Navigation Links
Newfound ancient African megadroughts may have driven the evolution of humans and fishes
Date:10/8/2007

From 135,000 to 90,000 years ago tropical Africa had megadroughts more extreme and widespread than any previously known for that region, according to new research.

Learning that now-lush tropical Africa was an arid scrubland during the early Late Pleistocene provides new insights into humans' migration out of Africa and the evolution of fishes in Africa's Great Lakes.

"Lake Malawi, one of the deepest lakes in the world, acts as a rain gauge," said lead scientist Andrew S. Cohen of The University of Arizona in Tucson. "The lake level dropped at least 600 meters (1,968 feet) -- an extraordinary amount of water lost from the lake. This tells us that it was much drier at that time."

He added, "Archaeological evidence shows relatively few signs of human occupation in tropical Africa during the megadrought period."

The new finding provides an ecological explanation for the Out-of-Africa hypothesis that suggests all humans descended from just a few people living in Africa sometime between 150,000 and 70,000 years ago.

"We've got an explanation for why that might have occurred -- tropical Africa was extraordinarily dry about 100,000 years ago," said Cohen, a UA professor of geosciences. "Maybe human populations just crashed."

Other researchers have documented droughts in individual regions of Africa at that time, such as the Kalahari desert expanding north and the Sahel expanding south, he said. "But no one had put it together that those droughts were part of a bigger picture."

Tropical Africa's climate became wetter by 70,000 years ago, a time for which there is evidence of more people in the region and of people moving north. As the population rebounded, people left Africa, Cohen said.

The newly discovered drastic drought also suggests the famous cichlid fishes of Lake Malawi evolved four to eight times slower than previously thought, altering scientists' view of fish evolutio
'/>"/>

Contact: Mari N. Jensen
mnjensen@email.arizona.edu
520-626-9635
University of Arizona
Source:Eurekalert

Page: 1 2 3 4

Related biology news :

