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Late Paleozoic Life & Extinctions

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Late Paleozoic World, Life & Extinctions Norman MacLeod School of Earth Sciences & Engineering, Nanjing University Late Paleozoic World, Life & Extinctions Objectives Understand the structure of the Late Paleozoic (Carbon- iferous - Permian world in terms of timescales, geo- graphy, environments, and organisms. Understand the structure of Late Paleozoic extinction events. Understand the major Late Paleozoic extinction drivers. Understand the degree to which these putative drivers correlate with Late Paleozoic extinction events. Late Paleozoic World, Life & Extinctions Presentation Topics Stratigraphy - chronostrati- graphy & geochronology Geography - tectonics & distribution Climate - circulation, temp- erature, weather Biota - protists, inverte- brates, vertebrates, plants Evolution - evolutionary faunas, adaptive radiations, major innovations Significant Events - sea-level changes, volcanic eruptions, marine anoxia events, bolide impacts, extinctions Carboniferous Carboniferous Paleozoic System Durations 75 60 45 30 Duration(myr) 15 0 Camb. Ord. Sil. Dev. Carbon. Perm. Data from ICS (2020) Carboniferous Timescale System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 ± 0.15 Gzhelian Upper 303.7 ± 0.1 Kasimovian 307.0 ± 0.1 Middle Moscovian 315.2 ± 0.2 Pennsylvanian Lower Bashkirian 315.2 ± 0.2 Upper Serpukhovian 323.2 ± 0.4 Carboniferous Middle Visean 346.7 ± 0.4 Tournasian Mississippian Lower 358.9 ± 0.4 ICS International Chronostrat. Chart 2020/03 Carboniferous Tectonic Configuration Pangea becomes unified and occupies southern polar region with Euramerica (= Laurentia + Avalonia + Baltica) & Siberia forming satellite continents separated from (former) Gondwana by a broad seaway in the Early Carboniferous the former joined to Gondwana (to form Pangea by the Late Carboniferous. Northern seaway referred to as Iapetus Ocean Southern seaway referred to as the Rheic Ocean Both Iapetus and Rhetic Oceans close during the Interval … … leaving the Paleo- Tethys, Panthalassic Ocean (= Proto-Pacific). Map from Scotese PaleoMap Project (2001) Carboniferous Tectonic Configuration Pangea becomes unified and occupies southern polar region with Euramerica (= Laurentia + Avalonia + Baltica) & Siberia forming satellite continents separated from (former) Gondwana by a broad seaway in the Early Carboniferous the former joined to Gondwana (to form Pangea by the Late Carboniferous. Northern seaway referred to as Iapetus Ocean Southern seaway referred to as the Rheic Ocean Both Iapetus and Rhetic Oceans close during the Interval … … leaving the Paleo- Tethys, Panthalassic Ocean (= Proto-Pacific). Map from Scotese PaleoMap Project (2001) Carboniferous Marine Circulation Simplified, but hemispherically heterogeneous circulation patterns. Strong circum-Arctic cold current Disrupted circum-equatorial current Northern & southern Paleo- Tethys gyres Broken circum-Antarctic cold current Upwelling zone off western Euamerica & northern Gondwana Map from Scotese PaleoMap Project (2001) Carboniferous 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. Carboniferous Climate Zones Comparative Criteria Silurian O2 Content of 32.3% vol. % Atmosphere (+162%) CO2 Content of 800 ppm Atmosphere (x3) Mean Surface 14°C Temperature (0°C) Sea Level +120m - 0m - +20m Characterized by high sea-levels and a marked greenhouse effect resulting from high atmospheric CO2 concentrations Greatly expanded tropical, arid & temperate belts Clear southern ice cap early, melting as interval proceeds Falling sea levels through Moscovian, then rising sea levels Draining, the refolding of continental platforms Map from Scotese PaleoMap Project (2000) Carboniferous Cambrian Evolutionary Fauna Trilobite Graptolite Inarticulata Monoplacophora Hyolith Carboniferous Paleozoic Evolutionary Fauna Articulata Crinoid Tabulate Coral Bryozoan Ammonite Ruose Coral Carboniferous Modern Evolutionary Fauna Bivalve Gastropod Echinoid Bony Fish Carboniferous Reefs Carboniferous Reef Widespread reef formation in epicontinental seas, becoming progressively more restricted geographically as the tropical Iapetus and Rhetic seas close. Laurentia / Euamerica Baltica Siberia Northern Gondwana Map from Scotese PaleoMap Project (2000) Carboniferous Reefs Carboniferous deep-water reefs were typically characterized as mud mounds. Core of reef-forming organisms (e.g., bryozoans, crinoids) created topological reef by baffling lime mud around themselves Carboniferous mud reefs had no apparent framework Began in deeper water, but could grow into shallower depths Microbial reef organisms important elements of reef composition/construction Reef structure attracted a host of marine benthos & nekton Diagram from Wood (1998) Carboniferous Fish Platystomus Rhizodus Latimeria Acrolepis Carboniferous Fish Carboniferous Elasmobranchs Akmonistion Diploselache Hybodontid Damocles serrates Carboniferous Elasmobranchs Carboniferous Terrestrial Environment Adjacent to the low and mid-latitude shallow seas were dense tropical forests that form the basis for thick and laterally extensive coal deposits. Temperate forests and steppes were present at higher latitudes Plants Arthropods (incl. insects) Amphibians The first reptiles Carboniferous Terrestrial Scene Carboniferous Terrestrial Environment Equisetales Sphenophyllales Lycopodiales Lepidodendrales Filicales (Horse Tails) (Scramblers) (Club Mosses) (Scale Trees) (Ferns) Cordaitales Cycadophyta (Early Conifers) (Cycads) Carboniferous Terrestrial Environment Carboniferous Forest Carboniferous Terrestrial Arthropods Terrestrial arthropods were able to grow to such enormous sizes because of the high concentration of O2 in the Carboniferous atmosphere (32.3% vol. %, or +162% present day concentrations) Arthropleura (Largest known land arthropod: Length 2.5 m) Pulmonoscorpius Carboniferous Terrestrial Insects Dictyoptera (Cockroach Ancestor) Meganeura Protorthoptera (Largest known insects: wingspan c. 75 cm) (Earliest known Winged Insect) Palaeodictyoptera (Superorder: 50% of all known insects) Carboniferous Quadrupeds (Amphibians) Eyrops Pederpes (Labyrinthodont: Temnospondyl) (Labyrinthodont) Hyloplesion (Lepospondyl: Microsauria) Dioplocaulus (Lepospondyl: Lissamphibian) Ophiderpeton (Lepospondyl: Aïstopod) Carboniferous Quadrupeds (Amphibians) Chart from Roelants et al. (2005) Carboniferous Amphibian - Reptile Transition Reptiles appear in the fossil record in the Late Carboniferous Reptile Characteristics Strong skeletal Advanced lung & leg Development of hard- structure designs shelled eggs (and Protective coating for Loss of gills possibly paternal egg- incubation behaviors) skin (scales) Dominantly carnivorous Increased brain size Carboniferous Reptile Cranium Types Anapsid Synapsid Parapsid Euryapsid Diapsid Carboniferous Quadrupeds (Reptiles) Protoclepsydrops Gephyrostegus Hylonomus (Earliest Reptile) Petrolacosaurus (Early Diapsid) Archaeothyris (Early Synapsid) Carboniferous Biodiversity 800 600 Carboniferous Extinction 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) Carboniferous Biodiversity Figure from Fan et al. (2020) Carboniferous Extinctions End-Ordovician End-Devonian End-Permian End-Triassic End-Cretaceous 80 Palaeozoic Mesozoic Cenozoic Carbonif. 60 40 PercentExtinction 20 0 Cambrian Ord. Sil. Dev. Carb. Perm. Trias. Jurassic Cretaceous Paleoc. Neo. Paleozoic Mesozoic Cenozoic Data from Sepkoski (1998) Carboniferous Extinctions System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Gzhelian Upper 303.7 Kasimovian Mid-Carboniferous 307.0 Extinction event Middle Moscovian Ammonites Pennsylvanian 315.2 Conodonts Lower Bashkirian 315.2 Crinoids Upper Serpukhovian Brachiopods 323.2 Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 No. Of Genera ICS International Chronostrat. Chart 2020/03 Carboniferous Sea-Level Changes System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Gzhelian Upper 303.7 Kasimovian 307.0 Middle Moscovian Pennsylvanian 315.2 Lower Bashkirian 315.2 Upper Serpukhovian 323.2 Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 0.5 0.0 200 100 0 No. Of Genera Onlap Sea Level ICS International Chronostrat. Chart 2020/03 Carboniferous Ocean Anoxia Events System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Gzhelian Upper 303.7 Kasimovian 307.0 Middle Moscovian Pennsylvanian 315.2 Lower Bashkirian 315.2 Upper Serpukhovian 323.2 Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 No. Of Genera ICS International Chronostrat. Chart 2020/03 Carboniferous LIP Eruptions System/ Numerical Period Series/Epoch Stage/Age Age (Ma) 289.9 Skagerrak (150 Kkm2) Gzhelian Upper 303.7 Kasimovian 307.0 Middle Moscovian Pennsylvanian 315.2 Lower Bashkirian 315.2 Kennedy-Conors- Upper Serpukhovian Auburn (500 Kkm2) 323.2 Tianshan (250 Kkm2) Middle Visean Carboniferous 346.7 Mississippian Lower Tournasian 358.9 0 900 1800 No. Of Genera ICS International Chronostrat. Chart 2020/03 Carboniferous LIP Eruptions Kennedy-Conors-Auburn Large Igneous Province
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  • Insects Took Off When They Evolved Wings 23 January 2018, by Ker Than

