Introduction to Extinction (Pdf)

Introduction to Extinction

Norman MacLeod School of Earth Sciences & Engineering, Nanjing University Extinctions: Week 1 Objectives

Introduce the concept of extinction.

Explain importance of extinction as a natural phenomenon.

Review (briefly) record of organismal extinctions. Deep Time (ca. 600 million ybp - 5000 ybp) Historical (ca. 5000 ybp - Present) Future (ca. Present - 1000 yap)

Review prospective extinction causes. Endangered Species Mass Extinction Underway Human Impact on the Planet What is Extinction? What is Extinction?

Extinction - the complete termination of an organism or group of organisms, usually a species, without the survival of any descendants.

Extripation - the condition of an organism, or group of organisms (usually a species) that has ceased to exist in a chosen geographic area while still existing elsewhere. Also referred to as local extinction.

Pseudoextinction - the complete evolutionary transformation of one species into another such that no individual assignable to the prior species exists. Extinction Nomenclature

Extinct species - a species all of whose members have died without leaving any progeny.

Examples of Extinct Species

Triceratops horridus Mammuthus primigenius Thylacinus cinocephalus (Woolly Mammoth) (Tasmanian Tiger) Extinction Nomenclature

Extripation - a group of organisms (usually a species) that has ceased to exist in a geographic area while still existing elsewhere. Examples of Extripated Species (UK)

Alces alces Lycaena dispar Hyla aborea (Elk or Moose) (Large Copper) (European Tree Frog) Extinction Nomenclature

Ghost Species - a species (or other taxon) declared extinct, but which has been sighted, by non-professional observers, at a later date. Examples of Ghost Species

Lipotes vexillifer Canis lupus hodophilax (Yangtze River Dolphin) (Japanese Wolf) Extinction Nomenclature

Lazarus Species - a species (or other taxon) declared to have become extinct, but which has been (re)discovered by qualified observers at a later date. Examples of Lazarus Species

Latimeria chalumnae Campephilus principalis Heosemys depressa (Coelocanth) (Ivory-Billed Woodpecker) (Arakan Forest Turtle) Extinction Nomenclature

Zombie Species - extant species whose individuals have lost the ability to reproduce.*

Examples of Zombie Species

Dedeckera eurekensis Adenostoma sparsifolium Xylococcus bicolor (July Gold) (Redshanks) (Mission Manzanita)

* This term has also been used to describe a fossil species that has been eroded and redeposited in younger sediments (= reworked), thus mimicking an extinction survivor species. Extinction Nomenclature

Elvis Species - a species Example of an that has been redis- Elvis Species covered after being presumed extinct, but has been discovered not to belong to the extinct taxon subsequently. This is usually the result of mistaken taxonomy or extreme morphological convergence.

Lobothyris subgregaria (formerly Rhaetina gregaria) Modern Extinctions Modern Extinctions

Examples

Mammals Birds Reptiles Amphibians

Arthropods Fish Molluscs Plants Modern Extinctions

International Union for the Conservation of Nature and Natural Resources

International organization which, since 1948, has been involved in at a collection, analysis, research, advocacy and education to “encourage and assist societies to conserve nature and ensure that any use of natural resources is equitable and ecologically sustainable.”. The IUCN maintains the most https://www.iucnredlist.org comprehensive database available of the extinction status of extant species. Modern Extinctions

Extinct Species by Taxonomic Group

Total Percent Mammalia 83 Total: 926 5,416 1.53 Aves 161 9,500 1.69 Reptilia 33 10,700 0.31

Amphibia 34 8,043 0.42

Fish 72 33,600 0.21

Arthropods 75 5,000,000 0.00

Mollucs 313 85,000 0.37

Plants 155 391,000 0.04

0 160 320 480 640 800 5,543,259 0.02

Extinct Extinct in Wild Modern Extinctions

Extinct & Possibly Extinct by Taxonomic Group

Total Percent Mammalia Total: 1,726 5,416 2.09 Aves 9,500 3.40 Reptilia 10,700 1.00 Amphibia 8,043 2.55 Fish 33,600 0.74 Arthropods 5,000,000 0.01 Mollucs 85,000 0.90 Plants 391,000 0.11

0 160 320 480 640 800 5,543,259 0.03

Extinct Possibly Extinct Extinct in Wild Possibly Extinct in Wild Modern Endangered Species

Endangered Species by Taxonomic Group

Total Percent Mammalia 1,220 Total: 22,630 5,416 22.53 Aves 1,492 9,500 15.71 Reptilia 1,367 10,700 12.78 Amphibia 2,157 8,043 26.82 Fish 2,494 33,600 7.42 Arthropods 2,474 5,000,000 0.05 Mollucs 2,231 85,000 2.62 Plants 14,195 391,000 3.63

