Earth Science News  





. How Our Ancestors Were Like Gorillas

The research used 35 fossilised specimens of Paranthropus robustus, an extinct relative of Homo sapiens which existed almost two million years ago. The fossils came from the palaeontological sites of Swartkrans, Drimolen and Kromdraii, all of which are in South Africa's Cradle of Humankind World Heritage Site near Johannesburg.
by Staff Writers
London, UK (SPX) Nov 30, 2007
Research published in this week's Science journal shows that some of our closest extinct relatives had more in common with gorillas than previously thought. Dr Charles Lockwood, UCL Department of Anthropology and lead author of the study, said: "When we examined fossils from 1.5 to 2 million years ago we found that in one of our close relatives the males continued to grow well into adulthood, just as they do in gorillas.

This resulted in a much bigger size difference between males and females than we see today.

"It's common knowledge that boys mature later than girls, but in humans the difference is actually much less marked than in some other primates. Male gorillas continue to grow long after their wisdom teeth have come through, and they don't reach what is referred to as dominant "silverback" status until many years after the females have already started to have offspring.

"Our research makes us think that, in this fossil species, one older male was probably dominant in a troop of females. This situation was risky for the males and they suffered high rates of predation as a result of both their social structure and pattern of growth."

The research used 35 fossilised specimens of Paranthropus robustus, an extinct relative of Homo sapiens which existed almost two million years ago. The fossils came from the palaeontological sites of Swartkrans, Drimolen and Kromdraii, all of which are in South Africa's Cradle of Humankind World Heritage Site near Johannesburg.

The research was inspired by earlier discoveries at Drimolen by Dr Andre Keyser, one of the co-authors of the study. Dr Colin Menter, from the University of Johannesburg and co-director of current fieldwork at Drimolen, explains: "Discoveries at this site showed us that sex differences in Paranthropus robustus were greater than we had previously thought. While there are some specimens from Drimolen that are just as large and robust as those from other sites like Swartkrans, there is a complete female skull that is distinctly smaller than the other, well-preserved specimens of the species."

Jacopo Moggi-Cecchi, based at the University of Florence and an expert on fossil teeth, participated in the study and says: "It takes large samples of fossils to ask questions about variation and growth, and it's really a tribute to fieldworkers such as Robert Broom and Bob Brain [who worked at Swartkrans] that this research could even take place. It's also an example of why we need to continue to look for fossils after we think we know what a species is - more specimens allow us to answer more interesting questions. Even isolated teeth can give us new insights into what variation means."

Dr Lockwood adds: "The pattern of growth also gives a better understanding of who is male and who is female in this sample of skulls and it turns out that there are far more males in the fossil sample. Because fossils from the most prolific site, Swartkrans, are thought to have been deposited by predators such as leopards and hyenas, it appears that males were getting killed more often than females.

"Basically, males had a high-risk, high-return lifestyle in this species. They most likely left their birth groups at about the time they reached maturity, and it was a long time before they were mature enough to attract females and establish a new group. Some of them were killed by predators before they got the chance."

A final point made by the researchers is that not all fossil hominin samples show the same patterns, and it is quite possible that further work will reveal clear diversity in social structure between human ancestors, in the same way that one sees differences among apes such as chimpanzees, bonobos, gorillas, and orangutans. This research will help us to understand how human social structure evolved.

Community
Email This Article
Comment On This Article

Related Links
University College London
All About Human Beings and How We Got To Be Here




Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
Study Supports Single Main Migration Across Bering Strait
Ann Arbor MI (SPX) Nov 29, 2007
Did a relatively small number of people from Siberia who trekked across a Bering Strait land bridge some 12,000 years ago give rise to the native peoples of North and South America? Or did the ancestors of today's native peoples come from other parts of Asia or Polynesia, arriving multiple times at several places on the two continents, by sea as well as by land, in successive migrations that began as early as 30,000 years ago?

.
Get Our Free Newsletters Via Email
  



  • More deaths as storms exit the Philippines
  • NORTHCOM Experience Lends Lessons To Bangladesh Relief
  • US marines assist stepped up relief effort in Bangladesh
  • LSU Helps Bangladesh Save Lives By Providing Storm Surge Models 24 Hours In Advance Of Cyclone Sidr

  • Having The Climate Cake And Eating It Too
  • New Research Discredits 100 Billion Dollar Global Warming Fix
  • In Bali The Other USA Will Be With The World
  • Australia risks breaching Kyoto: expert

  • Ministerial Summit On Global Earth Observation System Of Systems
  • China, Brazil give Africa free satellite land images
  • NASA-Conceived Map Of Antarctica Lays Ground For New Discoveries
  • Rosetta: Earth's True Colours

  • ORNL Super Water Repellent Could Cause Big Wave In Market
  • Scientists convert cellulose into hydrogen
  • Helium Isotopes Point To New Sources Of Geothermal Energy
  • Small UAV Again Achieves Record Flight Time Using Protonex Fuel Cell System Technology

  • China says estimated HIV/AIDS cases rise to 700,000
  • UN cuts AIDS infection estimate: report
  • Repellents Between Dusk And Bedtime Make Insecticide-Treated Bednets More Effective
  • Global Fund approves over 1 bln dlrs in new grants to fight disease

  • Wildlife Conservation Society Study Finds Seasonal Seas Save Corals With Tough Love
  • A Prehistoric Forest Emerges From A Farmer's Pond
  • Group Selection, A Theory Whose Time Has Come...Again
  • Living Time Capsules

  • China reports progress on cutting pollution, but not enough
  • Atmospheric Measuring Device For Understanding Smog Formation
  • China pollution costs 5.8 pct of GDP: report
  • Local Sources Major Cause Of US Near-Ground Aerosol Pollution

  • How Our Ancestors Were Like Gorillas
  • Study Supports Single Main Migration Across Bering Strait
  • Environmental Researchers Propose Radical Human-Centric Map Of The World
  • Environmental Exodus

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2007 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement