Re: Faithful Ancestors was Re: Doesn't ANYONE have anything new to say?

rmacfarl wrote: 

Lorenzo L. Love wrote:
...

I had this long diatribe about the June 11 article in Science News
about sexual dimorphism in A. afarensis and how Owen Lovejoy is the
smartest person in the field because he said what I've been saying
for years that the dimorphism is wildly over estimated in a self
fulfilling prophecy of assuming big bones are male and small bones
female. But the damn computer crashed and I lost it all and I don't
have the energy to try to re-create it.

Lorenzo L. Love 


http://dept.kent.edu/anthropology/love.html
...

Note:
"...McHenry's analyses rested on a small number of fossils that covered
 a time span of at least 500,000 years and were unearthed at sites
separated by nearly 500 miles. The specimens could have come from
populations showing a variety of unique male-female anatomical contrasts."

So not a small and isolated group.


But the part I was interested in was:
"Finally, cursed with a scarcity of pelvic remains that could clearly
distinguish wider-hipped females from slimmer-hipped males, McHenry
simply assumed that big bones came from males and small bones came from
 females, Lovejoy says."

The example I use is 6'3" volleyball player/model Gabriele Reese and 5'
nothing actor/director Danny DeVito. If McHenry found their bones after
a few million years of wear and tear, he would declare the big bones
male and the little ones female.


And besides, how valid is this big males equals harems thing? Any of
these people ever see a male orangutan?

Lorenzo L. Love
http://home.thegrid.net/~lllove

"Facts are meaningless. You can use facts to prove anything remotely true."
                            Homer Simpson



Nice pickup. However I'm not in your camp, or Lovejoy's about sexual
dimorphism. Even when I first read of his food-sharing hypothesis in
Johanson's Lucy's Child, it just struck me as a too anthropomorphic
picture of a still very ape-like animal.

As re orangs, the key point is that male size equals reproductive
access to females. Orangs are polygamous & big males win out in the
race to reproduce. Humans & chimps exhibit less dimorphism, and males
have less success at monoplising access to females (with differing
strategies) than orangs & gorillas.

The only thing that to me argues in favour of less competition between
males is reduced canine size. But I must say when it's so rare to find
a statistically significant sample of fossils from a single species in
a single moment in time, as the First Family appears to be, then
evidence that there appears to be significant dimorphism within it as
persuasive. I stand to be re-educated, but I find Lovejoy's latest
analysis unconvincing and a little too much like "well he would say
that, wouldn't he?"

(And if this doesn't stir up a good verbal stoush, I'm giving up on you
lot as a bad job... :-)

Ross Macfarlane


Significant dimorphism within the First Family? Not according to Lovejoy:
"Whether the First Family included two dozen or only a half-dozen members, males exhibited a moderate size advantage over females, close to that observed in people, Lovejoy's team found."

Since those love them and leave them guys, orangutans, and the faithful and protective good husbands, gorillas, both show similar high levels of dimorphism, what can we conclude about group behavior vs dimorphism? Zip. Both the orangutan model and the gorilla model may provide a sexual monopoly for the male (not so much with gorillas, observation shows lots of females sneaking off into the bushes with the younger males) but the two models are diametrically opposite in regards to group dynamics. So for those who make the poory support claim of high dimorphism, why assume the gorilla model? Because male gorillas seem to be nicer people then the asocial male orangutans who basically rape their wimen folk?

But we have no idea of what the dimorphism is. When two leading researchers take the same data and come up with two such widely diverging conclusions, there is something wrong. Lovejoy's methodology may not be perfect, but McHenry and Plavcan's circular reason is obviously fundamentally flawed.

What does Occam's Razor tell us? As both Homo and Pan have similar moderate dimorphism, what must we assume about the last common ancestor? And for any species in the lineage between that LCA and the present?

Lorenzo L. Love
http://home.thegrid.net/~lllove

“Facts are meaningless. You can use facts to prove anything remotely true.”
                            Homer Simpson

.

Relevant Pages