Tiedeuutiset kyseenalaistaa Darwinismia

Hyvä kunto vaikuttaa jälkeläisiinkin.
Ja päihteiden käyttö voi vioittaa seuraaviakin sukupolvia vaikka olisi niiden käytön lopettanutkin.
Samoin säteilyn vaikutuksista saadaan sukupolvien ajaksi periytyviä haitallisia ominaisuuksia.

Stevan Harnad (http://en.wikipedia.org/wiki/Stevan_Harnad) selittää alla, mistä Baldwinin evoluutiossa on kyse: Baldwinin evoluutio toimii aivan samojen luonnonlakien mukaan kuin luonnonvalintakin: kelpoisimpien yksilöiden yleistymisenä.

> From: "Liz Lee"
>
> Dear Stevan,
> Can you explain the difference between Baldwinian evolution and
> Lamarckian? I understand that the latter is based on 2 principles,
> the first being that using any organ increases it's size (OK for
> muscles but difficult to see how it applies to everything). The
> second that supposes acquired characteristics can be inherited - the
> blacksmith's arms being an example. What is the difference between
> this second principle and Baldwinian evolution? Thanks Liz

Hi Liz,

The difference is simple, because Baldwinian Evolution really happens
and "Lamarckian Evolution" cannot. Think of any "trait" -- anatomical or
behavioural -- that can be influenced by what happens during an
organism's lifetime (weight increases if it eats a lot, height increases
if it eats well, muscles grow if you work out, lungs rot if you smoke,
typing speed grows if you practise, number of languages you know
increases with how many you learn, etc.). These traits, which you
acquire over a lifetime, cannot be passed on to your children genetically
(not even good nutrition, strictly speaking, though a malnourished
mother will have malnourished kids, but that's not genetic inheritance,
it's intrauterine environment) because they are not encoded
genetically; they're not part of the blueprint you (or rather your
genes) are passing on. That is because Lamarckian Evolution does not
exist: we cannot pass on ACQUIRED traits. We can only pass on INHERITED
traits.

But we CAN pass on an inherited tendency to ACQUIRE certain traits.

Suppose it is good for monkeys to wash their food (I'm inventing here),
and those monkeys that are the children of mother monkeys who happened
to have first learned, by trial and error, to wash their food, also
learn to wash their food by imitating their mothers. Then the children
that happen to be GENETICALLY slightly better at learning to wash from
Mom could survive and reproduce more successfully than those that are
genetically a bit retarded when it comes to learning and imitation.

With the generations, this winning genetic "head-start" in the form of
better and faster learning OF THAT SPECIFIC TASK can not only be passed
on but can get bigger: it all depends on how much of an advantage it
gives, and of course on whether the variation between individuals is
GENETIC variation (for if it is not, then there is of course nothing
for the Blind Watchmaker to work with!)

So just think of Baldwinian Evolution as Evolution of the ordinary
kind, except that what is evolving, gradually or quickly (depending on
where and what kind of genome we start with) is not the wings or the
fins, but the ability to learn certain specific things that give an
adaptive advantage, such as swimming or speaking.

Now there are examples of dedicated "modules" for quick-learning
certain specific things: The little duckling quick-learns to follow
Mom, the little colt quick-learns to walk, the little child
quick-learns to talk. But apart from such task-specific Baldwinian
modules, there is also a much more general genetic capacity which we
all have -- as reflected in our capacity to learn to read, write, do
maths, etc., which was certainly not selected for in our EEA and
definitely not coded in our DNA.

This general cognitive capacity we have of learning all kinds of
things, old and new, is itself just one huge, general Baldwinian Module
that we all have (to varying degrees). This is our general intellectual
capacity, the thing that IQ tests, and especially the general G factor
that IQ tests share, measure. This is what Stephen J. Gould was talking
when he wrote "The (Mis)Measure of Man." (He does not believe
there is a G Factor: he thinks IQ is all just a lot of specialised
skills plus an ability that you gain from experience rather than from
your genes -- rather like muscle strength, I suppose.)

Baldwinian Evolution, with our general intellectual capacity as its
centre-piece, is simply another way of becoming better adapted, hence
better able to survive and reproduce under as wide and varied
conditions as possible. Just as sexual reproduction gave us an
advantage with more possibilities than asexual reproduction did, from
the flexibility that came with chromosome recombination, so Baldwinian
Evolution and IQ equip us to handle a much huger universe of
possibilities than if we had bet all our genetic money on just one
specific genetic design and whatever its one fixed EEA might have been.