Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Early human habitat was savanna, not forest

28.05.2010
Pre-humans living in East Africa 4.4 million years ago inhabited savannas -- grassy plains dotted with trees and shrubs -- according to a team of researchers that includes earth science Naomi Levin of The Johns Hopkins University's Krieger School of Arts and Sciences.

This conclusion is at odds with a theory – which holds that these early beings lived in a mostly forested environment – put forth by prominent University of California at Berkeley researcher Tim D. White and his team in a 2009 issue of the journal Science.

"Our team examined the data published by White and his colleagues last October and found that their data does not support their conclusion that Ardipithecus ramidus lived exclusively in woodlands and forest patches," said Levin, whose team published a commentary on the matter in today's issue of Science. "The White team's papers stress the wooded nature of A. ramidus's environment and say specifically that Ardi did not live in a savanna. Yet, the actual data they present are consistent with exactly that: a savanna environment with a mix of grasses and trees."

This criticism is important because the claim that the 4.4 million-year-old fossil nicknamed "Ardi" lived in woodlands and forest patches was used as an argument against a longstanding theory of human evolution known as the "savanna hypothesis." According to that premise, the expansion of savannas – grassy plains dotted with trees and shrubs – prompted our ape-like forebears to descend from trees and begin walking upright to find food more efficiently, or to reach other trees for resources or shelter.

Levin, an assistant professor of earth and planetary sciences at Johns Hopkins, was part of a team of eight geologists and anthropologists from seven universities led by Thure E. Cerling of the University of Utah. They used the White team's own data to draw very different conclusion about the environment inhabited by Ardi, an omnivorous, ape-like creature that stood about 4 feet tall and had a brain less than a quarter of the size of a modern day human's. This data was collected from ancient soils, plant fossils and other remains in the area now known as Aramis, in Ethiopia.

Levin's team found that tropical grasses, in fact, comprised between 40 and 60 percent of the biomass in Ardi's world.

Levin says her team's conclusion is noteworthy because, if scientists are to evaluate the environmental pressures that triggered the evolutionary success of some traits over others, they must clearly understand the environment itself.

"In their papers and summaries, White and his colleagues emphasize that A. ramidus had a mix of traits that suggest it was at ease both walking upright on the ground and moving through the trees on its palms," Levin explains. "If the habitat of A. ramidus was, in fact, a woodland with forest patches, where grasses were rare, then it's unlikely that the increased presence of grassy environments were the driving force behind the origin of upright walking in early human ancestors. However, if the habitat of A. ramidus included savannas where grasses were up to 60 percent of the available biomass, then we cannot rule out the possibility that open environments played an important role in human origins and, in particular, in the origins of upright walking. The scientific community and the public should not accept an exclusively woodland/forested habitat for A. ramidus and the origins of upright walking, because the data do not support it."

The critique concludes that although its authors do not judge the validity of the savanna hypothesis, the connection between human ancestors walking upright and the expansion of grasslands remains a viable idea.

Contact the Office of News and Information at Lde@jhu.edu or 443-287-9960 for a copy of the Science article.

Related links: Levin's webpage: http://eps.jhu.edu/bios/naomi-levin/index.html

Lisa DeNike | EurekAlert!
Further information:
http://www.jhu.edu

Further reports about: Science TV planetary science tropical grass upright walking

More articles from Earth Sciences:

nachricht World’s oldest known oxygen oasis discovered
18.01.2018 | Eberhard Karls Universität Tübingen

nachricht A close-up look at an uncommon underwater eruption
11.01.2018 | Woods Hole Oceanographic Institution

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>