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 PercentbyVol. 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
DegreesCelsius 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 PercentbyVol. 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
DegreesCelsius 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 NumberFamiliesof
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
Unimpeded circum- Arctic cold current Impeded circum- equatorial current No circus-antarctic cold circulation Upwelling zones off western coasts of Laurentia and northern Gondwana
Complex circulation patterns
Map from Scotese PaleoMap Project (2000) Ordovician
Paleozoic Paleoenvironment
Atmospheric O Atmospheric CO 2 2 35 5000
28 4000
21 3000
14 2000 PercentbyVol. 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
DegreesCelsius 5 50
0 0 Camb. Ord. Sil. Dev. Carbon. Perm. Camb. Ord. Sil. Dev. Carbon. Perm. Ordovician
Climate Zones
Comparative Criteria Ordovician
O2 Content of 13.5% vol. % Atmosphere (+68%)
CO2 Content of 4,200 ppm (x15) Atmosphere
Mean Surface 16°C (+2°C) Temperature
Sea Level +180m-220m
Temperate ➔ Cold (Icehouse) World Narrowed equatorial arid region High continentality Distinctly expanded southern cold zone at southern pole
Map from Scotese PaleoMap Project (2000) Ordovician
Marine (Neritic) Environment
Great Ordovician Biodiversification Early Ordovician Cambrian- Event (GOBE) fauna acme Diversification of Paleozoic Evolutionary Fauna Archaeocyathid reefs replaced by rugose-tabulate coral & bryozoan reefs. Rise of echinoderms, mollucs and articulate brachiopods. Replacement of Cambrian trilobites with Ordovician descendants. First fish.
Ordovician Marine Scene Ordovician
Terrestrial Environment
Initial invasion of terrestrial habitats First terrestrial plants appear in marginal aquatic environments First arthropods on land as evidenced by preserved trackways Evidence of first soils Evidence of first terrestrial burrows (probably made by arthropods) Away from watercourses, however, the Ordovician landscape was barren
Ordovician Terrestrial Scene Ordovician
Biodiversity
800 Great Ordovician Biodiversification Event (GOBE)
600 End-Ordovician Extinction Event
400
Modern Fauna
200 Paleozoic Fauna NumberFamiliesof
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) Ordovician
Biodiversity
Figure from Fan et al. (2020) Ordovician
Plankton Revolution
Plankton - aquatic species unable to swim against a current (Graptoloidea, Dacryoconarida, Homoctenida, Orthocerids, Bactritida).
Demersal Taxa - acquatic species that live in the water column but close to the sea floor (Cephalopoda: Actinocerida, Ascocerida, Discosorida, Ellesmerocerida, Endocerida, Lituitida, Oncocerida; Arthropoda: Radiodonta, Eurypterida; Vertebrata: Galeaspida, Osteostraci, Pteraspidomorphi, Thelodonti; Cephalochordata).
Nekton - aquatic species able to swim and move independent of water currents (Ammonoidea, Gnathostomata, most coiled nautiloids). Ordovician
Plankton Revolution
Data from Servais et al. (2015) Ordovician
Plankton Revolution
Data from Sepkoski (2002) Data from Paleobiology Database (2014) Ordovician
Great Ordovician Biodiversification Event (GOBE)
Data from Servais & Harper (2018) Ordovician Cambrian Evolutionary Fauna
Trilobite Graptolite
Inarticulata Polychaeta Eocrinoid Ordovician
Paleozoic Evolutionary Fauna
Articulata Crinoid
Cephalopod
Tabulate Coral Bryozoan Rugose Coral Ordovician Modern Evolutionary Fauna
Bivalve Gastropod Echinoid Bony Fish Ordovician
Reefs
Ordovician Reef
First Coral Reefs Note asymmetrical distribution about equator - indicating cold conditions in the Antarctic Ordovician reefs were much more topologically prominent, taxonomically diverrse, and morphologically diverse than their Cambrian counterparts
Map from Scotese PaleoMap Project (2000) Early Paleozoic World, Life & Extinctions Norman MacLeod School of Earth Sciences & Engineering, Nanjing University