    Insects Took Off When They Evolved Wings 23 January 2018, by Ker Than

    Insects took off when they evolved wings 23 January 2018, by Ker Than author Sandra Schachat, a graduate student at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth). Many ideas have been proposed to explain this curious lacuna in the insect fossil record, which scientists have dubbed the Hexapod Gap. According to one popular hypothesis, insect size and abundance were limited by the amount of oxygen available in Earth's atmosphere during the late Devonian period. When insects such as this Meganeura monyi, which had a wingspan of about 27 inches, developed wings roughly The strongest evidence for this theory is a model of 325 million years ago, the insect population exploded, atmospheric oxygen during the past 570 million Stanford researchers found. Credit: Alexandre Albore, years that the late Yale geologist Robert Berner Wikimedia Commons developed by comparing ratios of oxygen and carbon in ancient rocks and fossils. According to Berner's model, the atmospheric The evolution of wings not only allowed ancient oxygen level about 385 million years ago during the insects to become the first creatures on Earth to start of the Hexapod Gap was below 15 percent, so take to the skies, but also propelled their rise to low that wildfires would have been unsustainable. become one of nature's great success stories, (For comparison, today's atmospheric oxygen according to a new study. concentration is about 21 percent.) Comprising up to 10 million living species, insects Another possibility is that insects were abundant today can be found on all seven continents and before 323 million years ago, but don't show up in inhabit every terrestrial niche imaginable.