tomhendricks474{at}cs.com (TomHendricks474) wrote in message
news:...
>  Mammals:
> > Here is where the case breaks down quickly.
> > Males and females of every mammal species have 50% of the same
genes in the 
> > child.
> > Yet in every case it is the female who tends and caters to the child. Kin 
> > selection would demand 50/50 care, but it is only "in wolves
and humans, that
>  
> > the male plays an important role in the protection and care of
the mother and
>  
> > child." 
> 
> NAA: 
> 
> This is plain wrong.  But it's a common mistake:  Dawkins, one of the
> main proponents of kin selection, has admitted to making this mistake
> in the past.  Relatedness of an individual to one's self does not
> dictate how much altruism one should donate to that individual. 
> Relatedness merely adjusts direct fitness of relativess into the
> single currency of the inclusive fitness of the focal actor.  Anyway,
> we don't have to go into kin selection theory here as offspring are
> the direct fitness of individuals; promoting offspring survival is
> simply promoting own direct fitness.  If the maternal/paternal care
> asymmetry is bewildering from the viewpoint of kin selection, it is
> even more bewildering from the viewpoint of standard Darwinism: why
> does the male not care about his direct fitness???  The answer is that
> the male and the female are both trying to maximize their own direct
> fitness, and because of reproductive differences, they may do this in
> different ways.  Lets say the female has a maximum of one offspring in
> every breeding season.  If she cares for it alone, it has probability
> 0.5 of survival.  If she and the father lend no care, it has
> probability 0.01 of survival.  She has this single offspring to
> consider, so unless the care is extremely costly, she should be
> expected to look after the child.  Now consider the father: should he
> join in with mother in giving parental care, raising the child's
> survival from 0.5 to, say, 0.9, or should he go off and mate with more
> females to have, on average, N more offspring.   If Nx0.5 > 0.9, then
> he should desert.  This is why the female is often left holding the
> baby.  Trivers explained all this 30 years ago, and Dawkins updated
> the argument in the Selfish Gene (1976).
> 
> TH:
> This is a cop out. The genes are 50/50. Kin selection says 50-50 attention.

Where does kin selection 'say' "50-50 attention"?  I have explained
that this is a fallacy.  If you are too put off by mathematics to look
at the appropriate literature (i.e. the work of Hamilton et al, rather
than popular science books) then there is a nice paper by Dawkins
which contains little/no mathematics and which clears up alot  of
these issues.  I don't have the citation at hand, but the title is "12
misunderstandings about inclusive fitness" or some such.  Alan Grafen
also had an amusing article in Nature in the mid 80s or so.

> This is fudging the rule to fit the facts. It is a reach - it is what you do to
> push an idea past its usefulness. 

What rule?  Hamilton's rule?  Hamilton's rule holds, as i have
explained above.  But you don't have to drag Hamilton's rule into this
unless there are weird parental asymmetries in relatedness to
consider.  Consideration of progeny as direct fitness suffices.

> Yes, the above helps explain the problem, but it doesn't support kin selection
> IMO.

And it doesn't argue against kin selection either.  If the parents are
unrelated, then the only relatednesses which come into play are the
relatednesses of the progeny to each of the parents.  But we don't
even have to invoke kin selection, as the progeny counts as direct
fitness of each of the parents.
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