Diversity dynamics of Early Jurassic ostracods of the Cordillera Ibérica (Spain) and the re-evaluation of the Pliensbachian–Toarcian mass extinction

2007 ◽  
Vol 44 (10) ◽  
pp. 1397-1411 ◽  
Author(s):  
Carmen Arias
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Marine Invertebrates ◽  
Marine Species ◽  
Extinction Time ◽  
Extinction Rate ◽  
Extinction Rates ◽  
Cordillera Ibérica ◽  
Global Extinction ◽  
Ultimate Cause

The extinction and recovery of Ostracoda at the Pliensbachian–Toarcian (P–T) boundary are analyzed based on a database of taxonomically revised Pliensbachian to Toarcian transition ostracod assemblages. In contrast to earlier assertions, the results of this study indicate that ostracod extinction rates were significant in comparison with other marine invertebrates. An extinction rate of 54% has been calculated for upper Pliensbachian ostracod species occurring in more than one section. Diversification took place in the latest Pliensbachian (Spinatum Zone) and early Toarcian (Tenuicostatum Zone), whereas diversity decrease occurred in the middle early Toarcian (Strangewaysi Subzone, Serpentinus Zone). This notable diversity decline in the early Toarcian corresponds to a global mass extinction time, whose peak has been documented in the Tenuicostatum Zone. Meanwhile, the ostracod mass extinction occurred within the Serpentinus Zone and was followed by radiation and recovery in the succeeding Bifrons Zone. Similar diversity changes of ostracods are observed in other European areas, although in the Cordillera Ibérica, the demise began later. Many aspects of this event are still debated, and there is no common cause or single set of climatic or environmental changes common to this event. The supposed extinction-causing environmental changes resulting from anoxia episodes are unclear and are unlikely to have been of sufficient intensity or geographic extent to cause this global extinction. In this paper, the decrease in marine species diversity is explained by a new palaeoceanographic scenario, in which a rapid global cooling episode is regarded as the ultimate cause.

scholarly journals Current extinction rate in European freshwater gastropods greatly exceeds that of the late Cretaceous mass extinction

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Thomas A. Neubauer ◽  
Torsten Hauffe ◽  
Daniele Silvestro ◽  
Jens Schauer ◽  
Dietrich Kadolsky ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Recovery Period ◽  
Freshwater Ecosystems ◽  
Extinction Rate ◽  
Freshwater Gastropods ◽  
Extinction Rates ◽  
Freshwater Biota ◽  
Order Of Magnitude ◽  
To Come ◽  
Mass Extinction Event

AbstractThe Cretaceous–Paleogene mass extinction event 66 million years ago eradicated three quarters of marine and terrestrial species globally. However, previous studies based on vertebrates suggest that freshwater biota were much less affected. Here we assemble a time series of European freshwater gastropod species occurrences and inferred extinction rates covering the past 200 million years. We find that extinction rates increased by more than one order of magnitude during the Cretaceous–Paleogene mass extinction, which resulted in the extinction of 92.5% of all species. The extinction phase lasted 5.4 million years and was followed by a recovery period of 6.9 million years. However, present extinction rates in European freshwater gastropods are three orders of magnitude higher than even these revised estimates for the Cretaceous–Paleogene mass extinction. Our results indicate that, unless substantial conservation effort is directed to freshwater ecosystems, the present extinction crisis will have a severe impact to freshwater biota for millions of years to come.

Geographic variation in turnover and recovery from the Late Ordovician mass extinction

Paleobiology ◽  
2007 ◽  
Vol 33 (3) ◽  
pp. 435-454 ◽  
Author(s):  
Andrew Z. Krug ◽  
Mark E. Patzkowsky
Keyword(s):  
Mass Extinction ◽  
Late Ordovician ◽  
Mass Extinctions ◽  
Climatic Fluctuations ◽  
Extinction Rates ◽  
Large Size ◽  
Extinction Event ◽  
Global Extinction ◽  
Rate Of Recovery ◽  
Extinction Events