1. Newfound roadblock to interferon effectiveness against malignant melanoma
2. Ancient olfaction protein is shared by many bugs, offering new pest control target
3. Researchers find missing genes of ancient organism
4. Family trees of ancient bacteria reveal evolutionary moves
5. Scientists find fossil proof of Egypts ancient climate
6. U-M team recovers ancient whale in Egyptian desert
7. Ancient immune defense mechanism is no match for HIV-1
8. Ancient DNA helps clarify the origins of two extinct New World horse species
9. Deep sea algae connect ancient climate, carbon dioxide and vegetation
10. Analysis of flower genes reveals the fate of an ancient gene duplication
11. Researchers Discover Ancient Origins Of Tuberculosis-causing Bacteria
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/9/2015)... , Feb. 9, 2015  Lintec of America ... methods for carbon nanotube (CNT) macrostructures, including sheets, yarns ... Dallas (UTD). Leveraging the vast industrial resources ... Tokyo, Japan , Lintec of America is forming ... Richardson, TX , focusing on scaling up the ...
(Date:2/5/2015)... , Jan. 26, 2015 NXT-ID, Inc. (NASDAQ: ... a biometric authentication company focused on the growing mobile ... website ( http://www.nxt-id.com/ ) as part of its 2015 ... The Company launched its new consumer website for Wocketwallet.com ... , CEO of NXT-ID said, "Our new corporate website ...
(Date:2/5/2015)... , Jan. 28, 2015 Research and Markets ... addition of the "Global Biometrics Market (2014-2020): ... and Countries " report to their offering. ... Asia-Pacific is anticipated to overtake ... owing to increasing government spending towards IT security, ...
Breaking Biology News(10 mins):Lintec announces exclusive license to commercialize innovative carbon nanotube technology from the University of Texas at Dallas 2Lintec announces exclusive license to commercialize innovative carbon nanotube technology from the University of Texas at Dallas 3Lintec announces exclusive license to commercialize innovative carbon nanotube technology from the University of Texas at Dallas 4NXT-ID, Inc. Launches New Corporate Website As Part Of Ongoing 2015 Branding Initiatives For Wocket Smart Wallet 2NXT-ID, Inc. Launches New Corporate Website As Part Of Ongoing 2015 Branding Initiatives For Wocket Smart Wallet 3Global Biometrics Market (2014-2020): Market Forecast By Technologies, Applications, End Use, Regions and Countries 2Global Biometrics Market (2014-2020): Market Forecast By Technologies, Applications, End Use, Regions and Countries 3
... diet, exercise and reduced stress not only can lead to ... new study by a team of researchers, including one from ... The study shows that swallows who maintained a ... were those who produced the most young. The ...
... viruses as they evolved over hundreds of generations to infect ... defences, the viruses evolved at a quicker rate and generated ... to adapt to the viral infection. The study shows, ... Van Valen was correct in his ,Red Queen Hypothesis,. ...
... scientists from the NOAA-funded Gulf of Maine Toxicity (GOMTOX) project ... toxic alga that can cause ,red tides, in the spring ... shellfish industry. An abundant seed population in bottom ... the toxic alga Alexandrium fundyense. This organism swims in ...
Cached Biology News:Study points to role of antioxidant balance in bird health and reproduction 2Study points to role of antioxidant balance in bird health and reproduction 3Scientists reveal driving force behind evolution 2Researchers issue outlook for a significant New England 'red tide' in 2010 2Researchers issue outlook for a significant New England 'red tide' in 2010 3
(Date:2/27/2015)... and Markets ( http://www.researchandmarkets.com/research/p2ddnr/global_market ) has announced the ... report to their offering. , Global Market ... on Trypsin globally and regionally ( Europe , ... , Latin America etc.). It captures ... This report focuses on three primary areas; manufacture methods & ...
(Date:2/27/2015)... , Feb. 27, 2015  Pfenex Inc. (NYSE MKT: ... of biosimilar therapeutics, today announced that it will be ... Marquis on March 2 nd at 3pm PST. Patrick ... a panel discussing the current state of the biosimilar ... . For more information on CALBIO ...
(Date:2/27/2015)... 2015   PureTech , a science and technology ... products and technologies in the healthcare sector, announced today ... and Member of the Board of Directors of Sanofi, ... has been a pleasure to know Chris for many ... be working together more closely now," said Dr. ...
(Date:2/26/2015)... - SQI Diagnostics Inc. ("SQI" or the "Company") (TSX-V: ... and commercializes proprietary technologies and products for advanced microarray ... the fiscal first quarter ended December  31, 2014. All ... (CAD), unless otherwise stated. "During the ... our existing customers and add to our sales pipeline," ...
Breaking Biology Technology:Global Market Report of Trypsin 2014-2018 2Christopher Viehbacher, former CEO of Sanofi, Joins PureTech's Board of Directors 2Christopher Viehbacher, former CEO of Sanofi, Joins PureTech's Board of Directors 3Christopher Viehbacher, former CEO of Sanofi, Joins PureTech's Board of Directors 4SQI Diagnostics Reports First Quarter Financial Results 2SQI Diagnostics Reports First Quarter Financial Results 3SQI Diagnostics Reports First Quarter Financial Results 4SQI Diagnostics Reports First Quarter Financial Results 5SQI Diagnostics Reports First Quarter Financial Results 6
... A public-private effort is moving toward making downtown Madison ... been chosen to enter negotiations for the right to ... The "Wireless Wisconsin" service would create a publicly accessible ... County Regional Airport. The project also has provisions for ...
... a provider of education products in Wisconsin Rapids, has ... John Stearns. , ,Generation21 lost $4.6 million before taxes ... said it had looked for strategic alternatives over the ... was its best option. , ,The company will record ...
... Schiefelbein has a warning for chief information officers: By 2007, ... lower-level business executives. The CEO of Paragon Development Systems ... to work to stay involved with the business side of ... a big change in a really short period of time," ...
Cached Biology Technology:Madison wi-fi plans move ahead 2IT outsourcing remains on the horizon as companies focus on core business 2IT outsourcing remains on the horizon as companies focus on core business 3
The SVT3-2 diverter valve is a 3-port, 2-position valve for use with the BioLogic DuoFlow system....
4',6-Diamidino-2-phenylindole, dihydrochloride (DAPI)...
... PROTEAN II xi multi-cell is for 2-D separations. ... cooling capabilities. The PROTEAN II xi multi-cell can ... type of glass plates, and cooling system. The ... to the PROTEAN II XL multi-cell for a ...
... developed with the drug discovery process in ... and performance, Safire is the ideal instrument ... and high throughput screening. Safire is a ... offers a range of high speed detection ...
Biology Products: