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Map of early human migrations based on the Out of Africa theory; figures are in thousands of years ago (kya). [1]The peopling of the Americas began when Paleolithic hunter-gatherers (Paleo-Indians) entered North America from the North Asian Mammoth steppe via the Beringia land bridge, which had formed between northeastern Siberia and western Alaska due to the lowering of sea level during the ...
In Pennsylvania caves were used by newcomers as homes for a long time, certainly half a century. They generally were formed by digging into the ground about four feet in depth on the banks or low cliffs near the river front. The walls were then built up of sods or earth laid on poles or brush; thus half only of the chamber was really under ground.
Examples of Clovis and other Paleoindian point forms, markers of archaeological cultures in North America. The Solutrean hypothesis on the peopling of the Americas is the claim that the earliest human migration to the Americas began from Europe during the Solutrean Period, with Europeans traveling along pack ice in the Atlantic Ocean.
A troglobite (or, formally, troglobiont) is an animal species, or population of a species, strictly bound to underground habitats, such as caves.These are separate from species that mainly live in above-ground habitats but are also able to live underground (eutroglophiles), and species that are only cave visitors (subtroglophiles and trogloxenes). [1]
Other trogloxenic animals include vertebrates such as bears, hyenas, other predators, reptiles, oilbirds, cave swiftlets and even humans, that enter for short term shelter or for hibernation. Most of them contribute organic matter rather than consuming it, and are important resources for troglobitic insects, many of which actually specialise in ...
Humans also pose a threat to troglofauna. Mismanagement of contaminants (e.g. pesticides and sewage) may poison troglofaunal communities, [ 6 ] whilst removal of habitat, either directly or indirectly (e.g. rising watertable) is also a major threat.
Subterranean fauna is found worldwide and includes representatives of many animal groups, mostly arthropods and other invertebrates.However, there is a number of vertebrates (such as cavefishes and cave salamanders), although they are less common.
Schematic illustration of maternal (mtDNA) gene-flow in and out of Beringia, from 25,000 years ago to present. The genetic history of the Indigenous peoples of the Americas is divided into two distinct periods: the initial peopling of the Americas from about 20,000 to 14,000 years ago (20–14 kya), and European contact, after about 500 years ago.