From: Chris Taylor (firstname.lastname@example.org)
Date: Thu 19 Feb 2004 - 12:26:02 GMT
>>>>>> Evolution does not happen to organisms. They live or die, reproduce or fail.
>>>>> An organism is not just a sack of molecules. What evolves is the form of
>>>>>organisms rather than their material constituents.
>>>>When you are talking about Darwin and evolution, *species* are the level
>>>>subject to evolution. *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.
>>>However, as Darwin emphasized, evolution is propelled forward by adaptations made by
Aargh -- adaptations _MANIFESTED_ in individual organisms, _'made'_
before they were even conceived. Deliberate and diabolical Ted.
>>>Though Darwin had no idea how such inheritance occurs, he
>>>maintained to the end that without this ability to pass on acquired
>>>characters, evolution as a theory is dead on the water. For Darwin, the
>>>organism is the central actor in natural evolution, and I would add that
>>>the same is true of the person in cultural evolution.
>>Individual organisms are the level at which selection operates, but
>>populations are the level at which evolution occurs.
> Yes. As I put it, "An individual is a materialization of a collective form.
> What evolves is not the materializations but the form." As the evolving
> form is collective, it exists, by necessity, across populations.
At the risk of repeating ourselves from many moons ago: Whither the
variety, in a world of 'forms' -- surely that is the recipe for the
worst kinds of trade-offs? All I will tolerate of this sort of thing is
that there are physical constraints in the world that prevent certain
sors of organsims or favour others. Anything else is unproven, for the
very good reason that it is not true. 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), 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.
>>The quick and dirty
>>definition of evolution is ("not again!" they scream from the peanut
>>gallery) 'changes in allelic frequencies within a population over time'.
>>Thus (is this where I insert a Q.E.D.?) evolution requires a group of
>>organisms or *population* and a time period, which can be taken as
>>subsequent generations. Flail around as you will, you are wrong on two
>>counts if you assert evolution happens to individuals.
> Fortunately, I don't. I merely pointed out, echoing Darwin, that the
> individual is the main driving force behind evolution (and not genetic drift
> or mutations).
Sheep and goats (or sheep innards I suppose).
My point being: What do you think makes them 'individuals'?
>>Not only are you
>>ignoring populationns, you are ignoring the generational aspect of
> Not a bit of it. Ironically, Darwin hated the word "evolution" and
> preferred the more descriptive "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, because of the danger
of overadaptation to ephemeral/local conditions, so you only see
Lamarckian stuff at the fringes of systems, like clonality (the
>> 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
No. Evolution is the inheritance of chance variations which did not have
the effect of preventing the organism producing children that similarly
survived to reproductive age [repeat]. Adaptation is a potentially
poisonous shorthand, which I suspect you are using with diabolical
precision :) (cf. 'they are adapting' -- 'they' are not doing any such
thing -- some are unfortunate enough to get the wrong combination of
alleles/genes _for the context_ and therefore represent a dead end for
those instances of those alleles/genes).
You are conflating phenotypic plasticity with heritable variation, and
will no doubt stir in some non-nuclear inheritance examples given chance
(some of which are pseudo-Lamarckian). All fluff though.
To finish, my little campaign; I think we should asap dump 'survival of
the fittest' to be replaced by 'survival of the fit enough'. In itself
an example of epistasis at work -- it seems simple, but the problems
arise when compatibility with other ideas is the issue (especially
nearly neutral drift). Cf. rabbits, foxes and the life-dinner principle:
Chris Taylor (email@example.com)
MIAPE Project -- psidev.sf.net
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