AbstractUnderstanding what drives global diversity requires knowledge of the processes that control diversity and turnover at a variety of geographic and temporal scales. This is of particular importance in the study of mass extinctions, which have disproportionate effects on the global ecosystem and have been shown to vary geographically in extinction magnitude and rate of recovery.Here, we analyze regional diversity and turnover patterns for the paleocontinents of Laurentia, Baltica, and Avalonia spanning the Late Ordovician mass extinction and Early Silurian recovery. Using a database of genus occurrences for inarticulate and articulate brachiopods, bivalves, anthozoans, and trilobites, we show that sampling-standardized diversity trends differ for the three regions. Diversity rebounded to pre-extinction levels within 5 Myr in the paleocontinent of Laurentia, compared with 15 Myr or longer for Baltica and Avalonia. This increased rate of recovery in Laurentia was due to both lower Late Ordovician extinction rates and higher Early Silurian origination rates relative to the other continents. Using brachiopod data, we dissected the Rhuddanian recovery into genus origination and invasion. This analysis revealed that standing diversity in the Rhuddanian consisted of a higher proportion of invading taxa in Laurentia than in either Baltica or Avalonia. Removing invading genera from diversity counts caused Rhuddanian diversity to fall in Laurentia. However, Laurentian diversity still rebounded to pre-extinction levels within 10 Myr of the extinction event, indicating that genus origination rates were also higher in Laurentia than in either Baltica or Avalonia. Though brachiopod diversity in Laurentia was lower than in the higher-latitude continents prior to the extinction, increased immigration and genus origination rates made it the most diverse continent following the extinction. Higher rates of origination in Laurentia may be explained by its large size, paleogeographic location, and vast epicontinental seas. It is possible that the tropical position of Laurentia buffered it somewhat from the intense climatic fluctuations associated with the extinction event, reducing extinction intensities and allowing for a more rapid rebound in this region. Hypotheses explaining the increased levels of invasion into Laurentia remain largely untested and require further scrutiny. Nevertheless, the Late Ordovician mass extinction joins the Late Permian and end-Cretaceous as global extinction events displaying an underlying spatial complexity.

scholarly journals Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

2016 ◽  
Vol 113 (25) ◽  
pp. 6868-6873 ◽  
Author(s):  
James S. Crampton ◽  
Rosie D. Cody ◽  
Richard Levy ◽  
David Harwood ◽  
Robert McKay ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Atmospheric Carbon Dioxide ◽  
Large Scale ◽  
Species Turnover ◽  
Polar Front ◽  
Extinction Rate ◽  
The Past ◽  
Extinction Rates ◽  
Phytoplankton Communities ◽  
Global Extinction

It is not clear how Southern Ocean phytoplankton communities, which form the base of the marine food web and are a crucial element of the carbon cycle, respond to major environmental disturbance. Here, we use a new model ensemble reconstruction of diatom speciation and extinction rates to examine phytoplankton response to climate change in the southern high latitudes over the past 15 My. We identify five major episodes of species turnover (origination rate plus extinction rate) that were coincident with times of cooling in southern high-latitude climate, Antarctic ice sheet growth across the continental shelves, and associated seasonal sea-ice expansion across the Southern Ocean. We infer that past plankton turnover occurred when a warmer-than-present climate was terminated by a major period of glaciation that resulted in loss of open-ocean habitat south of the polar front, driving non-ice adapted diatoms to regional or global extinction. These findings suggest, therefore, that Southern Ocean phytoplankton communities tolerate “baseline” variability on glacial–interglacial timescales but are sensitive to large-scale changes in mean climate state driven by a combination of long-period variations in orbital forcing and atmospheric carbon dioxide perturbations.

scholarly journals The biogeographical imprint of mass extinctions

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180232 ◽  
Author(s):  
Ádám T. Kocsis ◽  
Carl J. Reddin ◽  
Wolfgang Kiessling
Keyword(s):  
Mass Extinction ◽  
Marine Species ◽  
Mass Extinctions ◽  
Marine Life ◽  
Extinction Rates ◽  
Evolution Of Life ◽  
Severe Reduction ◽  
Permian Extinction ◽  
Extinction Events ◽  
Mass Extinction Events

