Well, gang, after sleeping on it and getting some rest, I decided to go
ahead and make a response to one of the threads I'm involved in here.
If/when I have time, I'll try to get around to the others, but can't
guarantee anything. Man alive, I tell ya, there is just getting to be so
much to respond to here on Veg-Raw anymore, don't you all agree? It's
getting pretty amazing.

Okay, Bob Avery and I were debating whether there is any "true positive
adaptation" or evolutionary selective effect regarding behaviors (such as
food choices) that kill only after reproduction. I'll try to be a little
less heavy-handed this time around and not so insulting. (Thanks Martha
Segoe, for pointing this behavior out to me--it was very helpful to hear,
and I do appreciate it. :-) )

>>Bob, this is a common objection, but the overall contention is not
>>supported by thorough evolutionary reasoning--you are leaving out one
>>essential factor: The role of intelligence in longer-lived members of
>>the human species helping to ensure survival of the rest of their
>communalgroup.   [Etc.]

Bob:
>Except for dear departed "Uncle" Herbie Shelton and a few isolated
>cohorts, none of my elders or "relatives" are doing much to ensure my
>longevity, quite the opposite in fact.  Anyway, this has nothing to do
>with my point that there is no selective pressure being brought to bear
>on our genes to adapt to inappropriate food choices.

Bob, there may well be merit to the above if you are suggesting that the
kinship argument does not apply so strongly in modern times since we no
longer live in close-knit communal groups. I haven't thought through all
the ramifications of that yet, but think maybe I would agree. (Evolutionary
effects can sometimes be counterintuitive at first glance until you think
all the steps through, and I am just a layman myself in learning about it.)
On the other hand, if one wanted, thought I am not sure I am prepared to do
so myself, I suppose a case could be argued that rich people stand a better
chance of surviving than those who are destitute, and the largesse of
wealthy families in seeing to it their progeny are set up for life is
well-known. Thus, it might be that the foods that rich people eat stand to
have a better chance of being selected for in our evolution given enough
time. I dunno, but I would at least like to point out the possibility here.

However, I strongly disagree that in evolutionary times the survival aid
that parents provides to their children has had nothing to do with
selective pressures regarding food choices. As I understand how evolution
occurs, the influence of parents on the successful survival of their
progeny *does* affect adaptation to food choices, because of the following:
Even, for example, if the foods which the parents know about that can get
the tribe through lean times *are* out of line with that species' current
food adaptation, if such foods eaten enable them to survive when they would
otherwise die, then the genes of those who *can* survive on those foods
will be passed on to descendants, while others will be culled. This results
in "true positive adaptation."

However, even where this effect is not present, there will still be
adaptation to foods whose effects kill individuals primarily only after
reproduction, as long as at least *some* (however few) are killed off prior
to reproduction, and it doesn't take very many. This brings up your earlier
response below here that generated the above thread I started on kinship:

>True positive adaptation only occurs when
>selective pressures are brought to bear.  For example, if in our society
>hamburger & fries  eaters have  many  more children than raw vegans
>(which is the case), this does not  mean that our species is evolving
>toward being able to thrive on this fare (or, rather, "unfair") because
>there are no selective pressures involved.  Most of the diseases that
>kill SAD eaters occur after they have already reproduced.

I believe I earlier basically implied agreement by accepting your above
analysis  and then launched into the "effect of parents on the survival of
their progeny" line of thought. However, there is a fundamental and
standard evolutionary refutation of this contention that I simply
overlooked, which directly addresses your concern about diseases that kill
mostly after reproduction. Because actually, selective pressures still
apply even when, as you say just above, "Most of the diseases that kill SAD
eaters occur after they have already reproduced."

The key word here is "most." Successful evolution occurs even when only a
very few individuals die before reproduction due to genetic un-fitness to
new, persistent behaviors or changes in environment. Theoretically there
could be one circumstance where your argument would apply, and that is if
*absolutely no one* is killed prior to reproduction due to the new
behavior. But for this to apply, one would have to argue that diseases
which eventually kill after reproduction have absolutely no prior
cumulative detrimental effects whatsoever that might also kill some
individuals before the reproductive years.

Even if only a very few individuals die off before reproduction due to,
say, eating cheeseburgers and fries, it still means those few individuals'
genes are weeded out of the population's gene pool in the subsequent
generation. Under such circumstances--actually I believe this is the *most
common* circumstance in evolution--what happens, then, is that it just
takes a longer time (more generations) for the adaptive genes to begin to
predominate in the population.

There is an equation which quantifies all this:

t = log[Qo/(1-Qo)]/s

where s = the selection coefficient (i.e., selective pressure), and "t =
the number of generations necessary for an advantageous gene to increase
from a gene frequency of Qo to (1-Qo)." (Cavalli-Sforza (1994) The History
and Geography of Human Genes. Princeton, NJ: The Princeton Univ. Press, p.
12)

The textbook example given to calculate timespans for complete adaptation
is to assume how long it would take for a gene to increase from 1% to 99%
prevalence in a population, i.e., to go from from Qo = 1% to Qo = 99% in
the equation above.

I am not sure I understand the equation completely, but I believe the
mathematical value of "s" denotes the percentage difference in survival
rate per generation between those carrying the new advantageous gene
compared to those who don't. The differences in survival rate can be
extremely small and still result in successful adaptation, it's just a
matter of time. For example, if the value of "s" is as little as 0.1% (I
assume this means only 1 extra individual per 1000 survives because of the
new adaptive gene compared to those without it who die, but I am not sure
about that), then the equation gives a timespan of 115,000 years for the
advantageous gene to spread from 1% prevalence to 99% prevalance assuming
25 years per generation (Cavalli-Sforza, p. 13). If "s" = 0.3%, then 38,300
years; if 1%, then 11,500 years; if 3%, then 3,800 years; if 10%, 1,150
years.

>>And what is the alternative? Basically it is creationism.

>That's one alternative; there are others.  It doesn't seem far-fetched to
>me to imagine that this planet was seeded with various life-forms by a
>technologically superior culture from another planet that had mastered
>space travel, for example.  I'm not saying this is what happened (or
>didn't happen), just that there are more choices than evolution vs
>creation.  Or that the primary evolution occurred on Mars, say, and a
>Noah's Ark-type migration occurred sometime in the distant past when that
>environment became unliveable.  Of course you will invoke Occam's Razor
>here, but the simplest explanation for a mystery isn't always the Truth.

True, there are other possibilities one can imagine--I shouldn't have been
so absolutistic. But occam's razor is not required to dismiss ones like the
above. The criterion of a scientific theory is that it be testable.
Otherwise one can spin unlimited theories based on the idea that "anything
at all could happen."

For example, if I wanted to go out on a limb, I could say it doesn't seem
too far-fetched to me suggest there might be a hunk of green cheese on the
dark side of Pluto buried 5 miles below the surface, or that there are mice
on Alpha Centauri that fly upside down hanging from marionette strings
suspended from any planets that might be orbiting the star system. :-)

But what "doesn't seem far-fetched" is a relative thing depending on the
individual. That's why the criterion of science is how testable something
is. I mean, sure, anything could happen. Personally, though, while I admit
the possibility, I don't find the speculation of extraterrestrial origins
reasonable because of the lack of evidence after decades and decades of
paleontological excavations. However, were you to propose a realistic test
for it and could present some substantiated evidence to support your test,
then I might be willing to reconsider. (And it would certainly make life a
lot more interesting, that's fer sure!)

--Ward Nicholson <[log in to unmask]> Wichita, KS