Reflectorites
On Thu, 17 Aug 2000 00:51:02 -0500, Chris Cogan wrote:
CC>This is one of Stephen Jone's tagline quotations:
>SJ>--------------------------------------------------------------------------
>>"The changes within a population have been termed microevolution, and
>>they can indeed be accepted as a consequence of shifting gene frequencies.
>>Changes above the species level-involving the origin of new species and the
>>establishment of higher taxonomic patterns- are known as macroevolution.
>>The central question of the Chicago conference was whether the
>>mechanisms underlying microevolution can be extrapolated to explain the
>>phenomena of macroevolution. At the risk of doing violence to the
>>positions of some of the people at the meeting, the answer can be given as
>>a clear, No." (Lewin R., "Evolutionary-Theory Under Fire: An historic
>>conference in Chicago challenges the four-decade long dominance of the
>>Modern Synthesis," Science, Vol. 210, pp.883-887, 21 November 1980,
>>p.883).
CC>Regardless, the empirical fact is that, genetically and morphologically,
>many species differ from each other in ways that amount to collections of
>microevolutionary changes, in the same kinds of ways we'd expect them to
>differ if one species evolved via microevolutionary steps from the other
>(or from a close common ancestor). This does not *prove* microevolution, of
>course.
No one is *denying* "microevolution", not even the ICR!
CC>It just makes ID theory pointless
The above quote has nothing particularly to do with "ID theory". It was a
*1980* meeting of *evolutionists* described as "one of the most important
conferences on evolutionary biology for more than 30 years":
"In many ways this cryptic exchange expressed the prevailing
sense of the participants at one of the most important conferences
on evolutionary biology for more than 30 years. A wide spectrum
of researchers-ranging from geologists and paleontologists,
through ecologists and population geneticists, to embryologists and
molecular biologists-gathered at Chicago's Field Museum of
Natural History under the simple conference title: Macroevolution.
Their task was to consider the mechanisms that underlie the origin
of species and the evolutionary relationships between species."
(Lewin, 1980, p.883)
Attendees mentioned in the article include Stebbins, Maynard Smith, Ayala, Dover, Gould,
Vrba, Raup, Stanley and Kaufmann.
CC>... uuntil there is some *positive*
>evidence that macroevolution is not simply another word for multiple
>microevolutionary steps.
The consensus of attendees at this conference didn't think so. Even the
Neo-Darwinist geneticist conceded that "small changes do not accumulate":
"In a generous admission Francisco Ayala, a major figure in
propounding the Modern Synthesis in the United States, said: `We
would not have predicted stasis from population genetics, but I am
now convinced from what the paleontologists say that small
changes do not accumulate.'" (Lewin, 1980, p.883)
This of course is absolutely *fatal* to Darwinism as a general theory
(although it may not be realised by all Darwinists). Darwin's general theory
is simply the extrapolation to the whole of life, past and present, of
Darwin's special theory:
"Although all Darwin's evidence, even the evidence of geographical
variation, was in the last analysis entirely circumstantial,
nevertheless, the arguments and observations he assembled in the
first five chapters, as well as in Chapters Twelve and Thirteen,
enabled him to build a very convincing case for his special theory -
that speciation, the origin of new species from pre-existing species,
can, and does, occur in nature as a result of perfectly natural
processes in which natural selection plays a key role. If the Origin
had dealt only with the evolution of new species it would never
have had its revolutionary impact. It was only because he went
much further to argue the general thesis that the same simple
natural processes which had brought about the diversity of the
Galapagos finches had ultimately brought forth all the diversity of
life on earth and all the adaptive design of living things that the
book proved such a watershed in western thought. Much of the
Origin, especially the later chapters, dealt not with the special
theory which gave the book its title, but with a defence of its
general application. One of the key arguments Darwin advances,
and one to which he returns at least implicitly in many places in the
Origin, is that once it is conceded that organisms are inherently
capable of a considerable degree of evolutionary change, then might
