benton, Diversity has increased through time

12 Can we trust the fossil record? Biological characteristics Habitat t Taphonomic processes Time

13 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

14 Patterns of Phanerozoic Evolution Benton and Harper, The locus of diversity has changed through time 0% of macroscopic species are terrestrial % % of macroscopic species are terrestrial Vermeij and Grosberg, 2010

15 Patterns of Phanerozoic Evolution 3. Extinction and origination i rates have changed through time Ex xtinctions/m million year rs in marine families Background extinction = 2-5 families/million years Extinction rates Origination rates Raup and Sepkoski, 1982 Sepkoski, 1998

76% Proposed by Norman Newell (beginning in

16 Patterns of Phanerozoic Evolution 4. Mass extinctions Rapid, global and taxonomically broad reductions in the biodiversity of macroorganisms 85% 83% 80% 95% 76% Proposed by Norman Newell (beginning in 1962) Substantiated by further quantitative analysis (e.g. Raup and and Sepkoski, 1982)

17 Mass extinctions should ldb be regarded d as mass depletions in diversity.

18 Evolutionary Significance of Mass Extinctions By removing incumbent taxa, extinction frees up ecospace for the diversification of new taxa, and thus be an agent of evolutionary change

19 Recovery from Mass Extinctions evolutionary radiations Fast or slow? my

Marine chemistry (anoxia/dysoxia, hypercapnia, euxinia) 5. Climate change 6.

20 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? 8. One-two punches? And on and on and on.. There is no common pattern

21 End-Cretaceous (K-T/K-Pg) 76% species extinction

22 Schulte et al., 2010

23 The question: Was dinosaur extinction gradual or sudden? Pattern vs causation

24 Hanna Basin Extinction in < or= 10 ky? Williston Basin

25 Why the timing (and hence the cause) of mass extinctions is difficult to ascertain: Artificial range truncations

26 Patterns of terrestrial vertebrate survival after the K-Pg boundary

27 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

28 The Moreno Shale, Panoche Hills

29 How to Survive a Mass Extinction 1. Live in a range of habitats, across a large area Cretaceous bivalves 2. Be an ecological generalist, tolerant of diverse conditions Jablonski and Raup (1995) 3. Be a minimalist Ceratites nodosus Vampyroteuthis infernalis Brayard et al., Be lucky

30 The Bottom Line 1. The fossil and rock records, though flawed, show real patterns of macroevolutionary change during the Phanerozoic, 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

31 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 biosphere to recover? (Expect more than one opinion.) 2. What is the favored extinction mechanism(s)? What is the evidence therefore? 3. What organisms radiated d in the wake of the mass extinction i? 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.

32 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: Alvarez, W., Asaro, F. and Montanari, A. (1990,) Iridium Profile for 10 Million Years Across the Cretaceous Tertiary Boundary at Gubbio (Italy), Science 250: 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, Dahl, T.W. et al. (2010), Devonian rise in atmosphericoxygencorrelatedto the radiations of terrestrial plants and large predatory fish, PNAS, doi/ /pnas / Peters, S. (2004), Relative abundance of Sepkoski s evolutionary faunas in Cambrian Ordovician deep subtidal environments in North America, Paleobiology, 30: 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): Schulte, P. et al. (2010), The Chicxulub asteroid impact and mass extinction at the Cretaceous Paleogene boundary, Science 327: Sepkoski, J.J. (1984), A kinetic model of Phanerozoic taxonomic diversity. III. Post Paleozoic families and mass extinctions, Paleobiology 10(2): Sepkoski, J.J. (2002) Compendium of fossil marine animal diversity, Bulletin of American Paleontology 363: 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: /icb/icq078

Phanerozoic Diversity and Mass Extinctions

Phanerozoic Diversity and Mass Extinctions Measuring Diversity John Phillips produced the first estimates of Phanerozoic diversity in 1860, based on the British fossil record Intuitively it seems simple