Debate Heats Up On Role Of Climate In Human Evolution

Eurekalert ^ | 11-3-2003 | Geological Society Of America

[blam]

Contact: Ann Cairns
acairns@geosociety.org
303-357-1056
Geological Society of America

Debate heats up on role of climate in human evolution

Boulder, Colo.- Scientists at the Geological Society of America annual meeting in Seattle next week are taking a comprehensive new look at drivers of human evolution. It now appears that climate variability during the Plio-Pleistocene (approximately 6 million years in duration) played a hugely important role. Astronomically controlled climate forcing on scales ranging from 20,000 to 100,000 years down to El Niños (5-7 years) made a highly unpredictable environment in which generalists with intelligence, language, and creativity were best able to adapt. Traditional studies of human evolution have focused largely on finding and dating hominid fossils. Today the investigation is rapidly expanding with advances in DNA research and understanding of global climate change. The combination of archeological, geologic, and paleoclimatic evidence allows scientists to explore such tantalizing questions as:

What were the drivers that may have nudged hominids toward bi-pedalism? Why did only one species ultimately succeed at it? How might global climate change have influenced brain development, development of tools, and the exodus from Africa? How did glacial periods in Europe, Asia, and North America impact humans? "The answers to these questions will not all come from the bones, but from what was taking place in the environment in which they were found," says Gail Ashley, Dept. of Geological Sciences, Rutgers University.

Ashley and Craig Feibel of Rutgers have assembled an interdisciplinary group of distinguished scientists – physical anthropologists, archaeologists, geologists, and paleoclimatologists – for a Pardee Keynote Symposia, The Paleoenvironmental and Paleoclimatic Framework of Human Evolution. The symposium takes place at GSA on Monday, Nov. 3.

William Ruddiman, celebrated author of Earth's Climate: Past and Future, provides an overview of climate change over the last several million years, helping to separate fact from fiction.

Bernard Wood, a world-renowned physical anthropologist, discusses the hominin family "Tree of Life" and the challenges of working with the meager fossil record of human evolution spanning the last 7 million years.

Thure Cerling is a pioneer in using isotope records of bones and teeth. With co-authors Meave Leakey and John Harris he provides a comprehensive look at the impact of climate change on the biological record from one of richest fossil sites in the world (Lake Tukana, Kenya).

Jonathan Wynn unravels some of the paleoclimate puzzles from fossil soils at key sites in the "Cradle of Mankind" in East Africa. The soils provide clear documentation of extremely arid events. Prolonged droughts may have been a factor in triggering migrations of hominins out of Africa.

Julia Lee-Thorpe, a trail blazing geochemist, has taken a more personal approach to human evolution by examining hominin nutrition through analyses of tooth enamel. Diet is a direct record of available food resources and an indirect record of the environment in which the individual lived.

Andrew Hill, a globally recognized expert on the paleontological record in East Africa, reports on the latest findings from the superb paleoenvironmental record of the Tugen Hills, Kenya (site of the discovery of the 6 million-year-old "Millennium Man").

Gail Ashley speculates on the critical role of the availability of water in affecting human evolution, based on studies from Olduvai Gorge and other fossil localities. Dramatic fluctuations in climate (wet to dry) in East Africa may have been an important factor in affecting natural selection of species able to cope through arid periods.

David Lordkipanidze and Reid Ferring tell an exciting chapter on the "Out-of-Africa" story from Dmanisi, Republic of Georgia. The 1.8 million-year-old hominin remains are the first discoveries outside Africa to show clear affinities to early African Homo.

Rick Potts, author of the provocative book Humanity's Descent: The Consequences of Ecological Instability, contributes important new findings from China revealing the successful adaption of some hominin groups 400,000 years ago to climatic fluctuations and drastic environmental change.

James Dixon, a recognized authority on peopling of the Americas, provides the most recent chapter in the record of humans. Continental ice sheets, sea level changes and the presence of the Bering land bridge effectively controlled immigration from Asia to the New World.

Craig Feibel provides perspective on the physical environmental constraints in which human evolution took place. He examines the role of geologic factors such as plate tectonics, sea level change, and climate fluctuations in affecting selective pressure on hominins and thereby impacting how and where humans evolved. The Paleoenvironmental and Paleoclimatic Framework of Human Evolution Monday, Nov. 3, 8:00 a.m.-12:00 p.m., WSCTC Ballroom 6B

During the GSA Annual Meeting, Nov. 2-5, contact Ann Cairns at the GSA Newsroom, Washington State Convention Center and Trade Center, Seattle, for assistance and to arrange for interviews: 206-219-4615.

