NJU Course Extinctions: Past, Present & Future Prof. Norman MacLeod School of Earth Sciences & Engineering, Nanjing University Extinctions: Past, Present & Future Extinctions: Past, Present & Future Course Syllabus (Revised) Section Week Title Introduction 1 Course Introduction, Intro. To Extinction Introduction 2 History of Extinction Studies Introduction 3 Evolution, Fossils, Time & Extinction Precambrian Extinctions 4 Origin of Life & Precambrian Extionctions Paleozoic Extinctions 5 Early Paleozoic World & Extinctions Paleozoic Extinctions 6 Middle Paleozoic World & Extinctions Paleozoic Extinctions 7 Late Paleozoic World & Extinctions Assessment 8 Mid-Term Examination Mesozoic Extinctions 9 Triassic-Jurassic World & Extinctions Mesozoic Extinctions 10 Labor Day Holiday Cenozoic Extinctions 11 Cretaceous World & Extinctions Cenozoic Extinctions 12 Paleogene World & Extinctions Cenozoic Extinctions 13 Neogene World & Extinctions Modern Extinctions 14 Quaternary World & Extinctions Modern Extinctions 15 Modern World: Floras, Faunas & Environment Modern Extinctions 16 Modern World: Habitats & Organisms Assessment 17 Final Examination Early Paleozoic World, Life & Extinctions Norman MacLeod School of Earth Sciences & Engineering, Nanjing University Early Paleozoic World, Life & Extinctions Objectives Understand the structure of the early Paleozoic world in terms of timescales, geography, environ- ments, and organisms. Understand the structure of early Paleozoic extinction events. Understand the major Paleozoic extinction drivers. Understand the degree to which these correlate with Paleozoic extinction events. Early Paleozoic World, Life & Extinctions Presentation Topics Stratigraphy - chronostrati- graphy & geochronology Geography - tectonics & distri- bution Climate - circulation, tempera- ture, weather Biota - protists, invertebrates, vertebrates, plants Evolution - evolutionary faunas, adaptive radiations, major innovations Significant Events - sea-level changes, volcanic eruptions, bolide impacts, extinctions Paleozoic World Paleozoic Life Figure from Fan et al. (2020) Paleozoic World Paleozoic Timescale Data from ICS (2019) Paleozoic World Phanerozoic Era Durations 300 240 180 120 Duration (myr) 60 0 Paleozoic Mesozoic Cenozoic Data from ICS (2020) Paleozoic World Paleozoic System Durations 70 56 42 28 Duration(myr) 14 0 Camb. Ord. Sil. Dev. Carbon. Perm. Data from ICS (2020) Paleozoic World Paleozoic Paleogeography Animation from Algol (2016: https://www.youtube.com/watch?v=ovT90wYrVk4) Paleozoic World Paleozoic Paleoenvironment Atmospheric O Atmospheric CO 2 2 35 5000 28 4000 21 3000 14 2000 Percent byVol. 7 PerMillionParts 1000 0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Mean Surface Temperature Sea Level 25 250 20 200 15 150 10 Present 100 Meters Above Meters Degrees Celsius 5 50 0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Cambrian Cambrian Timescale System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 485.4 ± 1.9 Stage 10 489.5 Furongian Jiangshanian 494.0 Paibian 497.0 Guzhangian 500.5 Miaolingian Drumian 504.5 Wuliuan 509.0 Stage 4 Cambrian Series 2 514.0 Stage 3 521.0 Stage 2 Terreneuvian 529.0 Fortunian 541.0 ± 1.0 ICS International Chronostrat. Chart 2020/03 Cambrian Paleozoic System Durations 70 56 42 28 Duration(myr) 14 0 Camb. Ord. Sil. Dev. Carbon. Perm. Data from ICS (2020) Cambrian Tectonic Configuration Laurentia (North America) Baltica (Scandinavia, eastern Europe, northwestern Russia) Siberia (Siberia Kazakistan) Single supercontinent (Gondwana) with three island continents Map from Scotese PaleoMap Project (2000) Cambrian Marine Circulation Unimpeded circum-Arctic cold current Broken circum-equatorial current Impeded circum-Antarctic cold current Upwelling zone off southeastern Gondwana Complex circulation patterns Map from Scotese PaleoMap Project (2000) Cambrian Paleozoic Paleoenvironment Atmospheric O Atmospheric CO 2 2 35 5000 28 4000 21 3000 14 2000 Percent byVol. 7 PerMillionParts 1000 0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Mean Surface Temperature Sea Level 25 250 20 200 15 150 10 Present 100 Meters Above Meters Degrees Celsius 5 50 0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Cambrian Climate Zones Comparative Criteria Cambrian O2 Content of 12.5% vol. % Atmosphere (+63%) CO2 Content of 4,500 ppm Atmosphere (x16) Mean Surface 21°C Temperature (+7°C) Sea Level +30m - 90m Tropical (Greenhouse) World Broad equatorial arid region High continentality Ice at poles in Early Cambrian, retreating later Map from Scotese PaleoMap Project (2000) Cambrian Biodiversity 800 Diversification of Cambrian Biota 600 400 Modern Fauna 200 Paleozoic Fauna NumberFamilies of Cambrian Fauna 0 Cambrian Ordovician Sil. Devonian