0 3,200 6,400 9,600 12,800 16,000 5,543,259 0.40

Critically Endangered Endangered Vulnerable Actual + Predicted Endangered Species

Actual + Predicted Endangered Species (by Taxonomic Group; + 100 years) Total Percent Mammalia 1.172 Total: 26,919 5,416 21.63 Aves 1,660 9,500 17.48 Reptilia 1,293 10,700 12.09 Amphibia 2,050 8,043 25.49 Fish 2,489 33,600 7.41 Arthropods 2,470 5,000,000 0.05 Mollucs 2,813 85,000 3.31 Plants 12,971 391,000 3.32

0 3,000 6,000 9,000 12,000 15,000 5,543,259 0.47

Predicted Extinct Predicted Endangered Modern Extinctions

IUCN Summary: 2020 Animals Plants Extinct 0.1% 4.1% Extinct in Wild 0.1% Critically Endangered 0.4% Endangered 1.0% Vulnerable 7.2% 9.0% Conservation Dependent 18.6% 6.5% Neat Threatened Least Concern Data Deficient 8.5% 15.0% 0.0% 6.0%

42.9%

18.7%

0.5% 55.2% n = 71,861 n = 33,238 6.2% Ancient Extinctions Ancient Extinction Data

The Sepkoski Database

Sepkoski, J. J., Jr., 1982. A Sepkoski Jr., J. J. (2002). A compendium of fossil marine compendium of fossil families: Milwaukee Public marine animals. In D. Museum Contributions in Jablonski & M. Foote Biology and Geology, v. 51, p. (Eds.), Bulletins of 1-125. American Palaeontology 363. Ithaca, New York: A listing of over 3,500 family- Palaeontological Research level records consisting of of taxonomic assignments and Institution. stratigraphic ranges referenced to stratigraphic stages and a A listing of over 37,000 common geological time scale. genus-level records consisting of of taxonomic Updated subsequently: assignments and Sepkoski, stratigraphic ranges J. J. Jr, 1992, A compendium of referenced to stratigraphic fossil marine animal families, stages and a common 2nd edition, Milwaukee, geological time scale. Wisconsin, Milwaukee, Public Museum, Contributions in Biology and Geology, 156 p. Ancient Biodiversity

Phanerozoic Family Richness

800

600

400

200 NumberFamiliesof

0 Cambrian Ordovician Sil. Devonian Carbon. Permian Tri. Jurassic Cretaceous Tertiary 500 400 300 200 100 0 Geological Time

Data from Sepkoski (1981) Ancient Biodiversity

Phanerozoic Family Richness

800

600

400

Modern Fauna

200 NumberFamiliesof Paleozoic Fauna

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) Ancient Biodiversity

Phanerozoic Family Richness

800

600

400 Gastropoda Bivalvia Osteichthyes Nakacistraca Articulata Echinoidea Crinoidea Gymnolaemata 200 Ostracoda Demospongia NumberFamiliesof Cephalopoda Chondrichthyes Anthrozoa Trilobita Polychaeta Stenolaemata Monoplacophora Stelloeroidea Inarticulata 0 Cambrian Ordovician Sil. Devonian Carbon. Permian Tri. Jurassic Cretaceous Tertiary 500 400 300 200 100 0 Geological Time

Data from Sepkoski (1981) Cambrian Evolutionary Biota

Trilobita Polychaeta

Monoplacophora Inarticulata Paleozoic Evolutionary Biota

Articulata Crinoidea Ostracoda Cephalopoda

Anthrozoa Stenolamata Stelleroidea Modern Evolutionary Biota

Gastropoda Bivalvia Osteichthyes Nakacistraca

Echinoidea Gymnolaemata Demospongia Chondrichtyes Ancient Biodiversity

Phanerozoic Family Richness

800 End-Cretaceous Late Devonian End-Ordovician End-Permian End-Triassic 600

Data from Sepkoski (1981) Ancient Biodiversity

Phanerozoic Genus Richness

3000 End-Cretaceous Late Devonian 2500 End-Ordovician End-Permian

2000 End-Triassic

1500

1000 Modern Fauna NumberGeneraof 500 Paleozoic Fauna Cambrian Fauna 0 Cambrian Ordov. Sil. Dev. Carbon. Permian Tri. Jurassic Cretaceous Paleogene 500 400 300 200 100 0 Geological Time

Data from Sepkoski (2001) Percent Extinction 20 40 60 80 0 Phanerozoic Extinction-Intensity Spectrum Extinction-Intensity Phanerozoic Ancient Extinction Peaks Extinction Ancient

End-Ordovician

End-Devonian

End-Permian

End-Triassic Cenozoic Palaeozoic Data from Sepkoski (1998) from Data Sepkoski End-Cretaceous Mesozoic Transcending Taxonomic Limits

Field-of-Bullets Model

A simulation based on the concept of constant extinction susceptibility that takes a sample of families, genera and species and asks the question “on average how many species extinctions does it take to eliminate a genus or a family?”

