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Encyclopedia > Toba catastrophe theory

According to the Toba catastrophe theory, modern human evolution was affected by a recent, large volcanic event. The theory was proposed by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign.[1][2] Image File history File links Download high resolution version (1024x689, 149 KB) Picture of Mount Redoubt Eruption Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula. ... Image File history File links Download high resolution version (1024x689, 149 KB) Picture of Mount Redoubt Eruption Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula. ... Eruption column over Mount Pinatubo in the Philippines An eruption column consists of hot volcanic ash emitted during an explosive volcanic eruption. ... Mount Redoubt is an active volcano in the Aleutian Range on the Alaska Peninsula in Alaska, at 60°29 North 152°45 West. ... Human evolution is that part of biological evolution concerning the emergence of humans as a distinct species. ... Volcano 1. ... View of Lake Toba Lake Toba is a large lake, 100km long and 30km wide, in the middle of the northern part of the Indonesian island of Sumatra. ... The University of Illinois at Urbana-Champaign [[UIUC]], known as the U of I, is the flagship campus in the University of Illinois system. ...

Contents

History

Within the last three to five million years, after human and other ape lineages diverged from the hominid stem-line, the human line produced a variety of human species. Families Hylobatidae Hominidae Apes are the members of the Hominoidea superfamily of primates, which includes humans. ... Genera The hominids are the members of the biological family Hominidae (the great apes), which includes humans, chimpanzees, gorillas, and orangutans. ...


According to the Toba catastrophe theory, a massive volcanic eruption changed the course of human history by severely reducing the human population. This may have occurred when around 70–75,000 years ago the Toba caldera in Indonesia underwent a category 8 or "mega-colossal" eruption on the Volcanic Explosivity Index. This released energy equivalent to about one gigaton of TNT, three thousand times greater than that of Mount St. Helens. According to Ambrose, this reduced the average global temperature by 3 to 3.5 degrees Celsius for several years and may possibly have triggered an ice age. Human evolution is that part of biological evolution concerning the emergence of humans as a distinct species. ... View of Lake Toba Lake Toba is a large lake, 100km long and 30km wide, in the middle of the northern part of the Indonesian island of Sumatra. ... Satellite image of Santorini. ... VEI and ejecta volume correlation The Volcanic Explosivity Index (VEI) was devised by Chris Newhall of the U.S. Geological Survey and Steve Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions. ... A gigaton (or gigatonne) is a Metric Unit of mass, equal to 1,000,000,000 (1 billion) Metric tons, 1,000,000,000,000 (1 trillion) kilograms, or 1 quadrillion grams. ... Trinitrotoluene (TNT) is an explosive. ... The 1980 eruption of Mount St. ...


This massive environmental change is believed to have created population bottlenecks in the various species that existed at the time; this in turn accelerated differentiation of the isolated human populations, eventually leading to the extinction of all the other human species except for the branch that became modern humans. This article does not cite its references or sources. ... A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ...


Geological evidence

Some geological evidence and computed models support the plausibility of the Toba catastrophe theory, and genetic evidence suggests that all humans alive today, despite their apparent variety, are descended from a very small population, perhaps between 1,000 and 10,000 individuals.[citation needed] World geologic provinces Oceanic crust  0-20 Ma  20-65 Ma  >65 Ma Geologic provinces  Shield  Platform  Orogen  Basin  Large igneous province  Extended crust Geology (from Greek γη- (ge-, the earth) and λογος (logos, word, reason))[1] is the science and study of the solid matter of a celestial body, its composition...


Using the average rates of genetic mutation, some geneticists have estimated that this population lived at a time coinciding with the Toba event (see also Mitochondrial Eve and Y-chromosomal Adam). Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is the matrilineal most recent common ancestor for all living humans, from whom all mitochondrial DNA (mtDNA) in living humans is derived. ... In human genetics, Y-chromosomal Adam (Y-mrca) is the male counterpart to mitochondrial Eve: the most recent common ancestor from whom all male human Y chromosomes are descended. ...


Migration issues

According to this theory, humans once again fanned out from Africa after Toba when the climate and other factors permitted. They migrated first to Indochina and Australia, and later to the Fertile Crescent and the Middle East. A world map showing the continent of Africa. ... Indochina, or the Indochinese Peninsula, is a region in Southeast Asia. ... The Fertile Crescent is a historical region in the Middle East incorporating Ancient Egypt, the Levant, and Mesopotamia. ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ...


Migration routes to Asia created population centers in Uzbekistan, Afghanistan, and India.


Possibly substantial differences in skin color appeared as a result of varied melanin levels as local adaptations to varying ultraviolet intensities. Historical data for native populations collected by R. Biasutti prior to 1940. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks and browns or their mixed copolymers. ... The solar corona as seen in deep ultraviolet light at 17. ...


Europe became populated by migrants from the Caspian Sea region when the last ice age ended and Europe became more hospitable. The Caspian Sea is the largest lake on Earth by both area and volume,[1] with a surface area of 371,000 square kilometres (143,244 mi²) and a volume of 78,200 cubic kilometres (18,761 mi³).[2] It is a landlocked endorheic body of water and lies between... The Wisconsin (in North America), Weichsel (in Scandinavia), Devensian (in the British Isles), Midlandian (in Ireland) and Würm glaciation (in the Alps) are the most recent glaciations of the Pleistocene, which ended around 10,000 BC. The general glacial advance began about 70,000 BC, and reached its maximum... World map showing Europe A satellite composite image of Europe Europe is one of the seven traditional continents of the Earth. ...


See also

A supervolcano refers to a volcano that produces the largest and most voluminous kinds of eruption on Earth. ... A volcanic winter is the reduction in temperature caused by volcanic ash and droplets of sulfuric acid obscuring the sun, usually after a volcanic eruption (hence the name). ... A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ... Supervolcano is a two-part docudrama centered around the fictional eruption of the volcanic caldera of Yellowstone National Park. ... The examples and perspective in this article or section may not represent a worldwide view. ...

References

  1. ^ Stanley H. Ambrose (1998). "Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans". Journal of Human Evolution 34 (6): 623–651. DOI:10.1006/jhev.1998.0219.
  2. ^ Ambrose, Stanley H. (2005). Volcanic Winter, and Differentiation of Modern Humans. Bradshaw Foundation. Retrieved on 2006-04-08.

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... April 8 is the 98th day of the year in the Gregorian calendar (99th in leap years). ...

External links


  Results from FactBites:
 
Toba catastrophe theory - Wikipedia, the free encyclopedia (377 words)
The theory was proposed by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign.
According to the Toba catastrophe theory, a massive volcanic eruption changed the course of human history by severely reducing the human population.
Some geological evidence and computed models support the plausibility of the Toba catastrophe theory, and genetic evidence suggests that all humans alive today, despite their apparent variety, are descended from a very small population.
Lake Toba - Wikipedia, the free encyclopedia (339 words)
Lake Toba is a large lake, 100 km long and 30 km wide, in the middle of the northern part of the Indonesian island of Sumatra.
In 1949 the Dutch geologist Rein van Bemmelen reported that Lake Toba was surrounded by a layer of ignimbrite rocks, and was a large volcanic caldera.
Oceanographers discovered Toba ash on the floor of the eastern Indian Ocean and the Bay of Bengal.
  More results at FactBites »

 
 

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