An analysis of the impacts of Cretaceous oceanic anoxic events on global molluscan diversity dynamics

Paleobiology ◽  
2019 ◽  
Vol 45 (02) ◽  
pp. 280-295 ◽  
Author(s):  
Nicholas A. Freymueller ◽  
Jason R. Moore ◽  
Corinne E. Myers
Keyword(s):  
Linear Models ◽  
Species Level ◽  
Extinction Rate ◽  
Extinction Rates ◽  
Anoxic Events ◽  
Molluscan Diversity ◽  
Extinction Events ◽  
Diversity Dynamics ◽  
The Impact ◽  
Stage Boundaries

AbstractOceanic anoxic events (OAEs) are contemporaneous with 11 of the 18 largest Phanerozoic extinction events, but the magnitude and selectivity of their paleoecological impact remains disputed. OAEs are associated with abrupt, rapid warming and increased CO2flux to the atmosphere; thus, insights from this study may clarify the impact of current anthropogenic climate change on the biosphere. We investigated the influence of the Late Cretaceous Bonarelli event (OAE2; Cenomanian/Turonian stage boundary; ~94 Ma) on generic- and species-level molluscan diversity, extinction rates, and ecological turnover. Cenomanian/Turonian results were compared with changes across all Cretaceous stage boundaries, some of which are coincident with less severe OAEs. We found increased generic turnover, but not species-level turnover, associated with several Cretaceous OAEs. The absence of a species-level pattern may reflect species occurrence data that are too temporally coarse to robustly detect patterns. Five hypotheses of ecological selectivity relating anoxia to survivorship were tested across stage boundaries with respect to faunality, mobility, and diet using generalized linear models. Interestingly, benthic taxa were consistently selected against throughout the Cretaceous regardless of the presence or absence of OAEs. These results suggest that: (1) the Cenomanian/Turonian boundary (OAE2) was associated with a decline in molluscan diversity and increase in extinction rate that were significantly more severe than Cretaceous background levels; and (2) no differential ecological selectivity was associated with OAE-related diversity declines among the variables tested here.

THE IMPACT OF OAE2 ON GLOBAL MOLLUSCAN DIVERSITY DYNAMICS

2016 ◽  
Author(s):  
Nicholas Freymueller ◽  
◽  
Corinne Myers
Keyword(s):  
Molluscan Diversity ◽  
Diversity Dynamics ◽  
The Impact

Taxonomic survivorship curves and Van Valen's Law

Paleobiology ◽  
1975 ◽  
Vol 1 (1) ◽  
pp. 82-96 ◽  
Author(s):  
David M. Raup
Keyword(s):  
Fossil Record ◽  
Species Level ◽  
Extinction Rate ◽  
Survivorship Analysis ◽  
Survivorship Curve ◽  
Extinction Rates ◽  
Higher Taxa ◽  
Total Life ◽  
Adaptive Zone

As Van Valen has demonstrated, the taxonomic survivorship curve is a valuable means of investigating extinction rates in the fossil record. He suggested that within an adaptive zone, related taxa display stochastically constant and equal extinction rates. Such a condition is evidenced by straight survivorship curves for species and higher taxa. Van Valen's methods of survivorship analysis can be improved upon and several suggestions are presented. With proper manipulation of data, it is possible to pool the information from extinct and living taxa to produce a single survivorship curve and therefore a single estimate of extinction rate. If extinction rate is constant at the species level (producing a straight survivorship curve), higher taxa in the same group should be expected to have convex survivorship curves. The constancy of extinction rates (here termed Van Valen's Law) can and should be tested rigorously. Several methods are available, of which the Total Life method of Epstein is particularly effective.

scholarly journals Diversification of African Rainforest Restricted Clades: Piptostigmateae and Annickieae (Annonaceae)

Diversity ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 227 ◽  
Author(s):  
Baptiste Brée ◽  
Andrew J. Helmstetter ◽  
Kévin Bethune ◽  
Jean-Paul Ghogue ◽  
Bonaventure Sonké ◽  
...  
Keyword(s):  
East Africa ◽  
East African ◽  
African Species ◽  
Extinction Rates ◽  
West Central ◽  
History Of ◽  
Best Fitting ◽  
The One ◽  
Extinction Events ◽  
The Impact

