Population genetics and the Cretaceous extinction
نویسندگان
چکیده
منابع مشابه
Population extinction and the genetics of adaptation.
Theories of adaptation typically ignore the effect of environmental change on population size. But some environmental challenges--challenges to which populations must adapt--may depress absolute fitness below 1, causing populations to decline. Under this scenario, adaptation is a race; beneficial alleles that adapt a population to the new environment must sweep to high frequency before the popu...
متن کاملTerminal Cretaceous Extinction
A number of mechanisms have been proposed for the massive extinction of biota at the Cretaceous-Tertiary transition some 65 million years ago. Most of them were reviewed recently (I). Two additional mechanisms have been proposed, however, since that review was compiled-the "greenhouse" mechanism (2) and the Arctic spillover model (3). In the first of these. McLean has proposed that the large la...
متن کاملExtraterrestrial cause for the cretaceous-tertiary extinction.
Platinum metals are depleted in the earth's crust relative to their cosmic abundance; concentrations of these elements in deep-sea sediments may thus indicate influxes of extraterrestrial material. Deep-sea limestones exposed in Italy, Denmark, and New Zealand show iridium increases of about 30, 160, and 20 times, respectively, above the background level at precisely the time of the Cretaceous-...
متن کاملDecoupled plant and insect diversity after the end-Cretaceous extinction.
Food web recovery from mass extinction is poorly understood. We analyzed insect-feeding damage on 14,999 angiosperm leaves from 14 latest Cretaceous, Paleocene, and early Eocene sites in the western interior United States. Most Paleocene floras have low richness of plants and of insect damage. However, a low-diversity 64.4-million-year-old flora from southeastern Montana shows extremely high in...
متن کاملThe Cretaceous-Tertiary extinction: Modeling carbon flux and ecological response
[1] It is widely recognized that a significant negative excursion in carbon isotopic (dC) differences between planktic and benthic foraminiferal tests occurred at the Cretaceous-Tertiary (K-T) boundary. We applied parametric and nonparametric breakpoint tests and statistical comparisons of different recovery models to assess the timing and pattern of recovery from this negative excursion at Sou...
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ژورنال
عنوان ژورنال: Genetics Selection Evolution
سال: 1987
ISSN: 1297-9686
DOI: 10.1186/1297-9686-19-4-487