Re: Paper: A critique of directionality theory


"g" <gillawton@xxxxxxxxxxxxx> wrote in message
news:dsjkj2$7q2$1@xxxxxxxxxxxxxxxxxxxxxx


Since when would the author have us think that members of a species, being
in a particular place at a particular time, and having accumulated --
through spiralar changes in their morphology over a series of
fertilizations/reproductions an assortment of capabilities would not be
opportunistic -- NOT avail. Or, conversely, how would a species which,
being in a particular place at a particular time, and having NOT
accumulated -- through spiralar changes in their morphology over a series
of
fertilizations/reproductions a set of capacities for availing themselves
of
some opportunity AVAIL themselves of same, regardless.
The point is, opportunity is as opportunity is. What is an opportunity
for
a ruminant is NOT an opportunity for a non-ruminant. Cows do not choose
to
nourish themselves by sucking blood of other mammals, nor do
sanguinary-dieted bats choose to eat grass. iteoparity or no iteoparity.

Some clarification of above para:

Had no intent here to convey that blood-dieted bats would not INDIRECTLY be
advantaged secondarily by a direct, or primary, new externality advantage to
a bovine herd. A better example would be any plant or animal species that
would not be advantaged primarily nor secondarily, such as, say, milkweed.

Also, had no intent here to downplay the role of iteoparity where it DOES
apply. In commercial fish raising facilities, for example, whatever limits
a wide distribution of spawn donation over the full
reproductive age-range, has been found to be important. In at least one
instance, a pathogen has invaded
that decimated younger fish but would not have killed off older ones. The
facility had been harvesting yearlings and using only yearlings for spawning
the next "batch." Once it was known, following the die-off of its "seed
crop," as it were, fisheries began keeping a "breeding pool" of fish that
were allowed to spawn over the full range of their lives.

Hence, iteoparity undoubtedly has played a "favorable" role in the "survival
game," at some junctures.
But it also vary likely played an "unfavorable" role and various admixtures
of favorable and unfavorable. As to unfavorable, an example is that human
mothers over forty on average give birth to a higher percentage of Downs
Syndrome offspring. Also more geniuses have been born from the
fertilization of a younger female H. sapiens by much a much older male of
the species (but also more handicapped offspring, I suspect. (Also, it
should be questioned whether geniuses, in *every case*, are benevolent in
the use of their cognitive contributions to a population, and whether they
*always* productive of any overall fitness advantage to a population.
Historically some have provided advantages. Most have been misfits. And
some have wreaked havoc.) I do not know of any specific study to support
it..., but I suspect..., that fertilizations involving both female and male
H. sapiens who are at later stages of the reproductive years of each, tend
to produce more genetic copying "errors." And these "errors," or
"mutations" tend to be disadvantageous the majority of the time, and
advantageous only rarely. Also, from a historical point of observation, we
tend to see THE SURVIVORS who tended to get the FAVORABLE mutations and
have brought them forward to now.

This is a fundamental irony: that the very mutations which, for the most
part by far, have been unfavorable to individuals inheriting them have been
the providers of most of the *genetic good stuff* we find on Earth today.

But, at any rate, I only wish to point to the role of iteoparity in
evolution and observe that it can be observed currently to "be a factor" in
"making a difference" in the overall reproduction survival -- of commercial
"crops." It is therefore something to be weighed and utilized in plant and
animal husbandry, where it provides only a "cost benefit" result. As we all
know, domestication of plants and animals DO NOT necessarily confer
advantages in the wild. In fact, cost-benefit manipulations in commercial
husbandry tend to TRADE OFF increased DEPENDENCE upon the manipulator, for
advantage to the manipulator.

But, as to the article in subject, I wish to emphasize that... as to how we
would OBSERVE and MEASURE what were the mixed roles of iteoparity, in the
production of what we can only discern, as through a dark glass, by way of
paleontological evidence (fossils) of many thousands or millions of years
ago... all we can be certain of is that, based on current evidence, the net
effect of iteoparity may very well have been a factor back then, as now.
But what "net change" it may have had upon the minutia of evolutionary clock
ticks is but speculatory.

And let me emphasize most stringently of all that mega-results (including
those which appear to portray patterns of "slow" and "fast" change, or
punctuated equilibrium) should be examined NOT with intent to assign them a
single rationalization as to what MIGHT serve to explain them. Rather we
should focus upon examining each and every rationale we can imagine. For,
no matter who it might offend, I discern a tendency to exist among
biologists to *seize upon* one or another rationale and circle the wagons
around it, rather than taking the more scientific approach of, "Sounds very
feasible; so now what OTHER explanations might we come up with before
deciding which of all possible explanations are among the more likely of
them."

g




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