scholarly journals Speciation rates of subviral pathogens of angiosperms abruptly decreased at the Cretaceous–Paleogene boundary

2019 ◽  
Author(s):  
Piotr Bajdek
Keyword(s):  
Mass Extinction ◽  
Continental Drift ◽  
Time Calibration ◽  
Drift Theory ◽  
Speciation Rates ◽  
History Of ◽  
Probable Impact ◽  
Mass Extinction Event ◽  
Extinction Events ◽  
First Time

Biogeographic distribution of infected plants and the continental drift theory allow a time calibration of the phylogenetic tree of Pospiviroidae. Viroids evolved in the late Early Cretaceous shortly after the appearance of angiosperms, which constitute their only known hosts. No decline in the estimated speciation rates of Pospiviroidae is observed during the Late Cretaceous but they abruptly decreased at the Cretaceous–Paleogene boundary. However, an adaptive radiation of Pospiviroidae which occurred in the late Paleocene may reflect a recovery from the K–Pg mass extinction. The evolutionary history of viroids has been in part shaped by radiation and extinction events of angiosperms. Herein, for the first time I show the probable impact of a mass extinction event on the speciation rates of subviral pathogens, which are the simplest known lifeforms.

scholarly journals Speciation rates of subviral pathogens of angiosperms abruptly decreased at the Cretaceous–Paleogene boundary

2019 ◽  
Author(s):  
Piotr Bajdek
Keyword(s):  
Mass Extinction ◽  
Continental Drift ◽  
Time Calibration ◽  
Drift Theory ◽  
Speciation Rates ◽  
History Of ◽  
Probable Impact ◽  
Mass Extinction Event ◽  
Extinction Events ◽  
First Time

Biogeographic distribution of infected plants and the continental drift theory allow a time calibration of the phylogenetic tree of Pospiviroidae. Viroids evolved in the late Early Cretaceous shortly after the appearance of angiosperms, which constitute their only known hosts. No decline in the estimated speciation rates of Pospiviroidae is observed during the Late Cretaceous but they abruptly decreased at the Cretaceous–Paleogene boundary. However, an adaptive radiation of Pospiviroidae which occurred in the late Paleocene may reflect a recovery from the K–Pg mass extinction. The evolutionary history of viroids has been in part shaped by radiation and extinction events of angiosperms. Herein, for the first time I show the probable impact of a mass extinction event on the speciation rates of subviral pathogens, which are the simplest known lifeforms.

scholarly journals Divergence rates of subviral pathogens of angiosperms abruptly decreased at the Cretaceous-Paleogene boundary

2019 ◽  
Vol 4 ◽  
pp. 89-101 ◽  
Author(s):  
Piotr Bajdek
Keyword(s):  
Mass Extinction ◽  
Continental Drift ◽  
Time Calibration ◽  
Extinction Event ◽  
Drift Theory ◽  
History Of ◽  
Probable Impact ◽  
Mass Extinction Event ◽  
Extinction Events ◽  
First Time

Biogeographic distribution of infected plants and the continental drift theory allow a tentative time calibration of the phylogenetic tree of Pospiviroidae. Hypothetically, viroids evolved in the late Early Cretaceous shortly after the appearance of angiosperms, which constitute their only known hosts. No decline in the estimated divergence rates of Pospiviroidae is observed during the Late Cretaceous but it appears that they abruptly decreased at the Cretaceous-Paleogene boundary. However, an adaptive radiation of Pospiviroidae which occurred in the late Paleocene may reflect a recovery from the Cretaceous-Paleogene (K–Pg) mass extinction. It seems that the evolutionary history of viroids has been in part shaped by radiation and extinction events of angiosperms. Herein, for the first time I show the probable impact of a mass extinction event on the divergence rates of subviral pathogens, which are the simplest known “lifeforms”.

scholarly journals Dinosaurs in decline tens of millions of years before their final extinction

2016 ◽  
Vol 113 (18) ◽  
pp. 5036-5040 ◽  
Author(s):  
Manabu Sakamoto ◽  
Michael J. Benton ◽  
Chris Venditti
Keyword(s):  
Mass Extinction ◽  
Marked Reduction ◽  
Evolutionary Dynamics ◽  
General Pattern ◽  
Extinction Rate ◽  
Catastrophic Event ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
First Time

Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

scholarly journals Mass extinction in tetraodontiform fishes linked to the Palaeocene–Eocene thermal maximum