10 Families 10 Genera/Family 10 Species/Genus Transcending Taxonomic Limits

Taxonomic Rarefaction

These curves summarize a Orders series of simulation experiments

Families in which random elimination of species (= equal probability of Genera extinction) was used to estimate how many species extinctions would be necessary into to remove larger taxonomic groups. These curves look reasonable insofar as their inflection points grow more pronounced and migrate to the left as taxonomic generality increases. But they do assume a taxonomic structure that’s far from reality. Transcending Taxonomic Limits

Taxonomic Rarefaction

Pros Orders Families Constitute a means to estimate statistically Genera expected percent species extinction based on data at any taxonomic level. Results susceptible to empirical verification. Can be used to estimate mechanism-specific ‘kill curves’. Cons Dependent on accuracy (and reality) of taxonomic data. Results dependent of appropriateness of the model used to simulate the range of actual taxonomic groups (e.g., no. of monospecific genera & families). Assumption that all species are equally susceptible to extinction is generally regarded as unrealistic. Transcending Taxonomic Limits

Taxonomic Rarefaction

Stage Age (Myr) Families (%) Genera (%) Species (%)

End-Ordovician 439 26 ± 1.9 60 ± 4.4 85 ± 3.0

End-Devonian 367 22 ± 1.7 52 ± 3.3 83 ± 4.0

End-Permian 245 51 ± 2.3 69 ± 3.8 95 ± 2.0

End-Triassic 208 22 ± 2.2 60 ± 4.4 80 ± 4.0

End- 66 16 ± 1.5 47 ± 4.1 76 ± 5.0 Cretaceous

Despite the various assumptions and caveats that pertain to such estimates, these magnitudes appear astonishingly large.

Data from Jablonski (1995) Transcending Taxonomic Limits

Taxonomic Rarefaction

Stage Age (Myr) Families (%) Genera (%) Species (%)

End-Ordovician 9.60 2.71 6.25 8.85

End-Devonian 23.80 0.92 2.18 0.97

End-Permian 7.63 6.68 9.04 12.45

End-Triassic 25.70 0.86 2.33 3.11

End- 6.10 2.62 7.70 12.46 Cretaceous

However, when time averaged they yield surprisingly low extinction rates (per million years).

Data from Jablonski (1995) Ancient Extinctions: Causes

Sea-Level Change Volcanism

Marine Anoxia Climate Change Bolide Impact The list of causal mechanisms that have been put forward in the scientific literature ranges into the 100s. However, these are the most popular mechanisms currently and the ones that have received the most extensive testing. Extinction Mechanisms

Sea-Level Change

Reduced shelf area (habitat Geological Sea Level Systems destruction, ecological crowding)

Tertiary Increased continentality (climate change) Present Cretaceous Sea Level Increased albedo (cooling) Jurassic Greenhouse gases emissions Triassic (warming) Permian

Carboniferous Changes in the level of the oceans have also happened repeatedly throughout Devonian Earth history and have long been Silurian regarded as potential causes of major

Ordovician extinction events. Fluctuations of 100s of meters are not uncommon. These events Cambrian take place of quite long periods of geological time.

1.0 0.5 0.0 Extinction Mechanisms

Sea-Level Change Extinction Mechanisms

Marine Anoxia

Widespread and complete decimation of benthic marine and, in some cases nektonic and planktonic biota Collapse of marine primary productivity (leading to starvation of groups not effected directly) Can be caused by wide variety of mechanisms (e.g., transgression, climatic This mechanism actually represents a temperature rise, marine nutrient set of different mechanisms unified by fluctuations, weathering) the effect they have on the depth distri- bution of oxygen in the ocean basins. Evidence for repeated marine anoxia events is provided by the widespread occurrence of black shales in the stratigraphic record. However, this occurrence pattern also raises the issue of coincidental association. Extinction Mechanisms

Marine Anoxia

Deceased Marine Global Warming Circulation

Ocean Lowering of O2 Levels Pyrite Burial Stagnation

Productivity Lowering of !34S Collapse Values in Evaporites Mass Extinction

Marine Lowering of Eutrophication !13C Values

Black Shale Algal Bloom Deposition Extinction Mechanisms

Volcanism: Large Igneous Provinces (LIPs) Extinction Mechanisms

Volcanism: Large Igneous Provinces (LIPs)

Local devastation (physical damage) Increased albedo (cooling) Increased greenhouse gases (warming) Acid rain (habitat damage) Quasi-continuous disruption of global cycles

Large Igneous Province volcanism has happened repeatedly throughout Earth history and has led to the emplacement of (literally) millions of cubic miles of lava and other volcanic deposits on the earth’s surface. Time scales for such eruptions stretch to as much as a million years.

