scholarly journals The demise of dinosaurs and learned taste aversions: The biotic revenge hypothesis

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Michael Frederick ◽  
Gordon G. Gallup, Jr.
Keyword(s):  
Empirical Support ◽  
Volcanic Eruptions ◽  
Deccan Traps ◽  
Supporting Evidence ◽  
Asteroid Impact ◽  
Toxic Plants ◽  
Extinction Event ◽  
Impact Hypothesis ◽  
Multiple Causes

Numerous hypotheses have been advanced to explain the worldwide extinction event that led to the disappearance of the dinosaurs. There is considerable empirical support for the well-known asteroid impact hypothesis, and volcanic eruptions in the Deccan Traps have also been implicated. Increasingly, theories involving multiple causes are being considered, yet few of these consider how the cognitive and behavioral abilities of certain classes of animals may have differed in ways that allowed some to survive while others perished. Here we advance the hypothesis along with supporting evidence that the emergence of toxic plants coupled with an inability to form learned taste aversions may have contributed to the extinction of dinosaurs.

scholarly journals The demise of dinosaurs and learned taste aversions: The biotic revenge hypothesis

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Michael Frederick ◽  
Gordon G. Gallup, Jr.
Keyword(s):  
Empirical Support ◽  
Volcanic Eruptions ◽  
Deccan Traps ◽  
Supporting Evidence ◽  
Asteroid Impact ◽  
Toxic Plants ◽  
Extinction Event ◽  
Impact Hypothesis ◽  
Multiple Causes

Numerous hypotheses have been advanced to explain the worldwide extinction event that led to the disappearance of the dinosaurs. There is considerable empirical support for the well-known asteroid impact hypothesis, and volcanic eruptions in the Deccan Traps have also been implicated. Increasingly, theories involving multiple causes are being considered, yet few of these consider how the cognitive and behavioral abilities of certain classes of animals may have differed in ways that allowed some to survive while others perished. Here we advance the hypothesis along with supporting evidence that the emergence of toxic plants coupled with an inability to form learned taste aversions may have contributed to the extinction of dinosaurs.

Biography of the Earth

2021 ◽  
pp. 214-228
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Mass Extinction ◽  
Ice Sheets ◽  
Late Cenozoic ◽  
Ice Ages ◽  
Quaternary Period ◽  
Asteroid Impact ◽  
The Earth ◽  
Ecological Resources ◽  
Extinction Event ◽  
Cenozoic Era

The last era in the Phanerozoic Eon, the Cenozoic Era, is detailed in this chapter. The rise and radiation of the mammals occurred during Cenozoic after the devastation wrought by the Chicxulub Asteroid impact at the end of the Mesozoic Era. Ecological resources and niches vacated by the dinosaurs because of the mass extinction were filled by the mammals with concurrent developments in plants. Changes in climate and the mid-Miocene warming happened mid-era, then drying out and opening of grasslands followed by a plunge into ice ages and the Pleistocene extinction event. The late Cenozoic witnessed the development of humankind as the great ice sheets from the Pleistocene started to melt and the climate warm. The planet started to look similar to how it appears to humans today, and the current age of the Earth is the Cenozoic Era, Quaternary Period, Holocene Epoch, Meghalayan Age.

Vertebrate biodiversity of the Deccan volcanic province of India: A review

2012 ◽  
Vol 183 (6) ◽  
pp. 597-610 ◽  
Author(s):  
Guntupalli V.R. Prasad
Keyword(s):  
Volcanic Eruptions ◽  
Flood Basalt ◽  
Time Span ◽  
Deccan Traps ◽  
Mass Extinctions ◽  
Deccan Volcanic Province ◽  
Peninsular India ◽  
Volcanic Province ◽  
Detailed Review ◽  
Faunal Diversity

Abstract The Deccan Traps of peninsular India, representing one of the largest flood basalt eruptions on the earth's surface, have been a subject of intensive research in the last three decades because of the attributed link between the Deccan Traps and the Cretaceous-Tertiary boundary mass extinctions. In this context, the biota from the sedimentary beds intercalated with the volcanic flows and underlying the oldest volcanic flow are more important for understanding the faunal diversity and palaeobiogeography of India during the time span of volcanic eruptions. A detailed review of the vertebrate faunal diversity of the Deccan volcanic province is presented here.

