[extropy-chat] Re: intelligent design homework

Tue Aug 9 09:49:05 UTC 2005

On 8/9/05, Robert Lindauer <robgobblin at aol.com> wrote:
>  What we're trying to get at is
> large-scale adaptations on the order of Rhinoceros-elephant splits
> where the early rhino-fant was split into to two "subspecies" with only
> mildly different genetic profiles.   The elephants got trunks, the
> rhinos got horns, say.  At some point, though, some particular
> rhinofant is no longer able to reproduce with its cousins.  There is
> the -chance- that it may be able to reproduce with its siblings.   The
> problem is not the story up to the point of the rhinofant, the problem
> is with the one that can't do it any more and yet manages to take over
> the world.

You continue to show a serious misunderstanding here about the process
of natural selection. Large net genetic differentials accrue within
breeding populations, not individuals. The rhinofant example, requires
that two separate mating pools occur, through environmental changes,
or perhaps geographic separation. The rhinos continue changing
according to their environmental pressures, and the elephants do the
same. Eventually the two populations are unable to interbreed because
of size differential, or chromosomal mismatch, or whatever. There is
no 'one animal' which defines speciation between taxonomic distinct
groups.

> 
> That animal's mutation is 1)  reproduction related and 2)  apparently
> somewhat harmful since they can't reproduce with the rest of the
> eligible population.  They consequently have very, very low chances of
> surviving and mating.  That is to say, we are still left with the very,
> very unlikely and experimentally unverified need for a particular mule.

Again with the mules. Genetic diversity within species exists because
of mutation, and built in differentiating mechanisms like diploid
chromosomal expression(recessive genes, for example). A breeding
population will change, as you have admitted, in response to
environment and activity. Two breeding populations with separate
pressures will go separate ways.

I've given references to you earlier in this thread for observed
speciation where the new species could not breed with the parent
species. You are either uninterested in this, or willfully ignorant.

> The addition of the complication of "over thousands of generations"
> doesn't do anything to remove the problem of the ONE that can't
> reproduce with the rest of the reproductively eligible population
> around it and yet manages to form the next species against the odds.

Many generations are required for genetic changes to express
significant changes. Biologists fiercely argue about the speed at
which evolution occurs, "Punctuated Equilibrium", "Cambrian Explosion"
and similar terms will get you the references.

In a modern and interesting example, take the so called 'brisk biter'
mosquitoes. molestus mosquitoes were separated from their parent
species, Culex pipiens, by the construction of the London Underground
in 1863. They were first studied in 1999, when Byrne and Nichols
showed that they were unable to breed with Culex pipiens, and showed
vastly different behavior. This is fantastically quick for observed
natural evolution, something on the order of 500 generations.

> My scientific scepticism
> says "Exactly what mechanism would be required for that to happen and
> what evidence is there that such a mechanism existed".

The mechanism of natural selection has many interesting evidential
claims. You may wish to peruse them. Fossil evidence is the most
famous, of course, and radio-carbon, geologic strata, ocean sediment
deposit dating all tend to show a wonderful progression of more
complex species over time.

>  Then I'd start
> looking at the microbiology of genes and realize that gene strands that
> isolate an animal from its potential reproductive partners are harmful
> and then I might start looking elsewhere.

Isolating from potential reproductive partners is of course, not the
mechanism of natural selection. A breeding population accrues changes
by preferential mating in higher sexed animals, and simple relative
reproductive fecundity in simpler.

>  I might also look at the fossil record for all the in-between species that we should be 
> finding and when I didn't find them there, I might perservere or I might  thinking about 
> other options. 

This is of course a very silly claim. Let me introduce you just a few
of the most famous transitional fossils that have been found. First,
Archeopteryx, the most famous dinosaur transitional fossil, was found
less than two years after the publication of Darwin's "Origin of the
Species". Archeopteryx is a transitional fossil, showing the descent
of birds from some dinosaurs. It has several subspecies that have been
found, each being more or less towards one side or the other.
Archeopteryx has been the subject of many creationist claims, but it
has stood the test of time, with 8 full specimens of the species
having been found, and several other transitional bird-dinosaur forms
in different stages of development of bird features(most notably the
1996 discovery of a feathered therapod).

Second are more close to home, the transitional human descendants.
Homo Habilis is perhaps the most contentious, with several skeletons
showing various brain sizes, and tooth development. H. Habilis brain
sizes range from 550cc to 750cc, compared to a modern human skull of
1350cc.

My favorite transitional fossils are whales. Whales are fascinating
creatures, that started out as big land mammals, and began living in
shallows and rivers, eventually losing their rear legs, and developing
blowholes instead of nostrils. (most whales still have teeny foot
bones in their tails that aren't connected to anything). Basilosaurus
isis, a whale ancestor who still has well developed legs(but they're
really small and would be useless for walking on land).

