scholarly journals A biogeographic perspective on the evolution of fire syndromes in pine trees ( Pinus : Pinaceae)

2018 ◽  
Vol 5 (3) ◽  
pp. 172412 ◽  
Author(s):  
Kevin J. Badik ◽  
Joshua P. Jahner ◽  
Joseph S. Wilson
Keyword(s):  
North America ◽  
New World ◽  
Historical Biogeography ◽  
Ancestral State ◽  
Land Bridge ◽  
Mountain Ranges ◽  
Bering Land Bridge ◽  
Pine Trees ◽  
Dispersal Events ◽  
The Relationship

Our goals were to explore the relationship between biogeography and the evolution of fire-adaptive syndromes in the genus Pinus . We used a previously published time-calibrated phylogeny and conducted ancestral trait reconstruction to estimate the likely timing of diversification in Pinus , and to determine when fire-adaptive syndromes evolved in the lineage. To explore trait conservation among fire syndromes and to investigate historical biogeography, we constructed ancestral state reconstructions using the program RASP and estimated the degree of conservatism for fire-adapted traits in the program BaTS. Our reconstructions suggest that the Bering land bridge, which connected North America and Asia, probably played a major role in early pine evolution. Our estimates indicated that fire-adaptive syndromes seem to have evolved more frequently in New World taxa and probably are related to the uplift of major North American mountain ranges. Our data suggest that certain geographically widespread adaptations to fire evolved repeatedly, possibly due to localized changes in climate and environment, rather than resulting from large dispersal events of pre-adapted individuals.

Flake Tools in the American Arctic: Some Speculations

1964 ◽  
Vol 29 (3) ◽  
pp. 338-344 ◽  
Author(s):  
Edwin N. Wilmsen
Keyword(s):  
North America ◽  
Central Asia ◽  
New World ◽  
Yukon Territory ◽  
River Delta ◽  
The Arctic ◽  
Land Bridge ◽  
Bering Land Bridge

AbstractTwo sites, Kogruk (at the summit of Anaktuvuk Pass, Alaska) and Engigstciak (at the head of the Firth River delta, Yukon Territory, Canada), have recently yielded flake-tool assemblages which show striking resemblances to a Eurasiatic flake-blade tradition based on a Levallois-Mousterian stone-chipping technique, and to the Clovis flake-blade tradition of America which appears to be based on a similar chipping technique. It is suggested that these traditions are historically related and that the Arctic sites provide a possible link between the two. The presence of incipient fluting in Siberia and at Engigstciak may prove significant. Dating is discussed in terms of the ecology and geology of the sites and is correlated with the probable periods of availability of the Bering land bridge. An upland-foothills zone is seen to be essentially continuous from central Asia to central North America. It is suggested that this zone provided the only environmentally compatible link between the two continents, and that it was therefore the most probable route of early hunting peoples into the New World.

scholarly journals Setting the Stage: The Late Pleistocene Colonization of North America

Quaternary ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Michael O’Brien
Keyword(s):  
North America ◽  
Late Pleistocene ◽  
New World ◽  
Pacific Coast ◽  
Ice Sheets ◽  
Land Bridge ◽  
Projectile Points ◽  
Bering Land Bridge ◽  
The Pacific ◽  
Northern Half

The timing of human entrance into North America has been a topic of debate that dates back to the late 19th century. Central to the modern discussion is not whether late Pleistocene-age populations were present on the continent, but the timing of their arrival. Key to the debate is the age of tools—bone rods, large prismatic stone blades, and bifacially chipped and fluted stone weapon tips—often found associated with the remains of late Pleistocene fauna. For decades, it was assumed that this techno-complex—termed “Clovis”—was left by the first humans in North America, who, by 11,000–12,000 years ago, made their way eastward across the Bering Land Bridge, or Beringia, and then turned south through a corridor that ran between the Cordilleran and Laurentide ice sheets, which blanketed the northern half of the continent. That scenario has been challenged by more-recent archaeological and archaeogenetic data that suggest populations entered North America as much as 15,300–14,300 years ago and moved south along the Pacific Coast and/or through the ice-free corridor, which apparently was open several thousand years earlier than initially thought. Evidence indicates that Clovis might date as early as 13,400 years ago, which means that it was not the first technology in North America. Given the lack of fluted projectile points in the Old World, it appears certain that the Clovis techno-complex, or at least major components of it, emerged in the New World.

scholarly journals Assembly of the eastern North American herpetofauna: new evidence from lizards and frogs