Does Estrogen Protect Against Cognitive Aging in Women?

2007 ◽  
Vol 16 (5) ◽  
pp. 275-279 ◽  
Author(s):  
Barbara B. Sherwin
Keyword(s):  
Older Women ◽  
Verbal Memory ◽  
Cognitive Aging ◽  
Estrogen Therapy ◽  
Empirical Support ◽  
Supporting Evidence ◽  
Protective Effects ◽  
Neuroprotective Effects ◽  
Cross Sectional ◽  
Aging Women

Although there is evidence from randomized controlled trials that estrogen therapy protects against aspects of cognitive decline that occur with normal aging in women, findings from the Women's Health Initiative Memory Study and from some cross-sectional and longitudinal studies failed to find neuroprotective effects of estrogen in older women. There is growing empirical support for the critical-period hypothesis, formulated in the attempt to resolve these discrepancies. It holds that estrogen therapy has protective effects on verbal memory and on working memory only when it is initiated closely in time to menopause, whereas starting treatment many years following menopause does not protect and may even be harmful. Supporting evidence for this hypothesis from basic neuroscience and from animal and human studies is evaluated for its ability to explain the inconsistencies and to describe the conditions under which estrogen may protect cognitive function in aging women.

scholarly journals Influence of moral intelligence, principled leadership and trust on organisational citizenship behaviour

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Amos Engelbrecht ◽  
Karen Hendrikz
Keyword(s):  
Latent Variables ◽  
Structural Equation ◽  
Structural Model ◽  
Item Analysis ◽  
Empirical Support ◽  
Supporting Evidence ◽  
Measurement Scales ◽  
Trust In Leaders ◽  
Moral Intelligence ◽  
Indirect Relationship

Background: Organisational citizenship behaviour (OCB) plays a substantial role in individual and organisational performance.Aim: The aim of the study was to investigate how moral intelligence and principled leadership can influence trust in the leader and OCB.Setting: Data were collected from 300 employees from various organisations in South Africa. Purposive, non-probability sampling was used.Methods: A theoretical model and hypotheses were developed to explain the structural relationships among the latent variables. Data were analysed by means of item analysis and confirmatory factor analysis conducted via structural equation modelling (SEM).Results: High levels of reliability were found for the measurement scales. Good model fit was demonstrated for the measurement and structural models. Empirical support was found for the significant mediating effects of principled leadership and trust in leaders in the indirect relationship between moral intelligence and OCB. The Principled Leadership Scale (PLS) could be used in the selection or development of principled leaders to develop an ethical culture to combat the high levels of corruption that many organisations face. Principled leaders play a key role in creating an ethical and trusting work climate conducive for OCB.Conclusion: This study is the first to analyse the joint relationships among the specific latent variables in the structural model. Furthermore, the study provided the first supporting evidence for the concurrent validity of the newly developed PLS.

Mercury evidence from the Sino-Korean block for Emeishan volcanism during the Capitanian mass extinction

2018 ◽  
Vol 156 (06) ◽  
pp. 1105-1110 ◽  
Author(s):  
HYOSANG KWON ◽  
MUN GI KIM ◽  
YONG IL LEE
Keyword(s):  
Organic Carbon ◽  
Mass Extinction ◽  
Volcanic Eruptions ◽  
Global Carbon Cycle ◽  
Upper Permian ◽  
South China Block ◽  
Extinction Event ◽  
Tethys Ocean ◽  
Mass Extinction Event ◽  
Global Carbon

AbstractA prominent large negative δ13Corg excursion and a coeval notable spike in mercury (Hg)/total organic carbon ratio are observed in the middle–upper Permian Gohan Formation in central Korea, located in the eastern Sino-Korean block (SKB), which may represent the Capitanian mass extinction event. The SKB was separated from the South China block by the eastern Palaeo-Tethys Ocean. This finding from the SKB supports the widespread Hg loading to the environment emitted from the Emeishan volcanic eruptions in SW China. This study demonstrates that the Hg cycle was globally perturbed in association with global carbon cycle perturbation that occurred during the Capitanian Extinction.