Mass extinctions are defined by extinction rates significantly above background levels and have had substantial consequences for the evolution of life. Geographically selective extinctions, subsequent originations and species redistributions may have changed global biogeographical structure, but quantification of this change is lacking. In order to assess quantitatively the biogeographical impact of mass extinctions, we outline time-traceable bioregions for benthic marine species across the Phanerozoic using a compositional network. Mass extinction events are visually recognizable in the geographical depiction of bioregions. The end-Permian extinction stands out with a severe reduction of provinciality. Time series of biogeographical turnover represent a novel aspect of the analysis of mass extinctions, confirming concentration of changes in the geographical distribution of benthic marine life.

Evolution and extinction in the marine realm: some constraints imposed by phytoplankton

1989 ◽  
Vol 325 (1228) ◽  
pp. 279-290 ◽  
Keyword(s):  
Mass Extinction ◽  
Evolutionary Biology ◽  
Marine Invertebrates ◽  
Earth Surface ◽  
Calcareous Nannoplankton ◽  
Late Mesozoic ◽  
Planktonic Algae ◽  
Extinction Rates ◽  
Sufficient Detail ◽  
Marine Realm

The organic and mineralized remains of planktonic algae provide a rich record of microplankton evolution extending over nearly half of the preserved geological record. In general, Phanerozoic patterns of phytoplankton radiation and extinction parallel those documented for skeletonized marine invertebrates, both augmenting and constraining thought about evolution in the oceans. Rapidly increasing knowledge of Proterozoic plankton is making possible the recognition of additional episodes of diversification and extinction that antedate the Ediacaran radiation of macroscopic animals. In contrast to earlier phytoplankton history, the late Mesozoic and Cainozoic record is documented in sufficient detail to constrain theories of mass extinction in more than a general way. Broad patterns of diversity change in planktonic algae show similarities across the Cretaceous-Tertiary and Eocene- Oligocene boundaries, but detailed comparisons of origination and extinction rates in calcareous nannoplankton, as well as other algae and skeletonized protozoans, suggest that the two episodes were quite distinct. Common causation appears unlikely, casting doubt on monolithic theories of mass extinction, whether periodic or not. Studies of mass extinction highlight a broader class of insights that palaeontologists can contribute to evolutionary biology: the evaluation of evolutionary change in the context of evolving Earth-surface environments.

Environmental Violence and Its Consequences

2015 ◽  
Vol 42 (5) ◽  
pp. 19-26
Author(s):  
Horacio de la Cueva Salcedo
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Changing Environments ◽  
Extinction Rates ◽  
Use Of Resources ◽  
Sixth Mass Extinction ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
Selection Of ◽  
Consequences Of Violence

Environmental changes happen all the time. Changing environments bring about selection of organisms, and there is no organism that does not modify its environment to make a living, survive, and reproduce. These changes are the main motors of evolution and, consequently, the main cause of biodiversity. Environmental violence—unsustainable use and extraction of natural resources—is the way capitalist economies exploit nature. The extinction rates associated with the current unsustainable use of resources are sufficient to assume that we are experiencing a sixth mass extinction event. The rate at which humans are transforming the environment leaves no time for evolutionary adaptation. We need to reduce environmental violence for life to maintain its normal processes. Without knowledge of nature and the consequences of violence against nature, we will become another of the planet’s extinct species. Los cambios ambientales ocurren todo el tiempo. Los ambientes cambiantes propician la selección de organismos y no hay organismo que no modifique su ambiente para subsistir y reproducirse. Estos cambios son los principales motores de la evolución y por lo tanto la causa principal de la biodiversidad. La violencia ambiental—el uso y la extracción insostenibles de los recursos naturales—es la manera en que las economías capitalistas explotan la naturaleza. Las tasas de extinción asociadas con el uso insostenible de los recursos son suficientes para considerar que estamos experimentando la sexta extinción masiva de especies. El ritmo al cual los seres humanos están transformando el ambiente no deja tiempo para la adaptación evolutiva. Necesitamos reducir la violencia ambiental para que la vida pueda mantener sus procesos normales. Sin el conocimiento de la naturaleza y de las consecuencias de la violencia contra ella, nos convertiremos en otra de las especies extintas de nuestro planeta.

