On Tue, 27 Aug 2002 11:01:10 -0400, Todd Moody <[log in to unmask]>
wrote:


>You wrote: "'Expensive Tissue' only makes sense if the gut also
>was highly active, at rest. ...
>I think "resting metabolic rate" does not imply that the gut is
>at rest.  The gut is metabolically expensive because it is often
>working hard even when the rest of the organism is resting.

Yes this was my point, all the expensive tissue makes sense if gut is more
active than the rest. One expensive tissue (gut) in exchange for annother
(brain) :-)

What means "at rest"? Maybe at rest, but with something in the stomach,
for these RMR computations, I suppose.
Then at least some parts of the gut move (with muscles) to move the contents
further. The increased energy of a 3-times sized brain would be
some 2/3 of 500kcal. Could the gut spare 350 kcal?
Well, if the rmr is constant it must be the case.

>"Personally I think a improved dietary quality alone can explain
>the gut size reduction. ...
>
>This seems correct.  But you add,
>
>"Increased dietary quality from animals can hardly explain how
>additional energy can come in. Game meat is a energetically a low
>density food, unless it's fat."
>
>This isn't right.  100g of elk (a typical game meat) is 111 kcal;
>110g of yam is 118 kcal.  They are comparable.  I think
>"increased dietary quality" should be understood to come from
>*both* meats and high-density plant foods (where they were
>available).

Yes, as you point out, elks or gazelles would have the same
(increased) DQ as yams. Your point is right.
To digest them both (elks,tubers) would be possible in a similar sized gut
(starch and fat is easy). The protein from the elk should be slower to
digest, but fast enough for 350 kcal more.

But inhowfar is 118kcal actually increased? Fruit is at 50kcal or so, the
but difference is only water. it's easy to twice as much fruit as tubers.

The real difference is availability.
Wrangham's tubers would be much easier and more reliable to "hunt" than
gazelles, I suppose. So that's the argument what's left.

How did you like my venus of Willendorf as a paleo-DHA-attractiveness
demonstration?

Cheers

Amadeus