Name And Address Supplied wrote:

Tim Tyler  wrote in message 
Elaine Jackson  wrote or quoted:


> > From an evolutionary standpoint, how does one explain decrepitude?
> > The same as senescence?  If so, two of the main theories: 
> >  * Disposable soma 
> >    This states that reproductive and maintenance processes compete for 
> >    resources. Reproducing early clearly has many advantages - and is 
> >    consequently somatic tissue maintenance programs do not receive 
> >    sufficient investment to support indefinite survival.   
> >  * Antagonistic pleiotropy  
> >    This theory proposes that genes that delay the expression of 
> >    deleterious genes are favoured.  More generally, it suggests that 
> >    alleles may be favoured if they have beneficial early effects but 
> >    deleterious later effects.

> NAS:-
> The trade-off described by "Disposable soma", as you have described
> it, is equivalent to general "Antagonistic pleiotropy". In both cases,
> variants arise which either promote functioning early or late, and
> early is favoured as here reproductive value is highest.

JE:-
The phrase: "reproductive value is highest" lacks
rigor, yet the entire argument depends on it.

The reproduction of exactly what from what?
Unless NAS can provide the missing maximand
of his argument he/she is just attempting to substitute 
his/her "hand waving" measure of fitness for 
a refutable Darwinian view of fitness.

Regards,

John Edser
Independent Researcher

PO Box 266
Church Pt
NSW 2105
Australia
edser{at}tpg.com.au
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