monkey business

[Paul3eb]

you sure about that? i always thought one of the reasons other primates didn't evolve to our level (and the reason we did) was our opposable thumb that allows us to use tools that the others couldn't.. like i said, though, i could be smoking crack.

[asylvest]

The major adaptation that allowed our ancestor to evolve away from the more general primate grade of adaptation is bipedalism (walking on two feet). Bipedalims predates tools by at least 2 million years. You don't see the first tools in the archaeological record until about 1.8mya while bipedalism had evolved by at least 4mya and some reseach suggest perhaps even earlier. It may be that early human ancestors used tools that would not preserve well (wood instead of stone) and so we simply don't find them. However, Jane Goodall's ground breaking work in the 1960's with the chimpanzee dispelled the idea that humans were the only tool users. Chimpanzees often use tools. The most commonly cited example is the use of small sticks to "fish" termites out of the ground.

[Paul3eb]

..ok, right. and the bipedalism allowed us to actually us the opposable thumbs to develop the tools further since we now had two free hands. my bad.. well then, this whole posting isn't legit, is it?

"One of the characteristics most often identified as being typically primate and having played a role in human evolution is the opposable thumb."

so it didn't do it for us but allowed us to get further. i stand corrected. actually i'm sitting. anyway, thanks, and i apologize to everyone else for the simple fact that i'm an idiot

[allah]

Man Asylvest, you are one of those smart nerds that likes to hang at the lode arent you? That type isnt aloud on this board, only us dumb climber types have the privliage of being on this board.

[Paul3eb]

interestingly enough, i was reading my textbook for evolutionary biology (let me tell ya, it's a blast) and it says this:

Humans have three muscles that chimpanzees lack. Associated with these extra muscles, humans have thicker metacarpals with broader heads. Theses differences in thumb anatomy make the human hand more adept at precision grasping than the chimpanzee hand. Susman argues that the modified anatomy of the human thumb evolved in response to selection pressures associated with the manufacture and use of complex tools.

still have the opposable thumbs, but not quite to our complexity. look at what they can climb. if our thumbs are stronger, i wonder if we can send harder stuff.. something to aim for?

[asylvest]

I think you may be misinterpreting Susman's reseach. While it may be true that modern humans have more muscles in the thumb than do chimpanzees (and if Randal says we have more then I am prepared to believe him), you should not equate more muscles with greater strength. The additional muscles provide greater dexterity (control for fine precision work like making stone tools or possibly clipping quickdraws for a more pertinent example) but not necessarily greater strength for climbing activities and I would guess Susman would not back such an argument. I think you have a hard time making an argument that humans are better climbers than chimpanzees considering the innumberable climbing adaptations in their post-cranial anatomy. These features include curved phalanges (finger bones that a perminately hook-shaped), cranially oriented glenoid fossa (shoulder joints) making arm hanging more efficient, significantly larger upper body muscle mass, funnel shaped thoracic cavities (moving the shoulders closer to the midline) and forelimb gripping strength that vastly surpasses modern humans (consider that chimps' forearms are probably at least 3 times as large as humans of comparable body size), and they have a higher humero-femoral index facilitating climbing. These are not even my arguements but rather Susman (and his colleagues Stern and Jungers at SUNY StonyBrook). Overall the chimpanzee anatomy has a much greater facility for climbing as this is one of their main forms of locomotion while our own lineage had abandoned the trees (and climbing until the very recent) for some 5+ million years.