African rainforests (ARFs) are species rich and occur in two main rainforest blocks: West/Central and East Africa. This diversity is suggested to be the result of recent diversification, high extinction rates and multiple vicariance events between west/central and East African forests. We reconstructed the diversification history of two subtribes (Annickieae and Piptostigmateae) from the ecologically dominant and diverse tropical rainforest plant family Annonaceae. Both tribes contain endemic taxa in the rainforests of West/Central and East Africa. Using a dated molecular phylogeny based on 32 nuclear markers, we estimated the timing of the origin of East African species. We then undertook several diversification analyses focusing on Piptostigmateae to infer variation in speciation and extinction rates, and test the impact of extinction events. Speciation in both tribes dated to the Pliocene and Pleistocene. In particular, Piptostigma (13 species) diversified mainly during the Pleistocene, representing one of the few examples of Pleistocene speciation in an African tree genus. Our results also provide evidence of an ARF fragmentation at the mid-Miocene linked to climatic changes across the region. Overall, our results suggest that continental-wide forest fragmentation during the Neogene (23.03–2.58 Myr), and potentially during the Pliocene, led to one or possibly two vicariance events within the ARF clade Piptostigmateae, in line with other studies. Among those tested, the best fitting diversification model was the one with an exponential speciation rate and no extinction. We did not detect any evidence of mass extinction events. This study gives weight to the idea that the ARF might not have been so negatively impacted by extinction during the Neogene, and that speciation mainly took place during the Pliocene and Pleistocene.

Habitat breadth and geographic range predict diversity dynamics in marine Mesozoic bivalves

Paleobiology ◽  
10.1666/12047 ◽  
2013 ◽  
Vol 39 (3) ◽  
pp. 360-372 ◽  
Author(s):  
Sabine Nürnberg ◽  
Martin Aberhan
Keyword(s):  
Linear Models ◽  
Extinction Risk ◽  
Geographic Range ◽  
Independent Effect ◽  
Data Sets ◽  
Mass Extinctions ◽  
Mean Values ◽  
Extinction Rates ◽  
Habitat Breadth ◽  
Diversity Dynamics

Numerous environmental and intrinsic biotic factors have been sought to explain patterns in diversity and turnover. Using taxonomically vetted and sampling-standardized data sets of more than 50,000 taxonomic occurrences in the Paleobiology Database (PaleoDB) we tested whether habitat breadth predicts genus durations and diversity dynamics of marine Mesozoic bivalves, and whether this effect is independent of the well-known positive relationship between geographic range and longevity. We defined the habitat breadth of a genus as a function of its realized ranges in water depth, substrate type, and grain size of the substrate. Our analysis showed that mean values of extinction and origination rates are significantly higher for narrowly adapted genera compared to broadly adapted genera, with differences being evident in all analyzed stratigraphic intervals. Linear models showed that both geographic range and habitat breadth have an independent effect on genus durations and on diversity dynamics. These results reaffirm the role of geographic range and furthermore suggest that habitat breadth is an equally important key predictor of extinction risk and origination probability in Mesozoic marine bivalves. Habitat generalists, regardless of their geographic range, are generally less prone to extinction. Conversely, widely distributed genera that are more specialized may be more endangered than one would expect from their geographic range alone. Extinction rates tend to be higher for specialized genera in both background and mass extinctions, suggesting that wide habitat breadth universally buffers against extinction. The trajectories of origination rates through time differ from those of extinction rates. Whereas there is no pronounced ecological selectivity in origination in the Triassic and most of the Jurassic, Cretaceous origination rates are higher for specialized genera. This may best be explained by diversity-dependence. When diversity levels reach a critical point a further increase in diversity is achieved by elevated origination rates of more specialized forms.

A kinetic model of Phanerozoic taxonomic diversity II. Early Phanerozoic families and multiple equilibria

Paleobiology ◽  
1979 ◽  
Vol 5 (3) ◽  
pp. 222-251 ◽  
Author(s):  
J. John Sepkoski
Keyword(s):  
Kinetic Model ◽  
Multiple Equilibria ◽  
Dynamic Equilibrium ◽  
Taxonomic Diversity ◽  
Extinction Rate ◽  
Two Phase ◽  
Extinction Rates ◽  
History Of ◽  
Extinction Events ◽  
Middle And Late Cambrian

