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paleoanthropology, genetics and evolution

Neandertal

  • Meet Homo heidelbergensis

    Tue, 2011-11-15 08:28 -- John Hawks
    Synopsis: 
    The Mauer mandible is the type specimen of Homo heidelbergensis

    The Mauer mandible comes from just southeast of Heidelberg, Germany, and was found in ancient sands deposited just more than 600,000 years ago. Upon its description, the mandible was attributed to a new species, Homo heidelbergensis.

    Through the years, anthropologists considered H. heidelbergensis to be a more primitive species than Neandertals, very different from recent humans. Many anthropologists attribute other remains from the European Middle Pleistocene to this species. Probably the most important sample would be the Sima de los Huesos remains from Spain, but other crania and skeletal elements from sites across Europe have been put into the species. A few anthropologists would also include specimens from other parts of the world.

    Other anthropologists disagree. They believe that Mauer is an early member of the same population that includes Neandertals. Others would go further, noting the evidence that Neandertals are part of the ancestry of modern humans, and put Mauer into our species, Homo sapiens.

    This station has several mandibles for you to compare with Mauer, including some Neandertals, modern humans, and Homo erectus individuals.

    What to do: Compare the morphology of the Neandertal and Mauer mandibles to the modern humans. What features differ?

    Consider what you know about earlier hominid mandibles (or compare one at the station). Do you think Mauer is a possible ancestor of Neandertals? What about an ancestor of modern humans? Does it have mostly primitive dental features, or does it share derived features with one or the other?

  • Statures of fossil Homo

    Tue, 2011-09-13 00:25 -- John Hawks
    Synopsis: 
    A laboratory exercise that applies regression equations to estimate the statures of some fossil hominin femora.

    Homo erectus and Neandertals were more or less human-sized. That may not be saying much, since we are so variable in stature ourselves.

    In this case, the fossils don't entirely speak for themselves. To estimate the sizes of ancient people, working with long bones, we must apply some kind of regression or other estimation method.

    1. KNM-ER 1481 is a complete femur from Koobi Fora, Kenya, approximately 1.9 million years old. Without any associated skull or teeth, we can't be sure what species it represents. Many scientists attribute it to early Homo because of its differences from known australopithecine femora.
    2. The Trinil femur was found by Eugene Dubois in 1892 as he excavated fossil beds at Trinil, Java. He had found a human skullcap the year before, and after finding the femur's humanlike anatomy, Dubois named a new species, Pithecanthropus erectus. This is the original Homo erectus femur. Today, we are less certain about its age and association with the partial skull. It may be a million years old, but it may be substantially younger.
    3. The femur from Spy, Belgium, represents a Neandertal who lived around 45,000 years ago. This femur is part of a more complete skeleton, and exhibits many of the characteristic features of Neandertal long bones, including the great thickness and curvature of the shaft and very large joint surfaces.
    4. What to do: Here you will examine the fossil cast femora, using regression equations to predict stature of the individual.

      1. Determine the sex of the individual. The femur head diameter is a relatively good indicator of sex. If it is less than 44 mm, the individual is likely to be a female. More than 46 mm, and the individual is likely to be a male. In between these values, you may need more information — either from the rest of the skeleton or from the size and robusticity of the femur itself.
      2. Measure the maximum length of the femur. This measurement is taken using the osteometric board, and represents the maximum distance from any points on the proximal and distal ends of the bone. Take your measurement in centimeters.
      3. Apply the correct regression equation. These are specific to sex and race. The femora at this station come from donated anatomy collections from the early 20th century, and represent people of European ancestry. The male and female regression equations for this population are listed at right.
    Study questions: 
    1. What are some weaknesses of estimating body size for fossil humans by applying a regression drawn from a contemporary human population?
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Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

Acceleration

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.