Science 1 June 2007:
Vol. 316. no. 5829, pp. 1328 - 1331
DOI: 10.1126/science.1140799
Reports
Origin of Human Bipedalism As an Adaptation for Locomotion on Flexible Branches
S. K. S. Thorpe,1* R. L. Holder,2 R. H. Crompton3*
Human bipedalism is commonly thought to have evolved from a quadrupedal terrestrial precursor, yet some recent paleontological evidence suggests that adaptations for bipedalism arose in an arboreal context. However, the adaptive benefit of arboreal bipedalism has been unknown. Here we show that it allows the most arboreal great ape, the orangutan, to access supports too flexible to be negotiated otherwise. Orangutans react to branch flexibility like humans running on springy tracks, by increasing knee and hip extension, whereas all other primatesdothe reverse. Human bipedalism is thus less an innovation than an exploitation of a locomotor behavior retained from the common great ape ancestor.
That's for you Dad! And somebody else's dad who once commented on my blog when I last heckled my dad about his interest in AAT! I'm sending the full text pdf of this paper to my dad - other dad, if you want it too, let me know where to send it.
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3 comments:
I don't know if you've ever seen my site which critiques the aquatic ape idea, but here's the link: Aquatic Ape Theory: Sink or Swim?
Hey thanks Jim - I've not only read it, I quote you in 'discussions' with my AAT-curious pals. Thanks for a great resource.
I've seen thousands of people swim and dive. I've never seen anyone walk on thin branches of trees like orangutans.
When they come down to the ground, orangs usually walk with their fists and feet quadrupedally, but when foraging in marshes they wade bipedally.
Some human divers can dive with no equipment 70m deep, but apes never submerge their faces fully in water.
Even in the middle of the Kalahari, folks always know where's the nearest water.
AAT is not about specialized aquatic mammals like whales, its about the waterside evolution of human ancestors, gathering foods (like calamari, oysters, fresh fish) in and around the seashores, like at Blombos cave, Klasies river, Langebaans, Pinnacle Point SA, Eritrean reefs, etc.
Sounds like your crew gets quite involved in water technology too.
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