they not, especially if a great length of time is allowed, be
potentially capable of undergoing practically unlimited change
sufficient even to bridge some of the seemingly most fundamental
divisions of nature?" (Denton M.J., "Evolution: A Theory in
Crisis," 1985, pp.46-47)
Darwinism, as a general theory depends on the assumption that all children
have parents by the normal process of reproduction, as Dawkins recently
pointed out:
"Similarly, it follows from evolution that if all the hominids who
ever lived were available to us in a gigantic fossil museum, all
attempts to segregate them into nonoverlapping species or genera
would be futile. No matter how richly branched the evolutionary
tree, every fossil would be indirectly connected to every other by
unbroken chains of potential intermarriage. The only reason we can
indulge our penchant for discontinuous names at all is that we are
mercifully spared sight of the extinct intermediates. In the case of
living animals, we see only the tips of the evolutionary twigs. For
paleontologists, the mercy is that so few individuals fossilize. We
may believe that the genus Homo is descended from the genus
Australopithecus. But it is ludicrous to suggest that there must once
have been a Homo child at the breast of an Australopithecus
mother. It necessarily follows from the fact of evolution that
discontinuous naming must ultimately break down." (Dawkins R.,
"Branching Out," Review of "Extinct Humans," by Ian Tattersall
and Jeffrey H. Schwartz,, The New York Times, August 6, 2000.
http://www.nytimes.com/books/00/08/06/reviews/000806.06dawkint.html)
Therefore, no matter how discontinuous the process may *look* in the
fossil record, to Darwinists in the end it must just be an *apparent*
discontinuity.
But once Darwinists conceded (as they did at the above Chicago 1980
Conference) that the discontinuity between the processes observed at the
micro and macro levels is *real*, then Darwinism as a general theory is
dead, and only Darwin's special theory, as an explanation of
microevolution, is left.
In fact in the same year Gould actually wrote that Neo-Darwinism was
"effectively dead, despite its persistence as textbook orthodoxy":
"I well remember how the synthetic theory beguiled me with its
unifying power when I was a graduate student in the mid-1960's.
Since then I have been watching it slowly unravel as a universal
description of evolution. The molecular assault came first,
followed quickly by renewed attention to unorthodox theories of
speciation and by challenges at the level of macroevolution itself. I
have been reluctant to admit it-since beguiling is often forever-but
if Mayr's characterization of the synthetic theory is accurate, then
that theory, as a general proposition, is effectively dead, despite its
persistence as textbook orthodoxy." (Gould S.J.,
"Is a new and general theory of evolution emerging?"
Paleobiology, Vol. 6, No. 1, January 1980, p.120)
Moreover, since then even Dawkins has had to admit that at least some
children must have been *markedly* different from their parents:
"But are there any very special occasions when saltations, or
macromutations, are incorporated into evolution? Macromutations
certainly occur in the laboratory. Our theoretical considerations say
only that viable macromutations should be exceedingly rare in
comparison with viable micromutations. But even if the occasions
when major saltations are viable and incorporated into evolution are
exceedingly rare, even if they have occurred only once or twice in
the whole history of a lineage from Precambrian to present, that is
enough to transform the entire course of evolution. I find it
plausible for instance, that the invention of segmentation occurred
in a single macromutational leap, once during the history of our
own vertebrate ancestors and again once in the ancestry of
arthropods and annelids. Once this had happened in either of these
two lineages, it changed the entire climate in which ordinary
cumulative selection of micromutations went on." (Dawkins R.,
"Darwin Triumphant: Darwinism as a Universal Truth," in
Robinson M.H. & Tiger L., eds., "Man & Beast Revisited," 1991,
p.31).
CC>In short, it has to be shown that the idea of
>macroevolution can be *relevantly* distinguished from microevolution. So
>far, all we have are *assertions* to this effect. If macroevolution simply
>*is* microevolution repeated a few times, ID theory loses its primary
>alleged reason for being.
Again, it has nothing here to do with "ID theory". It is a debate within
naturalistic evolution theory itself.