2017 ◽  
Vol 284 (1866) ◽  
pp. 20171771 ◽  
Author(s):  
Dahiana Arcila ◽  
James C. Tyler
Keyword(s):  
Mass Extinction ◽  
Reef Fishes ◽  
Morphological Data ◽  
Fossil Species ◽  
Thermal Maximum ◽  
Extant Species ◽  
Homogeneous Models ◽  
Speciation Rates ◽  
Mass Extinction Event ◽  
Lineage Diversification

Integrative evolutionary analyses based upon fossil and extant species provide a powerful approach for understanding past diversification events and for assessing the tempo of evolution across the Tree of Life. Herein, we demonstrate the importance of integrating fossil and extant species for inferring patterns of lineage diversification that would otherwise be masked in analyses that examine only one source of evidence. We infer the phylogeny and macroevolutionary history of the Tetraodontiformes (triggerfishes, pufferfishes and allies), a group with one of the most extensive fossil records among fishes. Our analyses combine molecular and morphological data, based on an expanded matrix that adds newly coded fossil species and character states. Beyond confidently resolving the relationships and divergence times of tetraodontiforms, our diversification analyses detect a major mass-extinction event during the Palaeocene–Eocene Thermal Maximum (PETM), followed by a marked increase in speciation rates. This pattern is consistently obtained when fossil and extant species are integrated, whereas examination of the fossil occurrences alone failed to detect major diversification changes during the PETM. When taking into account non-homogeneous models, our analyses also detect a rapid lineage diversification increase in one of the groups (tetraodontoids) during the middle Miocene, which is considered a key period in the evolution of reef fishes associated with trophic changes and ecological opportunity. In summary, our analyses show distinct diversification dynamics estimated from phylogenies and the fossil record, suggesting that different episodes shaped the evolution of tetraodontiforms during the Cenozoic.

scholarly journals Post-Cretaceous bursts of evolution along the benthic-pelagic axis in marine fishes

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182010 ◽  
Author(s):  
Emanuell Ribeiro ◽  
Aaron M. Davis ◽  
Rafael A. Rivero-Vega ◽  
Guillermo Ortí ◽  
Ricardo Betancur-R
Keyword(s):  
Morphological Variation ◽  
Mass Extinction ◽  
Marine Fishes ◽  
Ecological Opportunity ◽  
Pelagic Habitat ◽  
History Of ◽  
Evolutionary Radiations ◽  
Extinction Events ◽  
Mass Extinction Events ◽  
Lineage Diversification

Ecological opportunity arising in the aftermath of mass extinction events is thought to be a powerful driver of evolutionary radiations. Here, we assessed how the wake of the Cretaceous–Palaeogene (K-Pg) mass extinction shaped diversification dynamics in a clade of mostly marine fishes (Carangaria), which comprises a disparate array of benthic and pelagic dwellers including some of the most astonishing fish forms (e.g. flatfishes, billfishes, remoras, archerfishes). Analyses of lineage diversification show time-heterogeneous rates of lineage diversification in carangarians, with highest rates reached during the Palaeocene. Likewise, a remarkable proportion of Carangaria's morphological variation originated early in the history of the group and in tandem with a marked incidence of habitat shifts. Taken together, these results suggest that all major lineages and body plans in Carangaria originated in an early burst shortly after the K-Pg mass extinction, which ultimately allowed the occupation of newly released niches along the benthic-pelagic habitat axis.

Beyond the Big Five: Extinctions as Experiments in the History of Life

2008 ◽  
Vol 14 ◽  
pp. 249-270 ◽  
Author(s):  
Rowan Lockwood
Keyword(s):  
Mass Extinction ◽  
Interdisciplinary Approach ◽  
Future Research ◽  
Past Century ◽  
Natural Experiments ◽  
Evolutionary Patterns ◽  
The Past ◽  
Research Areas ◽  
History Of ◽  
Extinction Events

The past century has witnessed a number of significant breakthroughs in the study of extinction in the fossil record, from the discovery of a bolide impact as the probable cause of the end-Cretaceous (K/T) mass extinction to the designation of the “Big 5” mass extinction events. Here, I summarize the major themes that have emerged from the past thirty years of extinction research and highlight a number of promising directions for future research. These directions explore a central theme—the evolutionary consequences of extinction— and focus on three broad research areas: the effects of selectivity, the importance of recovery intervals, and the influence of spatial patterns. Examples of topics explored include the role that trait variation plays in survivorship, the comparative effects of extinctions of varying magnitudes on evolutionary patterns, the re-establishment of macroevolutionary patterns in the aftermath of extinction, and the extent to which spatial autocorrelation affects extinction patterns. These topics can be approached by viewing extinctions as repeated natural experiments in the history of life and developing hypotheses to explicitly test across multiple events. Exploring the effects of extinction also requires an interdisciplinary approach, applying evolutionary, ecological, geochronological, geochemical, tectonic, and paleoclimatic tools to both extinction and recovery intervals.