The kinetic model of taxonomic diversity predicts that the long-term diversification of taxa within any large and essentially closed ecological system should approximate a logistic process controlled by changes in origination and extinction rates with changing numbers of taxa. This model is tested with a new compilation of numbers of metazoan families known from Paleozoic stages (including stage-level subdivisions of the Cambrian). These data indicate the occurrence of two intervals of logistic diversification within the Paleozoic. The first interval, spanning the Vendian and Cambrian, includes an approximately exponential increase in families across the Precambrian-Cambrian Boundary and a “pseudo-equilibrium” through the Middle and Late Cambrian, caused by diversity-dependent decrease in origination rate and increase in extinction rate. The second interval begins with a rapid re-diversification in the Ordovician, which leads to a tripling of familial diversity during a span of 50 Myr; by the end of the Ordovician diversity attains a new dynamic equilibrium that is maintained, except for several extinction events, for nearly 200 Myr until near the end of the Paleozoic. A “two-phase” kinetic model is constructed to describe this heterogeneous pattern of early Phanerozoic diversification. The model adequately describes the “multiple equilibria,” the asymmetrical history of the “Cambrian fauna,” the extremely slow initial diversification of the later “Paleozoic fauna,” and the combined patterns of origination and extinction in both faunas. It is suggested that this entire pattern of diversification reflects the early success of ecologically generalized taxa and their later replacement by more specialized taxa.

Temporal variation in extinction risk and temporal scaling of extinction metrics

Paleobiology ◽  
1994 ◽  
Vol 20 (4) ◽  
pp. 424-444 ◽  
Author(s):  
Mike Foote
Keyword(s):  
Extinction Risk ◽  
Interval Length ◽  
Extinction Rate ◽  
Wide Range ◽  
Extinction Model ◽  
Definition Of ◽  
Extinction Events ◽  
The Relationship ◽  
Very High ◽  
Stage Boundaries

Many areas of paleobiological research require reliable extinction metrics. Branching-and-extinction simulations and data on Phanerozoic marine families and genera are used to investigate the relationship between interval length and commonly used extinction metrics. Normalization of extinction metrics for interval length is problematic, even when interval length is known without error, because normalization implicitly assumes some model of variation in extinction risk within an interval. If extinction risk within an interval were constant, or if it varied but played no role in the definition of stratigraphic intervals, then Van Valen's time-normalized extinction metric would provide a measure of average extinction risk that is effectively unbiased by interval length. When extinction risk varies greatly within an interval and interval boundaries are drawn at times of heavy extinction, extinction metrics that normalize for interval length are negatively correlated with interval length. Despite its intuitive appeal, the per-taxon extinction rate (proportional extinction per million years) is biased by interval length under a wide range of extinction models.Empirically, time-normalized extinction metrics for Phanerozoic families and genera are negatively correlated with interval length. This is consistent with an extinction model in which many times of very low risk are punctuated by a few times of very high risk which in turn determine stage boundaries. Origination and extinction patterns are similar, but origination intensity varies less among stages than extinction intensity. This observation has at least two plausible explanations: that origination episodes are more protracted than extinction episodes, and that biologic groups do not respond in unison to origination opportunities the way they seem to respond during extinction events. For families and genera, there is enough variation in extinction intensity among stages that stage length can be ignored when studying certain extinction patterns over the entire Phanerozoic.

scholarly journals An examination of the impact of Olson’s extinction on tetrapods from Texas

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4767 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Species Richness ◽  
Stochastic Approach ◽  
Species Level ◽  
Single Event ◽  
Extinction Rates ◽  
Definition Of ◽  
Land Vertebrate ◽  
The Impact ◽  
Kungurian Stage ◽  
Substantial Drop

It has been suggested that a transition between a pelycosaurian-grade synapsid dominated fauna of the Cisuralian (early Permian) and the therapsid dominated fauna of the Guadalupian (middle Permian) was accompanied by, and possibly driven by, a mass extinction dubbed Olson’s Extinction. However, this interpretation of the record has recently been criticised as being a result of inappropriate time-binning strategies: calculating species richness within international stages or substages combines extinctions occurring throughout the late Kungurian stage into a single event. To address this criticism, I examine the best record available for the time of the extinction, the tetrapod-bearing formations of Texas, at a finer stratigraphic scale than those previously employed. Species richness is calculated using four different time-binning schemes: the traditional Land Vertebrate Faunachrons (LVFs); a re-definition of the LVFs using constrained cluster analysis; individual formations treated as time bins; and a stochastic approach assigning specimens to half-million-year bins. Diversity is calculated at the genus and species level, both with and without subsampling, and extinction rates are also inferred. Under all time-binning schemes, both at the genus and species level, a substantial drop in diversity occurs during the Redtankian LVF. Extinction rates are raised above background rates throughout this time, but the biggest peak occurs in the Choza Formation (uppermost Redtankian), coinciding with the disappearance from the fossil record of several of amphibian clades. This study, carried out at a finer stratigraphic scale than previous examinations, indicates that Olson’s Extinction is not an artefact of the method used to bin data by time in previous analyses.

scholarly journals Decline in extinction rates and scale invariance in the fossil record