scholarly journals A paradoxical knowledge gap in science for critically endangered fishes and game fishes during the sixth mass extinction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christopher S. Guy ◽  
Tanner L. Cox ◽  
Jacob R. Williams ◽  
Colter D. Brown ◽  
Robert W. Eckelbecker ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Species Conservation ◽  
Marine Species ◽  
Scientific Productivity ◽  
Scientific Output ◽  
Critically Endangered ◽  
Extinction Rate ◽  
Sixth Mass Extinction ◽  
Game Fish ◽  
The Difference

AbstractDespite unprecedented scientific productivity, Earth is undergoing a sixth mass extinction. The disconnect between scientific output and species conservation may be related to scientists studying the wrong species. Given fishes have a high extinction rate, we assessed the paradox between scientific productivity and science needed for conservation by comparing scientific output created for critically endangered fishes and game fishes. We searched 197,866 articles (1964–2018) in 112 journals for articles on 460 critically endangered fishes, 297 game fishes, and 35 fishes classified as critically endangered and game fish—our analysis included freshwater and marine species. Only 3% of the articles in the final database were on critically endangered fishes; 82% of critically endangered fishes had zero articles. The difference between the number of articles on game fishes and critically endangered fishes increased temporally with more articles on game fishes during the extinction crisis. Countries with 10 or more critically endangered fishes averaged only 17 articles from 1964 to 2018. Countries with the most critically endangered fishes are most in need of science. More scientific knowledge is needed on critically endangered fishes to meet the challenges of conserving fishes during the sixth mass extinction.

Effects of the early Toarcian Oceanic Anoxic Event on ichthyosaur body size and faunal composition in the Southwest German Basin

Paleobiology ◽  
2015 ◽  
Vol 42 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Erin E. Maxwell ◽  
Peggy Vincent
Keyword(s):  
Body Size ◽  
Environmental Changes ◽  
Marine Invertebrates ◽  
Abundant Species ◽  
Extinction Rate ◽  
Oceanic Anoxic Event ◽  
Environmental Perturbations ◽  
Anoxic Event ◽  
Posidonia Shale ◽  
German Basin

AbstractThe Early Jurassic Toarcian Oceanic Anoxic Event is considered one of the most dramatic environmental perturbations of the Mesozoic. An elevated extinction rate among marine invertebrates accompanied rapid environmental changes, but effects on large vertebrates are less understood. We examined changes in ichthyosaur body size in the Posidonia Shale of the Southwest German Basin spanning the extinction interval to assess how environmental changes and biotic crisis among prey species affected large reptiles. We report no species-level extinction among the ichthyosaurs coinciding with peak invertebrate extinction. Large ichthyosaurs were absent from the fauna during the extinction interval, but became more abundant in the immediate aftermath.Stenopterygius quadriscissus, the most abundant species during the extinction interval, increased in body size after the biotic event. Rapid invasion by large taxa occurred immediately following the extinction event at the end of the first ammonite zone of the early Toarcian. Greater mobility permitting exploitation of ephemeral resources and opportunistic feeding behavior may minimize the impacts of environmental change on large vertebrates.

Geographic variation in turnover and recovery from the Late Ordovician mass extinction

Paleobiology ◽  
2007 ◽  
Vol 33 (3) ◽  
pp. 435-454 ◽  
Author(s):  
Andrew Z. Krug ◽  
Mark E. Patzkowsky
Keyword(s):  
Mass Extinction ◽  
Late Ordovician ◽  
Mass Extinctions ◽  
Climatic Fluctuations ◽  
Extinction Rates ◽  
Large Size ◽  
Extinction Event ◽  
Global Extinction ◽  
Rate Of Recovery ◽  
Extinction Events