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>

Late Devonian rugose corals and the Frasnian–Famennian crsis

1986 ◽  
Vol 23 (9) ◽  
pp. 1265-1287 ◽  
Author(s):  
J. E. Sorauf ◽  
A. E. H. Pedder
Keyword(s):  
Shallow Water ◽  
Gradual Increase ◽  
Rapid Decline ◽  
Ocean Temperature ◽  
Shallow Marine ◽  
Marine Benthos ◽  
Asteroid Impact ◽  
Rugose Corals ◽  
Extinction Event ◽  
Platform Carbonates

All well-dated occurrences of Upper Devonian septate corals (subclass Rugosa) are analyzed at species and higher taxonomic levels. Platform-dwelling corals are differentiated from the less numerous basin-dwelling corals.Through early and middle Frasnian time, evolution outpaced the extinction of rugose corals, so that late Frasnian faunas were more diverse than the earliest Frasnian faunas. This gradual increase of genera was terminated abruptly by an almost complete extinction of late Frasnian platform-dwelling Rugosa in uppermost gigas to lower Palmatolepis triangularis Zone time. None of the 151 species, and probably as few as two or three, at most five, of the 47 genera of late Frasnian shallow-water corals survived this event. The loss of coral biomass was equally devasting. Very few early Famennian platform-dwelling corals are known, although platform carbonates of this age were deposited in several regions. Platform faunas, comprising 66 species and 27 genera, reappeared in late Famennian time. These faunas were unrelated phylogenetically to known Frasnian faunas but were forerunners of shallow-water Carboniferous faunas.Basin-dwelling Rugosa were affected little by the late Frasnian extinction event: all 12 Frasnian genera survived it.Rugose coral data provide compelling evidence for a major late Frasnian extinction of shallow-marine benthos without suggesting a unique cause of it. The data are consistent with results expected of an asteroid impact or a rapid decline of ocean temperature, especially in regard to the very much higher survival rate among basin-dwelling corals. However, the data are not controlled by a sufficiently refined time scale to prove the geological instantaneity of such an event.

scholarly journals The longtime global climatic consequences modeling of the Chicxulub asteroid impact event

2021 ◽  
Vol 2090 (1) ◽  
pp. 012110
Author(s):  
V P Parkhomenko
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Surface Air Temperature ◽  
Volcanic Eruptions ◽  
Ocean Model ◽  
Surface Layers ◽  
Climatic Effects ◽  
Asteroid Impact ◽  
Earth’S Climate ◽  
Cretaceous Period

Abstract Studies indicate the mass death of a significant number of biological groups on Earth, in particular - dinosaurs, at the end of the Cretaceous period 66 million years ago. Currently, there are two main theories: large-scale volcanic eruptions and the asteroid impact that formed the Chicxulub crater (Mexico). The production of sulfur-containing gases from the Earth’s surface layers vapors during impact is considered a main source of climatic effects, as they form stratospheric sulfate aerosols that block sunlight and thus cool the Earth’s atmosphere and interfere with photosynthesis. It is presented an application of the 3-D coupled global hydrodynamic climate model of intermediate complexity, including ocean model, sea ice evolution model and energy - moisture balance atmosphere model to study this asteroid impact effects on the Earth’s climate. The model continents and ocean depths distribution corresponds to Cretaceous period. A series of calculations with different residence times and deposition times of the stratosphere aerosol have been carried out. It was found that, depending on the stratosphere aerosol time parameters, the global annual average surface air temperature decreased by 18°C - 27°C, remained below zero for 4 - 30 years, and a recovery time of more than 30 years was observed.

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