From: Dace (edace@earthlink.net)
Date: Fri 20 Feb 2004 - 00:08:22 GMT
> From: Chris Taylor <christ@ebi.ac.uk>
>
> >>>>*An* organism (individual) is stuck with the form it has.
> >>>
> >>>An organism is a living form that's stuck with a particular set of
molecules
> >>>(though, over time, it undergoes a complete changeover of molecular
> >>>constituents). An individual is a materialization of a collective
form.
> >>>What evolves is not the materializations but the form.
>
> No. The 'form' is effectively little more that the mapping used by
> selection to examine the ability of a set of alleles to act together,
> and to respond appropriately (in concert with the rest of the cell for
> which they are in large part responsible) to irritants.
Form is shape, structure, and function. Evolution is changes in form that
are passed on to future generations. Hence Darwin's preferred term,
"transformism."
> >>>However, as Darwin emphasized, evolution is propelled forward by
adaptations made by
> >>>individual organisms.
>
> Aargh -- adaptations _MANIFESTED_ in individual organisms, _'made'_
> before they were even conceived. Deliberate and diabolical Ted.
Darwin argued that organisms are capable of making morphological adaptations
in youth and then passing on these adaptations as adults to their offspring.
He speculated that flat-fish gained their unusual eye position because their
ancestors pushed their eyes up in their youth when their skulls were still
relatively soft. They distorted their anatomy and passed on the distortion
to their young. (Darwin, The Origin of Species, Modern Library, 1993/1859,
p. 292).
> Where are the tradeoffs in bears
> to account for the cetaceans? I can show you them the other way around
> (i.e. what remains of the bear in the whale),
Darwin cited a black bear swimming with its mouth open to catch insects as a
hypothetical example of how evolution or "transformism" takes place. "As we
sometimes see individuals following habits different from those proper to
their species... we might expect that such individuals would occasionally
give rise to new species." (p. 224) "A strictly terrestrial animal, by
occasionally hunting for food in shallow water, then in streams or lakes,
might at last be converted into an animal so thoroughly aquatic as to brave
the open ocean." (p. 282)
Darwin found a great deal of evidence for inherited adaptations in
domesticated species. "Changed habits produce an inherited effect, as in
the period of the flowering of plants when transported from one climate to
another." (p. 29) Plants don't have to wait for a genetic mutation to tell
them to bloom earlier or later. They simply adapt and pass on their
adaptations to future generations. Because domesticated ducks walk more and
fly less, they develop heavier leg bones and lighter wing bones than their
wild counterparts. It's not just their muscles, which could adapt in their
lifetime, but their bones, whose development is in-born and thus inherited
from their domesticated ancestors. He notes that domesticated chickens have
no fear of dogs and cats (p. 326). Are we to assume a genetic mutation
eliminated this fear? Or did chickens simply realize they had nothing to
fear from dogs and cats, and this knowledge was inherited by future
generations? He notes that young dogs of a certain breed will point,
retrieve, and run around-- rather than at-- a flock of sheep *without
training* (p. 324). They inherited the habit.
The question is, do we direct evolution through our living adaptations that
are passed on to our progeny, or does everything happen blindly, by chance,
in the nuclei of our cells? Is life all about making decisions and adapting
to changes, or is it about chance alterations of genes as they're copied
deep in our cells? For Darwin, there was simply no question about it. A
theory of evolution that fails to recognize the centrality of the organism
as it goes about its day-to-day business is simply not believable.
Every inherited variation has a commonsense explanation on the one hand, and
a convoluted and incredibly implausible explanation on the other hand. And
in every case, we're supposed to believe the implausible explanation. This
is simply not serious, and it's why creationism continues gaining ground.
Certain dogs just happened to undergo a mutation that caused them to run
around sheep instead of at them? And this just happened to occur only to
dogs whose ancestors had been trained to perform this very task and to no
other types of dogs? It's impossible to believe this regarding even one
example, but to multiply it by millions of species is to strain credibility,
to say the least.
Darwinian evolution depends on two features; one, that individual variations
are inheritable and two, that these features are inherited at the same age
or younger by progeny. "For if each part is liable to individual variations
at all ages, and the variations tend to be inherited at a corresponding or
earlier age-- propositions which cannot be disputed-- then the instincts and
structure of the young could be slowly modified as surely as those of the
adult; and both cases must stand or fall together with the whole theory of
natural selection." (p. 331)
> but there is no feedback
> in this system, to some 'out there' form. Neither can we expect that
> memes should conform to such a Platonic ideal in any sense -- except
> where external factors dictate that form.
Platonic forms exist in an eternal, unchanging state and are therefore
incompatible with Darwinian evolution, aka transformism.
> > The literal meaning of
> > evolve is "unfold," which implies that the newly unfolding form already
> > existed in some ideal, predetermined state. Darwin was a materialist
but
> > not a determinist. He believed in the inherent creativity of matter.
> > Evolution is all about creative adaptations among individuals that lead
to
> > transformations of whole populations into new species.
>
> Darwin would've loved a Lamarckian mechanism, but Lamarck's mechanism
> is not as robust as the 'Darwinian' alternative
We know Weismann's "Darwinian" view was wrong because genetic mutations take
time, and inherited adaptations pop up in domesticated species in only a few
generations. But we know Darwin's "Lamarckian" view was wrong as well
because he thought there was some kind of material means by which
adaptations were conveyed from parent to offspring. It turns out phenotype
doesn't affect genotype. So both of the materialistic views are wrong.
This leaves only one option. New adaptations are inherited nonmaterially
and collectively. Rather than parents passing on an adaptation directly to
their offspring, each newborn inherits it from the collective memory pool of
the population to which it belongs.
Darwin was well aware that his materialistic view was problematic. He
asked, for instance, how the traits of worker ants are passed along
generation to generation when worker ants don't reproduce? (p. 353) He
considered this to be the single most serious objection to the theory of
natural selection (p. 358). Noting a similar problem in the theory of light
prior to Faraday and Maxwell, he regarded the "undulatory theory of light"
as an example that biologists should follow in overcoming their own
difficulty with evolutionary theory (p. 637). Darwin admired Goethe and
emphasized the importance of a holistic theory of organisms (p. 188). So
it's not such a stretch to conclude that Darwin would have accepted a theory
of inheritance that relies on holistic memory.
> because of the danger
> of overadaptation to ephemeral/local conditions, so you only see
> Lamarckian stuff at the fringes of systems, like clonality (the
> exact opposite).
All evolution is local. Organisms evolve according to local conditions.
> >> Individuals can change (or adjust) during a lifetime to match the needs
> >> imposed by the environment within a reaction norm influenced by their
> >> given genetic repertoire, but they are not evolving.
> >
> > Right. They are merely adapting. Evolution is the inheritance of
> > adaptations.
>
> No. Evolution is the inheritance of chance variations
The question is not whether evolution is primarily about chance variations
but why so many people hold such a patently bizarre belief. Are biologists
simply crazy? As tempting as the notion is, we just reject it. The answer
is to be found, not in psychology, but in memetics. Darwin believed he
could be a materialist about evolution because he didn't know that living
adaptations have no effect on genes. But once the Darwin meme had gotten a
solid footing, it proved impossible to kill off. Darwin himself, had he
lived long enough, would clearly have abandoned materialism so as to save
evolution as a viable theory. But his meme has taken on a life of its own.
Ted
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