AbstractUnderstanding what drives global diversity requires knowledge of the processes that control diversity and turnover at a variety of geographic and temporal scales. This is of particular importance in the study of mass extinctions, which have disproportionate effects on the global ecosystem and have been shown to vary geographically in extinction magnitude and rate of recovery.Here, we analyze regional diversity and turnover patterns for the paleocontinents of Laurentia, Baltica, and Avalonia spanning the Late Ordovician mass extinction and Early Silurian recovery. Using a database of genus occurrences for inarticulate and articulate brachiopods, bivalves, anthozoans, and trilobites, we show that sampling-standardized diversity trends differ for the three regions. Diversity rebounded to pre-extinction levels within 5 Myr in the paleocontinent of Laurentia, compared with 15 Myr or longer for Baltica and Avalonia. This increased rate of recovery in Laurentia was due to both lower Late Ordovician extinction rates and higher Early Silurian origination rates relative to the other continents. Using brachiopod data, we dissected the Rhuddanian recovery into genus origination and invasion. This analysis revealed that standing diversity in the Rhuddanian consisted of a higher proportion of invading taxa in Laurentia than in either Baltica or Avalonia. Removing invading genera from diversity counts caused Rhuddanian diversity to fall in Laurentia. However, Laurentian diversity still rebounded to pre-extinction levels within 10 Myr of the extinction event, indicating that genus origination rates were also higher in Laurentia than in either Baltica or Avalonia. Though brachiopod diversity in Laurentia was lower than in the higher-latitude continents prior to the extinction, increased immigration and genus origination rates made it the most diverse continent following the extinction. Higher rates of origination in Laurentia may be explained by its large size, paleogeographic location, and vast epicontinental seas. It is possible that the tropical position of Laurentia buffered it somewhat from the intense climatic fluctuations associated with the extinction event, reducing extinction intensities and allowing for a more rapid rebound in this region. Hypotheses explaining the increased levels of invasion into Laurentia remain largely untested and require further scrutiny. Nevertheless, the Late Ordovician mass extinction joins the Late Permian and end-Cretaceous as global extinction events displaying an underlying spatial complexity.

scholarly journals Adjusting global extinction rates to account for taxonomic susceptibility

Paleobiology ◽  
2008 ◽  
Vol 34 (4) ◽  
pp. 434-455 ◽  
Author(s):  
Steve C. Wang ◽  
Andrew M. Bush
Keyword(s):  
Inverse Correlation ◽  
Volcanic Eruptions ◽  
Time Interval ◽  
Extinction Rate ◽  
Mass Extinctions ◽  
Sea Level Changes ◽  
Marine Fauna ◽  
Extinction Rates ◽  
Global Extinction ◽  
Taxonomic Groups

Studies of extinction in the fossil record commonly involve comparisons of taxonomic extinction rates, often expressed as the percentage of taxa (e.g., families or genera) going extinct in a time interval. Such extinction rates may be influenced by factors that do not reflect the intrinsic severity of an extinction trigger. Two identical triggering events (e.g., bolide impacts, sea level changes, volcanic eruptions) could lead to different taxonomic extinction rates depending on factors specific to the time interval in which they occur, such as the susceptibility of the fauna or flora to extinction, the stability of food webs, the positions of the continents, and so on. Thus, it is possible for an extinction event with a higher taxonomic extinction rate to be caused by an intrinsically less severe trigger, compared to an event with a lower taxonomic extinction rate.Here, we isolate the effects of taxonomic susceptibility on extinction rates. Specifically, we quantify the extent to which the taxonomic extinction rate in a substage is elevated or depressed by the vulnerability to extinction of classes extant in that substage. Using a logistic regression model, we estimate that the taxonomic susceptibility of marine fauna to extinction has generally declined through the Phanerozoic, and we adjust the observed extinction rate in each substage to estimate the intrinsic extinction severity more accurately. We find that mass extinctions do not generally occur during intervals of unusually high susceptibility, although susceptibility sometimes increases in post-extinction recovery intervals. Furthermore, the susceptibility of specific animal classes to extinction is generally similar in times of background and mass extinction, providing no evidence for differing regimes of extinction selectivity. Finally, we find an inverse correlation between extinction rate within substages and the evenness of diversity of major taxonomic groups, but further analyses indicate that low evenness itself does not cause high rates of extinction.

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