> It depends on how dedicated I was to the
> idea.  On the other hand, if I'd gone and found that creating new
> species of animals was easy and likely to happen all the time and also
> found that in fact, outside the laboratory, there were lots of species
> being created all the time, then I'd be impressed with myself.

So glad you mentioned this too. In the laboratory, many species have
been created in controlled conditions, the most common are plants,
whose robust ability to hybridize has surprised many an incautious
scientist.(see recent stories of genetically engineered crops
hybridizing with local weeds to create resistant strains). Most of
these are trivial kinds of crosses, like more robust rubber plants,
and so on, but a few are really fantastic, like a fireweed species,
which polyploidized with itself somehow, creating a new species that
could not reproduce with the original strain(since you like that
speciation test so much., ref:  Mosquin, T., 1967. "Evidence for
autopolyploidy in Epilobium angustifolium (Onaagraceae)", Evolution 
21:713-719)

> Again, I have no problem -imagining- the world in which evolution might
> be true.  I just don't think our level of knowledge of the matter is as
> definitive as you apparently do.  This I think because the biology
> books I've read always manage to throw the monkeys and millenia
> argument around as though species were beachfronts being worn by waves.

Species are pretty transitory in the larger scheme of things. You see
any trilobites around? Save for very long lived things like Sharks
(triassic) particular species rarely stay put. The situation is always
changing. Wolves and dogs(since you seem to like them too) for
example, don't appear in the fossil record more than a few million
years ago, being preceded by ancestors like Cynodictus, dawn-wolf. Why
is that, do you suppose?

> Here's what I'm getting at, which I'm sure you know.  The vast majority
> of mutations produce animals that are not viable - animals unable to
> survive or reproduce because of the handicap of having been -damaged-
> by some mutation.

Mutations and genetic diversity are far subtler, generally than the
genetic disorders you are likely thinking of here. A slightly taller
person qualifies perfectly well for a differentiating factor which may
nudge a reproductive group into a new niche.

>  The likelihood of accidentally producing -good-
> mutations by sheer chance is near nil.

This happens to be true, but it's not important. Genetic diversity
comes from many sources, only one of which is random mutation. Green
eyes, slightly thicker fingernails, a more aggressive potassium
intracellular pump, these all come from the same place, and are more
than enough to select on. The rarity of mutation doesn't matter, so
long as the traits enter the breeding population, either as first-line
changes, or as recessive characteristics that will express under later
conditions.

> The likelihood of then finding another animal with which to reproduce is even less likely as > the diluted mutation is then poured back into the general gene pool of the
> species in question.

The wonderful thing about sex is that we carry twice as many
chromosomes as we need. I don't think you really appreciate what that
does for the carry capacity of traits per organism, per breeding
population. Your arguments only apply to haploid organisms, and do
actually make evolution slightly harder, which is why diploids and
polyploids are so much more common and adaptable.

>  Millions of years ago, the evolutionist tells us, the
> small apes were seperated into two groups somewhere in africa, one
> species lived in arid land, the other tropical.  The arid-land-apes
> developed techniques for survival in their new environment, etc.

Well, it's pretty humble, to be sure, but we do have a few hundred
fossils, of ascending dates, showing this migration and species
change. How would you explain these fossils, particularly the fact
that many of them belong to species that seem to no longer exist? And
are post-dated by other fossils, similar but different, who are
post-dated by other fossils still?

> Well, we get the ones we have, not unusually healthy, not unusually
> unhealthy, we get the mass of, from the point of view of the
> ever-improving genetic force of mutation and selective force, a really
> rather mediocre gene-pool all around.  If this force is as ubiquitous
> as you say, why don't we have super-rats and super-dogs and super-men?

See, this is where I wonder if you're being willfully silly. Of course
they're not 'unusually healthy'. Unusual compared to what? Other
species? Those other species that are acted on by the same forces? We
have rats turning into other things, but we can't necessarily see
which changes will lead to super-rats, and which will simply die out.
Evolution has no end goals, only local reproductive differentials.
Look at all the different species of rats and mice, each in their
environment, with different characteristics. Know that they are
thought to descend from Tribosphenomys minutus. Humans are super,
compared to Homo Erectus, with pitiful brain sizes, and poor running
legs.

> God is a necessary being, not contingent.  Your question is a category
> error like: "what causes there to be a number six?"

This is entirely off-topic, but I have to point out. Your categories
of necessary and contingent are not coherent. What distinguishes
contingent and necessary beings? Well, necessary beings are necessary
by definition, and contingent beings are contingent on other beings
existing. By this definition, you would be justified cutting off the
chain at any point, and calling that necessary. You could call Humans
the uncaused causer, if you weren't interested in investigating any
further behind them. God could be contingent on other beings you have
no way of knowing about, without investigation. Unless 'god' is
semantic, a category which automatically redefines to whomever is
first, in which case, you can ascribe God no characteristics, because
you can never know if you've found the right God.

-- 
Justin Corwin
outlawpoet at hell.com
http://outlawpoet.blogspot.com
http://www.adaptiveai.com