Re: Haldane's Dilemma and quantitative genetics

Wirt Atmar wrote:
... these models are not at all representative of how
evolution works and have almost no value in advancing
any physical understanding of the evolutionary process.
If I can't be any more blunt and offensive than that,
I don't know how.

I agree. "These models are not at all representative of how evolution
works" They are highly unrealistic -- wildly unrealistic -- all in
favor of evolution. That's what makes Haldane's Dilemma so
interesting.

The evolutionary clock does not run at any where
near a constant speed. Filled ecological niches occupied
by highly coevolved communities are very difficult to invade,
and thus evolution tends to come to almost a dead stop
in such situations.

That's a good point. "... thus evolution tends to come to almost a
DEAD STOP in such situations." And Haldane ignored those situations.
When we include those situations it makes Haldane's Dilemma worse.

Intense competitive interaction doesn't
allow much change.

That's another good point. "... doesn't allow much change."

Evolution does not occur in a constant-selection
panmictic pool.

That's another great point. "Evolution does NOT occur in ..."

We now have a mountain of evidence that evolution
operates in this way. Small disruptions tend to act
as "diversity pumps," while large catastrophes vacate
sufficient ecological space so as to act as "complexity
pumps."

"Small disruptions" and "large catastrophes [that] vacate sufficient
ecological space" (such as fire, flood, famine, pestilence, meteor
strikes, climate change, etc. -- which eliminate the fit and the unfit)
have a high cost of random loss. And that higher cost must be paid by
the same finite, limited reproductive excess of the species, which
leaves less left-over for paying the cost of substitution -- and that
slows the substitution rate.

But even more striking than that are the global
catastrophes of the Permo-Triassic and Cretaceous-Tertiary,
events which vacated most of ecological space, and thus
removed all "costs" associated with allelic variations for
a bit of time.

The cost of substitution is unavoidable. It cannot be "removed".

Also, "global catastrophes" have an extremely high cost of random loss.
Again, that slows down the substitution rate.


Evolution proceeds when the costs of substitution
disappear, but those costs are never governed by
some internal mechanism, but only by each
phyletic lineage's external competitive milleu.

The cost of substitution does not "disappear" (unless the substitution
rate drops to zero). ANYTIME your scenario claims the substituting
mutations increase (in number of copies, through reproductive means),
it requires extra reproduction rate -- the cost of substitution.

-- Walter ReMine
Haldane's Dilemma
http://SaintPaulScience.com/Haldane/htm


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Relevant Pages

  • Re: Haldanes Dilemma
    ... It clarifies and generalizes the cost concept. ... When stated as generations per substitution, ... _Ecological Genetics_ does the best ... environmental-change scenario is unnecessary and does favor evolution. ...
    (sci.bio.evolution)
  • Re: Haldanes Dilemma - clarifications - and Felsenstein
    ... Cost Theory and the Cost of Substitution -- a clarification" ... theory in the context of the speed of hominid evolution will be ...
    (sci.bio.evolution)
  • Re: Desiderata for a "cost" concept
    ... substitution" or the "cost of evolution" which permits us to place ... an upper limit on the speed of adaptive evolution. ... the cost for one substitution, and we also know the cost for another ... of reproductive excess is needed just to avoid extinction. ...
    (sci.bio.evolution)
  • Re: Haldanes Dilemma
    ... >> years of human evolution. ... >> data goes into a calculation such as this. ... cost theory permits a faster substitution rate. ...
    (sci.bio.evolution)
  • Re: Desiderata for a "cost" concept
    ... substitution" or the "cost of evolution" which permits us to place ... an upper limit on the speed of adaptive evolution. ... fundamental idea of a 'limit' on the rate of substitution. ... to the assumption that the reproductive excess of the fittest types ...
    (sci.bio.evolution)