Diagram from Coffin & Eldholm (1994) Extinction Mechanisms

Volcanism: Large Igneous Provinces (LIPs)

Diagrams from Ernst & You (2017) Extinction Mechanisms

Volcanism: Large Igneous Provinces (LIPs)

Diagrams from Ernst & You (2017) Extinction Mechanisms

Bolide Impact

Thermal flash (wildfires) Shock wave (physical damage) Global darkness (cooling) Increased albedo (cooling) Increased greenhouse gases (warming) Acid rain (habitat damage)

Because this mechanism represents a short, sharp, shock to the biosphere timing considerations and recurrence patterns are paramount. Direct global effects of a large bolide impact are not estimated last more than 100 years. Extinction Mechanisms

Bolide Impact

Stratospheric CO2 SO2 Shock Wave Thermal Flash Ballistic Ejecta Dust Release Release

Proximate Global Increased Global Wildfires Acid Rain Extinctions Darkness Albedo Temp. Rise

Global Cooling

Altered Terres- Productivity Altered Marine trial Habitats Collapse Habitats

Extinctions Extinction Mechanisms

Multiple Causes

Thermal flash (wildfires) Shock wave (physical damage) Global darkness (cooling) Increased albedo (cooling) Increased greenhouse gases (warming) Acid rain (habitat damage) Quasi-continuous disruption of global cycles Reduced shelf area (habitat destruction) Increased continentality (climate change) Since it’s unquestionable that impacts, eruptions, sea-level changes and anoxia events were taking places various times in earth history, all may have played a role in driving the extinctions recorded there. Percent Extinction 20 40 60 80 0 Phanerozoic Extinction-Intensity Spectrum Extinction-Intensity Phanerozoic Ancient Extinctions: EffectsExtinctions: Ancient

End-Ordovician

End-Devonian

End-Permian

End-Triassic Cenozoic Palaeozoic Data from Sepkoski (1998) from Data Sepkoski End-Cretaceous Mesozoic Ancient Extinctions: Effects

Does Any Good Ever Come From Extinction? Ancient Extinctions: Effects

Alteration of Selective Regimes

Large extinction events that happen suddenly can alter the character of natural selection profoundly from selective regimes extant during normal times (e.g., emphasize survival of physical changes in the environment as opposed to competitive interactions between species).

Pervious species-specific adaptive advantages may not confer the same survivorship potential during the former, as opposed to the latter, intervals.

The role of chance in determining patterns of survivorship increases (e.g., bad genes or bad luck). Ancient Extinctions: Effects

Alteration of Selective Regimes

Selection for Individual Selection for Group Ancient Extinctions: Effects

Reduction of Incumbency Advantage

Clades the diversify early can block the diversification of equally well-adapted clades (e.g., dinosaurs vs mammals).

Large & sudden extinction events can act to release this blockage by changing the character of selection and increasing the likelihood of both fair competition and opportunistic survivorship.

There are a number of examples in the history of life in which this mechanism appears to have operated and resulted in dramatic changes to both faunas and floras over rapid time scales. Ancient Extinctions: Effects

Reduction of Incumbency Advantage

Explosive Paleogene Diversification of Mammal Size

Slater (2013) Ancient Extinctions: Effects

Biodiversity Enhancement Through Evolutionary- Ecological Stacking

While large numbers of extinctions take place during large extinction events, it is rare that all members of previously diverse groups are eliminated (e.g., the end-Permian extinction eliminated trilobites, but not arthropods).

This persistence leads to and evolutionary stacking of clades over time as extinction provides opportunities for new evolutionary innovation without dispensing completely with older designs. Ancient Extinctions: Effects

Biodiversity Enhancement Through Evolutionary- Ecological Stacking

Accumulation of Vertebrate Biodiversity

End-Cretaceous Extinction 80

End-Jurassic Extinction Birds

60 End-Triassic Extinction

Mammals 40 End-Permian Extinction

20 Amphibians Reptiles (incl.

NumberOrders of Dinosaurs) Bony Fish Lobe-finned Fish Jawless Vertebrates Holostean Fish Sharks & Rays 0 Cambrian Ordovic. Sil. Dev. Carbon. Perm. Triassic Jurassic Cret. Tertiary 500 400 300 200 100 0 Geological Time (Millions of Years Before Present) Data from Romer (1966) Introduction to Extinction

Norman MacLeod School of Earth Sciences & Engineering, Nanjing University