Wednesday, September 28, 2011

Rapid Temperature Increases In Early Human Evolution



The periods of rapid temperature change at the same time, the emergence of the first distant relatives of humans and the emergence and spread of stone tools, according to new research from the University of Liverpool.

Dr Matthew Grove School of Archaeology, Classics and Egyptology reconstructed the likely responses of human ancestors of the climate in the last five million years by using genetic modeling. When the results were mapped against the timeline of human evolution, Dr. Grove was that important events have coincided with periods of high temperature variability recorded.

Dr. Grove said. "The survey confirmed that a large human adaptive radiation - a model where the number of coexisting species increases rapidly, before crashing back down to near its previous level - has coincided with a prolonged period of climatic fluctuations After the onset of climate variability around 2.7 million years a number of new species appear in the fossil record, with most of them disappear to 1.5 million years. The first stone tools appear around 2, 6 million years, and no doubt helped some of these species to respond to rapidly changing climatic conditions.

"1.5 million years ago, we are left with a man -. ancestor of erectus erectus The key to survival Gay Gay shows the flexibility of behavior - it is a kind of geographical coverage and the season lasts more than half a million years while other species may be specialized areas. has since been lost - due to their extinction -. erectus gay seems to have been universal, able to handle a variety of climatic and environmental costs "

The research of Dr. Grove is the first to explicitly "variability selection" model, an evolutionary process proposed by Professor Rick Potts in late 1990, and supports the pervasive influence of this process in human evolution. Selection of variability suggests that changes to the abrupt climate fluctuations, must comply with the variety of habitats, instead of every house, in turn, the time of selection variability created by Dr. Grove suggests that Homo erectus could be a product of exactly this process.

Linking climate fluctuations for the evolutionary process has implications for the current debate on global climate change. Dr. Grove, said: "Although it is often discussed under the banner of" global warming ", what we see in many parts of the world today is actually a greater range of annual temperatures and conditions, which means, in particular that the people of the third human world, many of them live in what is already marginal environments, they face increasingly difficult situations. The current model of climate change induced by man is like nothing we've seen before, and is disproportionate regions whose inhabitants have the technology to deal with it. "

The research is published in The Journal of Human Evolution and the Journal of Archaeological Science.

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