Geological Society of America 115th Annual Meeting Nov. 2-5, 2003 Washington State Convention and Trade Center Seattle, WA, USA

Geological Society of America www.geosociety.org

[Consort]

Hot weather and tight pants produce inferior sperm.

[RadioAstronomer]

Ping! Possibly for your ping list?

[U S Army EOD]

If you currently don't have the technoligy to live with it, you beat feet. This would explain why Northern Africa got a head start on Northern Europe. Also, Northern Europe may have been more advanced than we think. When you build things out of wood they just don't last as long as things built out of limestone. Then there is no record to show you were there.

[DuncanWaring]

I ran into a claim about five years ago in "Discover" magazine that the human race could be attributed to ... Panama.

The theory was that a long time ago, there was no Isthmus of Panama, and some ocean current flowed through the gap between North and South America from the Atlantic to the Pacific Ocean.

When the Isthmus of Panama rose from the sea, this current was deflected back into the Atlantic, toward Africa. As a result, Africa became cooler and more humid, somehow favoring the rise of homo sapiens.

[blam]

"The theory was that a long time ago, there was no Isthmus of Panama, and some ocean current flowed through the gap between North and South America from the Atlantic to the Pacific Ocean."

I think that was in the millions of years ago...not positive though. (I would like to know if you find out for sure...I could work with that, lol)

[Ichneumon]

No scientist would ever use such an ignorant term as "human evolution."

That's going to come as a big surprise to the scientists who publish and submit articles to scientific journals such as:

...or those scientists who publish such papers as:

Tracing the LINEs of human evolution (Igor Ovchinnikov, Adrienne Rubin, and Gary D. Swergold) [Excellent paper]

A Review of Sexual Selection and Human Evolution: How Mate Choice shaped Human Nature

Alu Insertion Polymorphisms and Human Evolution: Evidence for a Larger Population Size in Africa (Mark Stoneking, Jennifer J. Fontius, Stephanie L. Clifford, Himla Soodyall, Santosh S. Arcot, Nilmani Saha, Trefor Jenkins, Mohammad A. Tahir, Prescott L. Deininger, and Mark A. Batzer)

Human evolution: Sex-specific contributions to genome variation (Todd R. Disotell)

Population Bottlenecks and Pleistocene Human Evolution (John Hawks, Keith Hunley, Sang-Hee Lee, and Milford Wolpoff)

Transitions in human evolution and faunal changes during the Pleistocene in Latium (Central Italy) (G. Manzi1, M.R. Palombo, L. Caloi, F. Mallegni)

And so on and so on.

Evolution is not science,

Of course it is, but you're welcome to try to offer an argument why you think it isn't, if you actually have one.

it is the ignorant religion of the God haters.

That's going to come as a big surprise to the millions of Christians who accept evolution.

Objective science proves that creation is undeniable fact.

Ooh, this ought to be interesting -- why don't you provide us some specific examples of the "objective science" which "proves" that creation is an "undeniable fact"?

[LiteKeeper]

YEC INTREP

[U S Army EOD]

I sure wish I had read the book on how mate choices shaped human nature before I met my second ex wife.

[rightofrush]

What were the drivers that may have nudged hominids toward bi-pedalism?

See any book by Elaine Goodman, The Aquatic Ape, Descent from Woman, etc.

[E.G.C.]

BTTT!!!!!

[Junior]

Except civilizations arose initially in two relatively benign areas along the banks of major rivers...

[PatrickHenry]

PING. [This ping list is for the evolution side of evolution threads, and sometimes for other science topics. FReepmail me to be added or dropped.]

[js1138]

Civilization requires grain storage, or some equivalent.

[stanz]

You have to note also that the more advanced cultures seem to be where there was the most change. They had to be smart to survive.

Conversely, in extant primitive societies there hasn't been the environmental pressure over time to enforce change. Their technology required few tweakings and cultural practices remained essentially static.

[Alamo-Girl]

Thanks for the heads up!

[Physicist]

What were the drivers that may have nudged hominids toward bi-pedalism?

It seems to me that we've discussed this before.

[U S Army EOD]

Which is why some cultures get left behind.

[stanz]

Their misfortune for having been assimilated into Western encroachment.

[blam]

The Cold Snap That Civilized The World

[U S Army EOD]

This is probably true. But, would it be any more moral if they did it to us first? If you aren't willing to utilize the land you are on to the benefit of mankind in general, should you be allowed to keep it? Should we give the Stonehendge area back to the Picts?