Re: Could the ability to carry things be the key evolutionary advantage of bipedalism?


Stewart wrote:
Quadrupeds can't effectively carry anything. Standing on the hind
legs, a primate with opposable thumbs could carry things. Bringing
food back to a nesting area, carrying food to a safe place to eat, or
where it could be hoarded for later could all be survival advantages.

This could also improve survivability of the offspring by being able to
bring food to them and letting them stay in safer areas

Has anyone explored this possibility?

Just about every possibility has been explored exhaustively,
- except the right one. The reason I say this is that if the
right one had been found, there would be pretty broad
agreement about it, rather than a pelthorial of different
ideas ranging from the reasonable to the absurd.

What's interesting is that there has been some recent
activity on the most obvious theory: bipedalism is more
efficient than quadrupedalism for going any distance in
a species shaped like a primate (it obviously isn't for an
obligatory quadruped like a cat, dog or cow.)

Energy requirements have been remeasured (it turns out
that the original measurements were in small quadrupeds,
without any primates included). The new measurements
included a number of primates. New calculations have
shown that in a. afarensis, for example, bipedal locomotion
is a whopping 50% more efficient than quadrupedal, and
by the time you get to h.erectus (with the longer legs)
it's up in the 80% range. (Figures from memory).

It's now likely that the climate shift from jungle to open
forest, grassland and rivers was all that was needed.
The term "slippery slope" comes to mind.

I've read the calculation paper within the last 3 months,
but I don't have the reference and I didn't save it. Drat!
It's also heavily mathematical, and quite beyond me
without more work that I want to spend.

John Roth

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