Re: questions from first read of Lucy

J. Moore (j#d#.moore@canrem.com)
Thu, 14 Sep 95 14:41:00 -0500

KMK> finally read lucy and have some q's...

KMK> 1) the description of the K-Ar tests makes me wonder -- won't the
KMK> burning of some of the crystal, in order to release the Ar, also
KMK> release some K as well ?

It doesn't matter that potassium (K) will (presumably) be released.
What they're checking is the amount of argon (Ar) that's in the
potassium-40. The potassium-40 is a radioactive isotope of
potassium which breaks down into argon. As the sample ages, more
and more of it changes from potassium-40 into argon. So the more
pure the potassium-40 is (less argon) the less it has broken down
and therefore the older the sample is.

KMK> 2) dart's hypothesis that early humanoid killers were right-handed
KMK> makes me wonder about the evolution of "handedness." do other animals
KMK> show a preference for either hand/foot. i would imagine it is a result
KMK> of the brain splitting in half, but want to know more...

Seems to be. There's a good book out called *The Left-Hander
Syndrome*, by Stanley Coren (Pysch Prof at UCB) and he's pretty
convincing about handedness resulting from brain assemmetry.
He cites studies of some other animals showing that in cats,
rats, mice, and monkeys, generally a little over 50% of the animals
show handedness, but of those that do show handedness, it's about
evenly split between right- and left-handedness. In humans 90%
show handedness, and about 91% are right-handed. (Of
left-handers, some are actually right-brain dominant [as opposed
to right-handers, who are left-brain dominant] but others are
left-brain dominant like right-handers, and their left-handedness
apparently results from stress to the child during development,
which also correlates with problems such as allergy-senstivities.)

KMK> 3) have any fossil chimps been found since Lucy was written? is there
KMK> a general reason for this?

Here's what I wrote on that subject just a few weeks ago:

The answer is almost certainly habitat. If, as seems likely, they
lived in forests like they do now, well, that's a horrible place to
be if you want to end up fossilized. ;-) Problem is you rot, and
little bugs and whatnot eat you, and you don't get covered up by
sediment or volcanic ash, which are topnotch ways to get
fossilized. Animals which spend a great deal of time in, for instance,
mud flats or shallow water get fossilized at one hell of a rate.
That's why there's so many fossil pigs in Africa that they can be
used to check dating processes, as I mentioned in a post on the
Dating of 1470.

This effect of environment of the likelihood of fossilization
would seem to be why we find more hominid fossils than fossils of
proto-chimps and proto-gorillas. It also would seem to be why
you don't find as many hominid fossils as you do pigs.

Since I wrote the above someone has pointed out that animals which
die in savannahs (mixed forests and plains, or plains, or shrub and
plain -- there are different types of savannah, despite what some
people try to get you to believe) also get scattered and eaten,
etc., which they do, but they don't get quite so intensively
attacked by the little guys that really do in bone -- mice,
say, and *especially* micro-organisms, which thrive in moist dense
forest, which is the primary ape habitat.

KMK> would appreciate responses...
KMK> --k

Sorry I couldn't reply sooner; I wanted to wait until I went
round to the library so I could double-check a couple of the
answers.

Jim Moore (j#d#.moore@canrem.com)

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