2006 ◽  
Vol 2 (3) ◽  
pp. 388-392 ◽  
Author(s):  
J Robert Macey ◽  
James A Schulte ◽  
Jared L Strasburg ◽  
Jennifer A Brisson ◽  
Allan Larson ◽  
...  
Keyword(s):  
North America ◽  
North American ◽  
Eastern North America ◽  
Land Bridge ◽  
Dna Evidence ◽  
Bering Land Bridge ◽  
Biotic Diversity ◽  
Almost All ◽  
Dispersal Events ◽  
New Evidence

Darwin first recognized the importance of episodic intercontinental dispersal in the establishment of worldwide biotic diversity. Faunal exchange across the Bering Land Bridge is a major example of such dispersal. Here, we demonstrate with mitochondrial DNA evidence that three independent dispersal events from Asia to North America are the source for almost all lizard taxa found in continental eastern North America. Two other dispersal events across Beringia account for observed diversity among North American ranid frogs, one of the most species-rich groups of frogs in eastern North America. The contribution of faunal elements from Asia via dispersal across Beringia is a dominant theme in the historical assembly of the eastern North American herpetofauna.

scholarly journals Asymmetric biotic interchange across the Bering land bridge between Eurasia and North America

2019 ◽  
Vol 6 (4) ◽  
pp. 739-745 ◽  
Author(s):  
Dechun Jiang ◽  
Sebastian Klaus ◽  
Ya-Ping Zhang ◽  
David M Hillis ◽  
Jia-Tang Li
Keyword(s):  
North America ◽  
Opposite Direction ◽  
Environmental Changes ◽  
Strong Association ◽  
Disjunct Distribution ◽  
Dispersal Patterns ◽  
Land Bridge ◽  
Last Glacial Period ◽  
Bering Land Bridge ◽  
Dispersal Events

ABSTRACT The exchange of biotas between Eurasia and North America across the Bering land bridge had a major impact on ecosystems of both continents throughout the Cenozoic. This exchange has received particular attention regarding placental mammals dispersing into the Americas, including humans after the last glacial period, and also as an explanation for the disjunct distribution of related seed plants in eastern Asia and eastern North America. Here, we investigate bi-directional dispersal across the Bering land bridge from estimates of dispersal events based on time-calibrated phylogenies of a broad range of plant, fungus and animal taxa. We reveal a long-lasting phase of asymmetrical biotic interchange, with a peak of dispersal from Asia into North America during the late Oligocene warming (26–24 Ma), when dispersal in the opposite direction was greatly decreased. Influx from North America into Asia was lower than in the opposite direction throughout the Cenozoic, but with peak rates of dispersal at the end of the Eocene (40–34 Ma) and again in the early to middle Miocene (16–14 Ma). The strong association between dispersal patterns and environmental changes suggests that plants, fungi and animals have likely dispersed from stable to perturbed environments of North America and Eurasia throughout the Cenozoic.

THE IDENTIFICATION AND ORIGIN OF THE STRAINS OF THE LARCH SAWFLY, PRISTIPHORA ERICHSONII (HYMENOPTERA: TENTHREDINIDAE), IN NORTH AMERICA

1974 ◽  
Vol 106 (11) ◽  
pp. 1121-1131 ◽  
Author(s):  
Horne R. Wong
Keyword(s):  
North America ◽  
North American ◽  
Land Bridge ◽  
Bering Land Bridge ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly

AbstractThis study identifies and presents a key to five strains of the larch sawfly, Pristiphora erichsonii (Hartig), which are designated Aweme, Fernie, Ambleside, Thirlmire, and Salzburg.Aweme and Fernie strains occur only in North America and Salzburg strain is confined to Eurasia. Two Eurasian strains, Ambleside and Thirlmire, were accidentally introduced into Canada from England by 1913 among cocoons shipped for the release of the parasite Mesoleius tenthredinis Morley. It is postulated that the ancestors of Aweme-Salzburg strains Fernie–Thirlmire strains dispersed across the Bering Land Bridge into North America some time in the Miocene. These phyletic lines evolved into distinct Eurasian and North American strains. Early infestations in North America apparently consisted of North American strains, while later outbreaks have consisted primarily of the recently introduced Eurasian strains.

