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23 Jul 08

Diet and the evolution of the earliest human ancestors — PNAS

  • Numerous workers have recognized that microscopic wear on the incisors and
    molars of primates reflects tooth use and diet. For example, those primates that
    often use their front teeth in ingestion have high densities of microwear
    striations on their incisors. Furthermore, folivores have a high incidences of
    long narrow scratches on their molars, whereas frugivores have more pits on
    those surfaces. Among frugivores, hard-object feeders have even higher pit
    incidences than soft-fruit eaters. These and other relationships between
    microwear and feeding behaviors in living primates have been used to infer diet
    in fossil forms. Miocene apes have a remarkable range of microwear patterning,
    greatly exceeding that of living hominoids. For example, relatively high scratch
    densities suggest that Micropithecus, Rangwapithecus, and especially
    Oreopithecus (66) included more leaves in their diets. In
    contrast, high pit percentages suggest that Griphopithecus and
    Ouranopithecus (66) were hard-object specialists. Finally,
    intermediate microwear patterns suggest that most other species studied, such as
    Gigantopithecus, Dendropithecus, Proconsul,
    Dryopithecus    , and, perhaps, Sivapithecus (66–68), had diets dominated by soft fruits. These
    data give us a glimpse of the extraordinary variation from which the last common
    ancestor of apes and hominids evidently arose.
30 Jun 08

Evolution myths: Evolution produces perfect organisms - life - 19 April 2008 - New Scientist

Continual mutation also means that potentially useful features can get lost.
Many primates cannot make vitamin C, an ability that wasn't missed

www.newscientist.com/...roduces-perfect-organisms.html - Preview

evolution

  • Continual mutation also means that potentially useful features can get lost.
    Many primates cannot make vitamin C, an ability that wasn't missed in animals
    that get lots of vitamin C in their diet. However, such losses can be limiting
    if the environment changes, as one primate discovered on long sea voyages

Gut bugs may have guided the evolution of life - life - 22 May 2008 - New Scientist

  • The history of evolution could be written in an animal's excrement.

  • Trillions of mostly harmless bacteria and other microbes inhabit the guts of
    all mammals, outnumbering the number of mammalian cells by 10 to one.

  • 8 more annotations...

Handsome By Chance: Why Humans Look Different From Neanderthals

  • The scientists concluded that Neanderthals did not develop their protruding
    mid-faces as an adaptation to icy Pleistocene weather or the demands of using
    teeth as tools, and the retracted faces of modern humans are not an adaptation
    for language, as some anthropologists have proposed.


    Instead, random "genetic drift" is the likeliest reason for these skull
    differences

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