Results 281 to 290 of about 3,255,505 (313)

Delayed biological recovery from extinctions throughout the fossil record

Nature, 2000
How quickly does biodiversity rebound after extinctions? Palaeobiologists have examined the temporal, taxonomic and geographic patterns of recovery following individual mass extinctions in detail, but have not analysed recoveries from extinctions throughout the fossil record as a whole.
J W, Kirchner, A, Weil
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Global extinctions and the biological evolution

Journal of Palaeosciences, 1995
The biosphere evolution is shown to accompany geodynamic processes and follow different-order cycles of the galactic motion of the Solar System. Restricted to critical points of the cycles are global epochs of nascencies and extinctions of taxa whose rank corresponds to a scale of geodynamic activation at their origin in critical points of the Earth’s ...
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Extinction and backscatter cross sections of biological materials

SPIE Proceedings, 2007
Aerosol backscatter and extinction cross-sections are required to model and evaluate the performance of both active and passive detection systems. A method has been developed by which begins with laboratory measurements of thin films and suspensions of biological material to obtain the complex index refraction of the film from the UV to the LWIR ...
M. E. Thomas, M. B. Airola, C. C. Carter, N. T. Boggs   +3 more
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Biological selectivity of extinction

2005
Selective survival across major extinction event horizons is both a bothersome puzzle and an opportunity to delimit the biologically interesting question of causality. Heritable differences in characters may have predictable consequences in terms of differential species survival.
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Fitness Optimization and Decay of Extinction Rate Through Biological Evolution

Physical Review Letters, 1995
We present a simple theoretical model of evolution featuring a decreasing extinction rate due to an increasing average fitness of the species. The dynamics is based on a random walk on a rugged fitness landscape, with evolutionary jumps for each species triggered by the achievement of fitness records during the walk.
, Sibani, , Schmidt, , Alstrom
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Mass origination versus mass extinction: the biological contribution to the Pliensbachian–Toarcian extinction event

Journal of the Geological Society, 2000
The Pliensbachian–Toarcian bivalve mass extinction in the Andean Basin of South America is characterized by a sharp drop in species diversity, caused mainly by extinction of endemics, and an extended lag phase. Whilst analysis of community attributes such as guild diversity, number of associations, and species richness of samples constituting ...
M. ABERHAN, F. T. FÜRSICH
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Biological Extinction in Terms of Overadaptation

1991
Extinction has been a common phenomenon of the biosphere during the Earth’s past but it is also an enigmatic process in biological evolution. Various and numerous theories have been put forward to explain biological extinction, especially to explain mass extinction which marks the biostratigraphical boundaries in geohistory. Most of these explanations,
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Extinction in Systems of Interacting Biological Populations

1999
In Sect. 4.3 we already dealt with a single population that has a stochastic logistic dynamics. In this chapter we fully analyse two examples of two-dimensional systems: a prey-predator system and the epidemiological problem of contact between infectives and susceptibles. The method we use is rather complex.
Johan Grasman, Onno A. van Herwaarden
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Is the Tasmanian tiger extinct? A biological–economic re-evaluation

Ecological Economics, 2003
Abstract In the 1890s, a bounty scheme was implemented to rid Tasmania of the thylacine or Tasmanian tiger, a marsupial predator believed to wreak havoc on imported sheep flocks. The thylacine is now officially ‘possibly extinct’ and although, repeatedly, there have been alleged sightings in the wild, most people now believe the species is extinct as
Bulte, E.H., Horan, R.D., Shogren, J.F.
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Relationship between biological extinctions and geomagnetic reversals

Geology, 1980
It has been repeatedly suggested that reversals of Earth9s magnetic field play a controlling role in evolution. Empirical evidence put forward to support this hypothesis has come from comparisons of the stratigraphic positions of microfossil extinctions with individual reversals and from comparisons of various estimates of changes in Phanerozoic ...
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