Evolutionary history of New World ticks of the genus Dermacentor (Ixodida: Ixodidae), and the origin of D. variabilis

2019 ◽  
Vol 127 (4) ◽  
pp. 863-875 ◽  
Author(s):  
Paula Lado ◽  
Hans Klompen
Keyword(s):  
North America ◽  
Evolutionary History ◽  
New World ◽  
Dermacentor Variabilis ◽  
Eastern North America ◽  
Western North America ◽  
Land Bridge ◽  
Phylogenetic Reconstructions ◽  
History Of ◽  
Migration Event

Abstract This study integrates biogeographical and phylogenetic data to determine the evolutionary history of the New World Dermacentor, and the origin of D. variabilis. The phylogenetic reconstructions presented here strongly support the hypothesis of an Afrotropical origin for Dermacentor, with later dispersal to Eurasia and the Nearctic. Phylogenetic and biogeographical data suggest that the genus reached the New World through the Beringia land bridge, from south-east Asia. The monophyly of the genus is supported, and most of the New World Dermacentor species appear as monophyletic. Dermacentor occidentals constitutes the sister lineage of D. variabilis, and the latter is subdivided into two well-supported clades: an eastern and a western clade. The western clade is genetically more variable than the eastern. The genus Dermacentor probably originated in Africa, and dispersed to the Palearctic and then to the New World through the Beringian route. Dermacentor variabilis appears to have originated in western North America, and then dispersed to eastern North America, probably in a single migration event.

scholarly journals Lions and brown bears colonized North America in multiple synchronous waves of dispersal across the Bering Land Bridge

2020 ◽  
Author(s):  
Alexander T Salis ◽  
Sarah C E Bray ◽  
Michael S Y Lee ◽  
Holly Heiniger ◽  
Ross Barnett ◽  
...  
Keyword(s):  
Population Dynamics ◽  
North America ◽  
Glacial Cycles ◽  
Land Bridge ◽  
Large Herbivores ◽  
Brown Bears ◽  
Sea Levels ◽  
North West ◽  
North East ◽  
Bering Land Bridge

AbstractThe Bering Land Bridge connecting North America and Eurasia was periodically exposed and inundated by oscillating sea levels during the Pleistocene glacial cycles. This land connection allowed the intermittent dispersal of animals, including humans, between Western Beringia (far north-east Asia) and Eastern Beringia (north-west North America), changing the faunal community composition of both continents. The Pleistocene glacial cycles also had profound impacts on temperature, precipitation, and vegetation, impacting faunal community structure and demography. While these paleoenvironmental impacts have been studied in many large herbivores from Beringia (e.g., bison, mammoths, horses), the Pleistocene population dynamics of the diverse guild of carnivorans present in the region are less well understood, due to their lower abundances. In this study, we analyze mitochondrial genome data from ancient brown bears (Ursus arctos; n = 103) and lions (Panthera spp.; n = 39), two megafaunal carnivorans that dispersed into North America during the Pleistocene. Our results reveal striking synchronicity in the population dynamics of Beringian lions and brown bears, with multiple waves of dispersal across the Bering Land Bridge coinciding with glacial periods of low sea levels, as well as synchronous local extinctions in Eastern Beringia during Marine Isotope Stage 3. The evolutionary histories of these two taxa underscore the crucial biogeographic role of the Bering Land Bridge in the distribution, turnover, and maintenance of megafaunal populations in North America.

A malaria parasite of the white-tailed deer ( Odocoileus virginianus ) and its relation with known species of Plasmodium in other ungulates

1980 ◽  
Vol 206 (1165) ◽  
pp. 395-402 ◽  
Keyword(s):  
Odocoileus Virginianus ◽  
New World ◽  
Mammalian Species ◽  
Common Source ◽  
Land Bridge ◽  
Old World ◽  
Bering Land Bridge ◽  
The Common ◽  
Old World Tropics ◽  
Plasmodial Infection

With the exception of the human malaria parasites, the mammalian species of Plasmodium have a fairly restricted geographical distribution, while the incidence of the infection in the different orders of mammals is patchy. A few species have been described in ungulates in the Old World Tropics, but Plasmodium odocoilei sp. nov. of the white-tailed deer ( Odocoileus virginianus ) of Texas is the first example to be found in the New World. It was discovered in an adult specimen that had had its spleen removed. Only the blood stages of the parasite are known, but these show various remarkable features: the presence of large vacuoles in the cytoplasm, and the enormous distortion and discoloration of the infected red blood cell. The phylogeny of the parasite is discussed in relation to that of the vertebrate host and it is suggested that Cervid stock crossed the Bering Land Bridge in the Pliocene Age, carrying a plasmodial infection that was the common source of malaria in the Old World Tragulidae and in the New World Odocoileus .

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