Testing for a mass extinction without selecting taxa

Paleobiology ◽  
2000 ◽  
Vol 26 (4) ◽  
pp. 647-650 ◽  
Author(s):  
Andrew R. Solow ◽  
Woollcott K. Smith
Keyword(s):  
Statistical Inference ◽  
Mass Extinction ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
Extinction Events ◽  
Mass Extinction Events ◽  
Stratigraphic Height ◽  
Selection Of

Statistical inference about mass extinction events is commonly based on the pattern of fossil finds among a group of taxa. An important issue for existing methods is the selection of taxa for inclusion in the analysis. A common approach is to select taxa on the basis of the stratigraphic height of their uppermost finds. This approach creates a bias in favor of detecting a mass extinction event. This paper describes and illustrates an approach that avoids this problem.

Astronomical calibration of paleoclimatic and planktic foraminiferal events of the Cretaceous-Paleogene transition at Zumaia, Spain

2021 ◽  
Author(s):  
Vicente Gilabert ◽  
Sietske J. Batenburg ◽  
Ignacio Arenillas ◽  
José A. Arz
Keyword(s):  
Mass Extinction ◽  
Deccan Traps ◽  
Deccan Volcanism ◽  
Extinction Event ◽  
First Occurrence ◽  
Mass Extinction Event ◽  
Environmental Events ◽  
Chicxulub Impact ◽  
First Time ◽  
Intense Debate

<p>The main trigger for the Cretaceous/Paleogene boundary (KPB) mass extinction is still subject of intense debate. The co-occurrence of the Chicxulub impact (Yucatan, Mexico) and massive Deccan Traps volcanism (India) during Chron C29r hinders disentangling their climatic and environmental effects. Unravelling the influence of Deccan volcanism on the KPB extinction and other Maastrichtian and Danian perturbations requires more accurate age calibrations and duration estimates of biotic and climatic events. Here we integrate existing astrochronologies of the Zumaia section, allowing us to produce a refined cyclostratigraphic calibration of the main planktic foraminiferal and paleoclimatic events recorded across the KPB in the well-know Zumaia section (NW, Spain).</p><p>At Zumaia, the KPB is marked by a ~8 cm-thick dark clay bed, with low values of %CaCO<sub>3</sub> and δ<sup>13</sup>C. The Chicxulub ejecta-rich airfall layer has been identified at the base of the dark clay bed, but it is partially masked within a 1–2 cm-thick diagenetic calcitic layer. At Zumaia, the KPB has been astronomically calibrated at 66 Ma (compatible with radioisotopic ages), and the duration of dark clay bed is estimated at ~10 kyr. The first appearances (FA) of the Danian planktic foraminiferal index-species <em>Parvularugoglobigerina longiapertura</em>, <em>Parvularugoglobigerina eugubina</em>, <em>Eoglobigerina simplicissima</em>, <em>Parasubbotina pseudobulloides</em>, <em>Subbotina triloculinoides</em> and <em>Globanomalina compressa</em> have been orbitally tuned at Zumaia, to have occurred at 8, 30, 45, 70, 210, and 475 kyr after the KPB. Specimens of <em>Plummerita hantkeninoides</em> have been identified for the first time in the Maastrichtian of Zumaia, and its first occurrence is dated at ~100 kyr before the KPB. Based on d<sup>13</sup>C data, we have identified the late Maastrichtian Warming Event (LMWE), the early Danian Dan-C2 and the Lower-C29N events. Additionally, a bloom of the eutrophic/opportunist genus <em>Chiloguembelitria</em>, interpreted as a period of environmental stress, has also been recognized above and separate from the KPB clay bed. Besides the KPB, the main paleoclimatic/paleoenvironmental events have been astronomically calibrated at Zumaia as follows: the LMWE between 270 and 120 kyr before the KPB, the Dan-C2 event between 205 and 305 kyr after the KPB, the Lower-C29N event between 520 and 595 kyr after the KPB, and the Chiloguembelitria bloom between 100 and 305 kyr after the KPB. According to this chronology, we conclude that the LMWE and early Danian <em>Chiloguembelitria</em> bloom seems to coincide in time with major volcanic pulses of the Deccan Traps, unlike the Dan-C2 and Lower-C29N events, which appear to have been driven by orbital forcing. Regardless of the cause of climatic and environmental events, all these perturbations appear unrelated to the KPB mass extinction event. It supports the hypothesis that the influence of Deccan volcanism on planktic foraminiferal assemblages during the Maastrichtian and Danian was limited.</p>

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