On Tue, 17 Jun 1997 11:02:22 -0500, john queen wrote:
>JQ>What amazes me is the lack of discussion of the effects of random
>mutations on the genome. Natural selection is named as proof but even this
>makes no sense. Even if there were were some favorable mutations by random
>chance, what about the non-favorable mutations? If we say these did not
>happen or somehow dont count then we are fooling ourselves. New
>generations (using the evolutionist models) would only provide more
>opportunities for random mutations.
Yes. The original Neo-Darwinian idea was that mutation and
selection happened in large populations and the whole population
gradually evolved into something new. But then when that was
shown not to work, Darwinists switched to a small inbreeding
population model. But the obvious problem with inbreeding is that,
given the proportion of unfavourable to favourable mutations, it
would be more likely to produce a more unfit population:
"A final note in regard to speciation by peripheral isolates involves
their survivability. Mayr reflects that 95-99 percent of all peripheral
isolates will go extinct before ever completing the speciation process.
(Mayr E., "Populations, Species, and Evolution", 1970, p294).
Survivorship is obviously not very good. Though there are a number
of random factors that could be involved, the key factor is that the
population is particularly vulnerable in the midst of the genetic
revolution. This period of revolution would be an extremely
vulnerable time. Even once the speciation process is complete,
survivorship would not be expected to be very great, since the
population would probably be adapted to a rather unique and limited
environment that increases the probability of extinction by stochastic
events. The percentages are reduced even further. Consequently, not
only is the discovery of an intermediate peripheral species in the fossil
record unlikely, but the overall prospects of survivability of the
peripheral isolate and the reality of a genetic revolution would seem
vanishingly small." (Lester L.P. & Bohlin R.G., "The Natural Limits
to Biological Change", 1989, p136).
Breeding experiments confirm that inbreeding depletes genetic variability,
instead of building it:
"Ernst Mayr reported on two experiments performed on the fruit fly
back in 1948. In the first experiment, the fly was selected for a
decrease in bristles and, in the second experiment, for an increase in
bristles. Starting with a parent stock averaging 36 bristles, it was
possible after thirty generations to lower the average to 25 bristles,
"but then the line became sterile and died out." In the second
experiment, the average number of bristles was increased from 36 to
56; then sterility set in. Mayr concluded with the following
observation: `Obviously any drastic improvement under selection
must seriously deplete the store of genetic variability...The most
frequent correlated response of one-sided selection is a drop in
general fitness. This plagues virtually every breeding experiment.'"
(Mayr E., "Animal Species and Evolution", 1963, p290, in Bird W.R.,
"The Origin of Species Revisited", 1991, Vol. I, p125).
Natural selection therefore acts as a brake on evolution! That's why
the central feature of the fossil record is stasis, noot change. But no
doubt some minor variation within the type occurs (95-99% is not
100%), but what gets through this sieve is just microevolution. It is
difficult to see major body-plan changes occurring this way, unless
they were supernaturally guided and protected, according to a plan:
"To explain the appearance of new body types, a mechanism capable
of generating not piecemeal change, but integrated, systemic change
(affecting an organism's overall physical structure) seems to be
needed. Minor changes caused by recombination of genes and by
mutation may be acted upon by natural selection to fine-tune an
organism, enabling it to fit better within its ecological niche. But no
amount of fine-tuning of its current body plan will produce a new
body plan. In creating a new organism, as in building a new house,
the blueprint comes first. We cannot build a palace by tinkering with a
tool shed and adding bits of marble piecemeal here and there. We
have to begin by devising a plan for the palace that coordinates all the
parts into an integrated whole. Darwinian evolution locates the origin
of new organisms in material causes, the accumulation of individual
traits. That is akin to saying the origin of a palace is in the bits of
marble added to the tool shed. Intelligent design, by contrast, locates
the origin of new organisms in an immaterial cause: in a blueprint, a
plan, a pattern, devised by an intelligent agent." (Davis P. & Kenyon
D.H., "Of Pandas and People", 1993, p14).
What is needed for macroevolution (the generation of something
genuinely new), is an increase in genetic information, and
microevolutionary processes do not provide that:
"Macroevolution requires an increase of the gene pool, the addition
of new genetic information, whereas the means to speciation
discussed above represent the loss of genetic information. Both
physical and ecological isolation produce varieties by cutting a small
population off from its parent population and building a new group
from the more limited genetic information contained in the small
population. A large population carries a genetic reserve, a wealth of
concealed recessive genes. In a small group cut off from the parent
population, some of these recessive traits may be expressed more
often. This makes for interesting diversity, but it should not blind us
to the fact that the total genetic variability in the small group is
reduced. The appearance of reproductively isolated populations
represents microevolution, not macroevolution. It is one of the ways
in which horizontal diversification can occur. To use our earlier
illustration, it is a mechanism for the flowering of a branch in the
evolutionary tree, not for establishing new branches. Vertical change-
to a new level of complexity-requires the input of additional genetic
information. Can that information-the ensembles of new genes to
make wrens, rabbits, and hawthorne trees be gleaned from random
mutations? Thus far, there appears to be good evidence that the roles
mutations are able to play are severely restricted by and within the
existing higher level blueprint of the organism's whole genome. To go
from a one-celled organism to a human being means that information
must be added to the genetic messages at each step of the way.
Mechanisms for the loss of genetic information cannot be used as
support for a theory requiring vast increases of genetic information.
Speciation is actually akin to what breeders do. They isolate a small
group of plants or animals and force them to interbreed, cutting them
off from the larger gene pool to which they belong. Centuries of
breeding testifies to the fact that this produces limited change only. It
does not produce the open-ended change required by Darwinian
evolution." (Davis P. & Kenyon D.H., "Of Pandas and People", 1993,
pp19-20)
JQ>I do not read much besides medical, chemistry and biochemistry books but I
>will make a point to read this book.
Interesting reading! Are you a doctor?
JQ>Steve, I appreciate the post.
Thanks, I appreciate your encouragement.
God bless.
Steve
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