Bill writes with great accuracy and fidelity:

>I would think that high fidelity is not necessary for life. However, 
>high-fidelity information transfer will rapidly replace lower fidelity 
>information transfer for exactly the reasons Tim lists.
>
>So it might be more accurate to say that hi-fi transfer is a 
>necessary result of life rather than necessary to life.

It's important to note that although Darwin defined both the mechanisms of
natural and sexual selection, they are signficantly different phenomena.
Natural selection can be said to be the sum of all of the *extrinsic* factors
that determine which of the existing phenotypes survive and reproduce. Sexual
selection is, on the other hand, quite different in that it is clearly
*intrinsic* to lineage, a selection mechanism imposed on itself. If sexual
selection exists, it exists for a very specific purpose. No purposivity can be
attributed to natural selection. It is a natural phenomenon, no different in
causality than the role of gravity in the formation of stars. But that
purposivity clearly exists for sexual selection.

Sexual selection appears to be a mechanism invented within the phyletic lineage
to prevent the transfer of significant congenital errors,
generation-to-generation. Sexual selective pressures reach their peak just
prior to one gender or the other being admitted into the breeding deme. The
rates of infusion of novel error into the germline is not insignificant, but
because this selective filter can be quite intense, and because it operates in
a regenerative fashion, being imposed on every generation, significant
congenital defects can be quickly eliminated from the population.

The raison d'etre of sexual selection is the minimization of phenotypic
wasteage, eliminating the production of non-competitive phenotypes. It is for
precisely this reason, exactly as Bill suggests, populations that accurately
transmit their accrued germline information into their next generations will
rapidly displace those lineages that do not and are marked by increasingly
corrupted genomes. 

Even more than the competitive advantage that sexual selection implies, if the
rate of novel error infusion exceeds a certain preset limit, the evolution of
complexity above that limit becomes impossible. Reproduction must nearly be
replication if the ancient mass of knowledge borne in germline DNA is to be
maintained. That limit is marked by the inequality:

               n u > p

where n is some measure of complexity (at its simplest, merely a count of the
number of genes), u the basal thermodynamic error rate, and p the ploidy
(redundancy) count.

If the quantity nu much exceeds p, then every new phenotype will be burdened
with at least one new defect and no individual will be a perfect basis breeder
for the next generation. Under these circumstances, the lineage will be
condemned to a constant accrual of error with each generation.

Several choices are available to a lineage with this equation. One is to
constrain the level of complexity, not a particularly desirable choice simply
because lessened complexity means a lessened capacity to exploit the
environment in particularly subtle manners. The second choice is to invoke
cell-internal mechanisms of error detection and repair. This later mechanism
can dramatically reduce the effective thermodynamic error rate, u'. If this nu'
quantity can be driven below the p value, sexual selection is now offered the
chance to accurately and effectively discriminate among the various phenotypes
and is allowed to discover that subset of individuals who are without evident
error. The simplest and most assured way to accomplish this goal is to drive
the contenders into a state of metabolic exhaustion just prior to their
admission into the breeding colony.

The maintenance of germline informational integrity not only involves the
invocation of mechanisms to sort out the inevitable "manufacturing" defects
associated with an entropic error imposed on each new generation, but also
demands that anticorruption (antihybridization) mechanisms such as prezygotic
and postzygotic isolating protocols also be evolved.

In the end, populations which invoke these kinds of information protection
mechanisms will prosper all out of proportion to lineages that do not.

Wirt Atmar
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