Paleobiology ◽  
1999 ◽  
Vol 25 (4) ◽  
pp. 434-439 ◽  
Author(s):  
M. E. J. Newman ◽  
Gunther J. Eble
Keyword(s):  
Power Spectrum ◽  
Power Law ◽  
Fossil Record ◽  
Scale Invariance ◽  
Evolutionary Dynamics ◽  
Extinction Rate ◽  
Extinction Rates ◽  
Self Organized ◽  
Critical Theories ◽  
Extinction Events

We show that the decline in the extinction rate during the Phanerozoic can be accurately described by a logarithmic fit to the cumulative total extinction. This implies that extinction intensity is falling off approximately as the reciprocal of time. We demonstrate that this observation alone is sufficient to explain the existence of the proposed power-law forms in the distribution of the sizes of extinction events and in the power spectrum of Phanerozoic extinction, results that previously have been explained by appealing to self-organized critical theories of evolutionary dynamics.

Origination and extinction components of taxonomic diversity: Paleozoic and post-Paleozoic dynamics

Paleobiology ◽  
2000 ◽  
Vol 26 (4) ◽  
pp. 578-605 ◽  
Author(s):  
Mike Foote
Keyword(s):  
Taxonomic Diversity ◽  
Extinction Rate ◽  
Strongly Correlated ◽  
Marine Animals ◽  
Extinction Rates ◽  
Higher Taxa ◽  
Diversity Dynamics ◽  
Secular Increase ◽  
Weak Tendency

Changes in genus diversity within higher taxa of marine animals on the temporal scale of a few million years are more strongly correlated with changes in extinction rate than with changes in origination rate during the Paleozoic. After the Paleozoic the relative roles of origination and extinction in diversity dynamics are reversed. Metazoa as well as individual higher taxa shift from one mode of diversity dynamics to the other. The magnitude of taxonomic rates, the relative variance of origination and extinction rates, and the presence or absence of a long-term secular increase in diversity all fail to account for the shift in importance of origination and extinction in diversity changes. Origination and extinction rates both tend to be diversity-dependent, but different modes of diversity-dependence may contribute to the change in diversity dynamics from the Paleozoic to the post-Paleozoic. During the Paleozoic, there is a weak tendency for extinction rates to be more diversity-dependent than origination rates, whereas after the Paleozoic the two rates are about equally diversity-dependent on average.

scholarly journals Socio-economic consequences of mental distress: quantifying the impact of self-reported mental distress on the days of incapacity to work and medical costs in a two-year period: a longitudinal study in Germany

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Gerhard Müller ◽  
Manuela Bombana ◽  
Monika Heinzel-Gutenbrenner ◽  
Nikolaus Kleindienst ◽  
Martin Bohus ◽  
...  
Keyword(s):  
Mental Disorders ◽  
Mental Distress ◽  
Linear Models ◽  
Longitudinal Research ◽  
Depression Scale ◽  
Routine Data ◽  
Medical Costs ◽  
First Year ◽  
Second Year ◽  
The Impact

Abstract Background Mental disorders are related to high individual suffering and significant socio-economic burdens. However, it remains unclear to what extent self-reported mental distress is related to individuals’ days of incapacity to work and their medical costs. This study aims to investigate the impact of self-reported mental distress for specific and non-specific days of incapacity to work and specific and non-specific medical costs over a two-year span. Method Within a longitudinal research design, 2287 study participants’ mental distress was assessed using the Hospital Anxiety and Depression Scale (HADS). HADS scores were included as predictors in generalized linear models with a Tweedie distribution with log link function to predict participants’ days of incapacity to work and medical costs retrieved from their health insurance routine data during the following two-year period. Results Current mental distress was found to be significantly related to the number of specific days absent from work and medical costs. Compared to participants classified as no cases by the HADS (2.6 days), severe case participants showed 27.3-times as many specific days of incapacity to work in the first year (72 days) and 10.3-times as many days in the second year (44 days), and resulted in 11.4-times more medical costs in the first year (2272 EUR) and 6.2-times more in the second year (1319 EUR). The relationship of mental distress to non-specific days of incapacity to work and non-specific medical costs was also significant, but mainly driven from specific absent days and specific medical costs. Our results also indicate that the prevalence of presenteeism is considerably high: 42% of individuals continued to go to work despite severe mental distress. Conclusions Our results show that self-reported mental distress, assessed by the HADS, is highly related to the days of incapacity to work and medical costs in the two-year period. Reducing mental distress by improving preventive structures for at-risk populations and increasing access to evidence-based treatments for individuals with mental disorders might, therefore, pay for itself and could help to reduce public costs.

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