نتایج جستجو برای: pleistocene

تعداد نتایج: 8977  

2003
ANTONIA J. GOROG MARTUA H. SINAGA MARK D. ENGSTROM

The Sunda region of south-east Asia comprises the Malay Peninsula and the islands of Java, Sumatra and Borneo, all of which lie on a shallow continental shelf projecting from Indochina. Pleistocene glacial cycles caused sea levels to drop repeatedly, exposing vast areas of the Sunda shelf and creating land bridges among the islands and mainland. These land bridges, the latest of which connected...

Journal: :Proceedings. Biological sciences 1998
J C Avise D Walker

Pleistocene biogeographic events have traditionally been ascribed a major role in promoting speciations and in sculpting the present-day diversity and distributions of vertebrate taxa. However, this paradigm has recently come under challenge from a review of interspecific mtDNA genetic distances in birds: most sister-species separations dated to the Pliocene. Here we summarize the literature on...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Julie A Meachen Joshua X Samuels

Living coyotes modify their behavior in the presence of larger carnivores, such as wolves. However, little is known about the effects of competitor presence or absence on morphological change in coyotes or wolves over long periods of time. We examined the evolution of coyotes and wolves through time from the late Pleistocene, during which many large carnivorous species coexisted as predators an...

2017
G Veera Singham Ahmad Sofiman Othman Chow-Yang Lee

Dispersal of soil-dwelling organisms via the repeatedly exposed Sunda shelf through much of the Pleistocene in Southeast Asia has not been studied extensively, especially for invertebrates. Here we investigated the phylogeography of an endemic termite species, Macrotermes gilvus (Hagen), to elucidate the spatiotemporal dynamics of dispersal routes of terrestrial fauna in Pleistocene Southeast A...

Journal: :Current Biology 2007
Christopher Irwin Smith

Since Darwin first noted the impact of past ice ages on the distribution of organisms, biogeographers have debated whether Pleistocene glaciations shaped evolutionary patterns. A new synthesis of population genetics and palaeoclimatology promises unprecedented insights into Pleistocene evolutionary history.

Journal: :Molecular ecology 2009
Ross Barnett Beth Shapiro Ian Barnes Simon Y W Ho Joachim Burger Nobuyuki Yamaguchi Thomas F G Higham H Todd Wheeler Wilfried Rosendahl Andrei V Sher Marina Sotnikova Tatiana Kuznetsova Gennady F Baryshnikov Larry D Martin C Richard Harington James A Burns Alan Cooper

Lions were the most widespread carnivores in the late Pleistocene, ranging from southern Africa to the southern USA, but little is known about the evolutionary relationships among these Pleistocene populations or the dynamics that led to their extinction. Using ancient DNA techniques, we obtained mitochondrial sequences from 52 individuals sampled across the present and former range of lions. P...

2006
Peter Huybers

An agemodel not relying upon orbital assumptions is estimated over the last 2Ma using depth in marine sediment cores as a proxy for time. Agemodel uncertainty averages 10Ka in the early Pleistocene ( 2–1Ma) and 7Ka in the late Pleistocene ( 1Ma to the present). Twelve benthic and five planktic d O records are pinned to the agemodel and averaged together to provide a record of glacial variabilit...

2012
Larisa R. G. DeSantis Rachel A. Beavins Tracy Cassandra S. Koontz John C. Roseberry Matthew C. Velasco

Climate change alters species distributions, causing plants and animals to move north or to higher elevations with current warming. Bioclimatic models predict species distributions based on extant realized niches and assume niche conservation. Here, we evaluate if proxies for niches (i.e., range areas) are conserved at the family level through deep time, from the Eocene to the Pleistocene. We a...

2001
Brandon Dugan Peter B. Flemings Richard B. Alley Derek Elsworth Rudy L. Slingerland Barry Voight Peter Deines

Fluid pressures in Miocene-Pleistocene sediments of the US mid-Atlantic continental slope approach the lithostatic stress and are an important control on the stability of the slope. Fluid pressures in excess of hydrostatic were generated by regional depositional patterns and sedimentation rates. Fluid migration within porous and permeable Miocene silty sand layers redistributed pressure and gen...

Journal: :Journal of human evolution 2001
D D Stynder J Moggi-Cecchi L R Berger J E Parkington

The Hoedjiespunt 1 locality is an archaeological and palaeontological site located on the Hoedjiespunt Peninsula at Saldanha Bay, South Africa. In 1996 two human teeth, a left central mandibular incisor and a left lateral mandibular incisor, were discovered during excavations in the late Middle Pleistocene palaeontological layers. These teeth are described and are found to belong to a single su...

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