Carbon. Permian Tri. Jurassic Cretaceous Tertiary 500 400 300 200 100 0 Geological Time Data from Sepkoski (1981) Cambrian Biodiversity Figure from Fan et al. (2020) Cambrian Cambrian Evolutionary Fauna Trilobite Graptolite Monoplacophoran Inarticulata Hyolith Cambrian Paleozoic Evolutionary Fauna Articulata Crinoid Tabulate Coral Ostracod Rugose Coral Cambrian Modern Evolutionary Fauna Bivalve Gastropod Echinoid Bony Fish Cambrian Cambrian “Explosion” Increase in O2 levels Increase in calcium concentration in seawater Development of homeobox (Hox) genes, a level of genetic organization that facilities the assembly of different structures in different parts of the body. Initiation of ecological “arms races” “Cambrian Explosion”: sudden Vacant ecospace after appearance of most animal phyla in Ediacaran extinction the fossil record Complexity threshold breach Cambrian Cambrian “Explosion” Fauna Marrella Hallucigenia (Arthropod Acestor) (??? Acestor) Wiwaxia Archaeopirapula Trilobite (Mollusc Acestor) (Pirapulid Ancestor) (Crustacean Ancestor) Cambrian Cambrian “Explosion” Fauna Anomalicaris (Arthropod Ancestor) Cambrian Cambrian “Explosion” Diagram from Morris (2000) Cambrian Cambrian “Explosion” Diagram from Cooper & Fortey (1998) Cambrian Reefs Archaeocyathid Reef Archaeocyathid Reefs The earliest known reefs Constructed by archaeocyathids and receptaculid sponges Archaeocyths are an extinct group of shallow marine, warm-water, sponge- like marine invertebrates especially common in Lower Cambrian sediments. Map from Scotese PaleoMap Project (2000) Diagram from McKerrow (1978) Cambrian Terrestrial Environments Naked Land Surface No plants or animals No soils, but much regolith Complete range of non-biotic surface processes in operation Cambrian Global Climate (Early Cambrian) Diagram from Hearing et al. (2018) Cambrian Extinctions End-Ordovician End-Devonian End-Permian End-Triassic End-Cretaceous 80 Palaeozoic Mesozoic Cenozoic Cambrian 60 40 PercentExtinction 20 0 Cambrian Ord. Sil. Dev. Carb. Perm. Trias. Jurassic Cretaceous Paleoc. Neo. Paleozoic Mesozoic Cenozoic Data from Sepkoski (1998) Cambrian Biomere Extinctions Biomere - Cambrian stage-level, extinction-bounded, trilobite-based biostratigraphic successions characteristic of shallow-water Laurentian sediments in North America. Figures from Thomas (1995) Cambrian Biomere Extinctions Allison (Pete) Palmer James Stitt (b. 1927) (19?? - 2016) Cambrian Biomere Extinctions Tables from Taylor (2006) Cambrian Biomere Extinctions Interval 4 (Extinction Interval): characterized by Interval 3 survivors. Interval 3 (Diversification Interval): characterized by endemic speciation + recruitment to achieve further taxonomic + morphological diversification Interval 2 (Diversification Interval): characterized by endemic speciation + recruitment to achieve enhanced taxonomic diversity. Interval 1 (Post-extinction Interval) - characterized by recruitment of new species from offshore habitats. Figure from Taylor (2006) Cambrian Biomere Extinction Causes: Palmer-Stitt Model Falling sea-level forces continental shelf faunas to migrate to the shelf edges where they compete for limited resources with themselves and shelf-margin species Eustatic sea-level rise causes the thermocline to migrate onto the continental shelves cooling the marine environment and reducing O2 content. Diagram from Palmer (1984) Cambrian Biomere Extinction Causes: Saltzman-Knoll Model Correlatable carbon isotopic excursions in basins from different continents indicate that the pterocephaliid and ptychaspid extinctions were caused by exunic seawater rising onto the continental shelves in a global marine event caused by eustatic sea- level rise. Steptoean Positive Carbon Isotope Excursion (SPICE) Most likely both the Palmer-Stitt and Saltzman-Knoll mechanisms were responsible for aspects of the biomere extinctions Diagram from Saltzman et al (2000) Ordovician Paleozoic World Paleozoic System Durations 70 56 42 28 Duration(myr) 14 0 Camb. Ord. Sil. Dev. Carbon. Perm. Data from ICS (2020) Ordovician Timescale System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 443.8 ± 1.5 Hirnantian 445.2 ± 1.4 Upper Katian 453.0 ± 0.7 Sandbian 458.4 ± 0.9 Darriwillian Middle 467.3 ± 1.1 Dapingian Ordovician 470.0 ± 1.4 Floian Lower 477.7 ± 1.4 Tremadocian 485.4 ± 1.9 ICS International Chronostrat. Chart 2020/03 Ordovician Paleogeography Gondwana drifts south and rest over the South Pole by the end of the Ordovician Sea-level regression causes Laurentia, Siberia & Baltica to emerge. Massive glaciation in Late Ordovician Expansion of the Paleo-Tethys ocean w/ rotation of Gondwana, Laurentia, Siberia & Baltica Map from Scotese PaleoMap Project (2000) Ordovician Marine Circulation