CC>Since repeated (*cumulative*) microevolution is readily observable in the
>lab and in Nature,
It may be significant that Chris capitalises "Nature"?
CC>just what *is* the point of ID theory? Are ID folk
See above. The above quote had nothing to do with "ID theory" and
"ID folk". It was by *evolutionists*!
CC>claiming that there is some *limit* on the number of times microevolution
>can occur on one genetic subtree?
Chris has perhaps unintentionally revealed the `trade secret' of
macro-Darwinism, which is the hidden premise of *no limit* below:
1. All organisms vary [WITHOUT LIMIT];
2. Some of those variations are more favourable than others in a given
environment;
3. Some of those favourable variations are inheritable;
4. More organisms are born than can survive to reproduce;
5. Those organisms possessing favourable inheritable variations will pass
on those favourable variations to their offspring;
6. GOTO 1
But take out the hidden "without limit" assumption in premise 1 and all you
have is a homeostatic tendency to equilibrium, i.e.:
"homeostasis ... a relatively stable state of equilibrium or a tendency
toward such a state between the different but interdependent
elements or groups of elements of an organism, population, or
group..."
(http://m-w.com/cgi-bin/dictionary?book=Dictionary&va=homeostasis)
which is in fact what we observe in the actual empirical evidence for
Darwinism, namely peppered moths and finch-beaks on the Galapagos!
There is in fact no empirical evidence that organisms can vary without
limit. If that was the case, common descent itself would be unverifiable,
because what looks like a homologous relationship in the fossil record
could just be a case of another, unrelated species, just happening to vary
without limit in the time interval between them.
Even the strongly evolutionist plant breeder, Luther Burbank admitted
there were limits beyond which his seelctive breeding programs could not
go:
"Luther Burbank who, though no theoretician, was the most
competent breeder of all time, looked at this problem. He
eloquently endorsed the limited charter:
`There is a law...of the Reversion to the Average. I know from my
experience that I can develop a plum half an inch long or one 2 1/2
inches long, with every possible length in between, but I am willing
to admit that it is hopeless to try to get a plum the size of a small
pea, or one as big as a grapefruit. I have daisies on my farms little
larger than my fingernail and some that measure six inches across,
but I have none as big as a sunflower, and never expect to have. I
have roses that bloom pretty steadily for six months in the year, but
I have none that will bloom twelve, and I will not have. In short,
there are limits to the development possible, and these limits follow
a law. But what law, and why? It is the law that I have referred to
above. Experiments carried on extensively have given us scientific
proof of what we had already guessed by observation; namely, that
plants and animals all tend to revert, in successive generations,
toward a given mean or average. Men grow to be seven feet tall,
and over, but never to ten; there are dwarfs not higher than 24
inches, but none that you can carry in your hand.... In short, there is
undoubtedly a pull toward the mean which keeps all living things
within some more or less fixed limitations' (Burbank L., in Hall W.,
ed., "Partner of Nature", Appleton-Century, 1939, pp.98-99).
(Macbeth N., "Darwin Retried: An Appeal to Reason," 1971, p.36)
CC>If so, what is the *evidence* that there
>is any such limit,
See above. There is *plenty* of evidence that there is such a limit. But
from Darwin's time on, the Darwinists have simply *assumed* there is no
limit:
"Slow though the process of selection may be, if feeble man can do
much by artificial selection, I can see no limit to the amount of
change, to the beauty and complexity of the co-adaptations between
all organic beings, one with another and with their physical
conditions of life, which may have been effected in the long course
of time through nature's power of selection, that is by the survival
of the fittest." (Darwin C.R., "The Origin of Specie," 6th Edition,
1928, reprint, p.104)
He even used the rhetorical trick of trying to reverse the burden of proof:
"In order that any great amount of modification should be effected
in a species, a variety when once formed must again perhaps after a
long interval of time, vary or present individual differences of the
same favourable nature as before; and these must be again
preserved, and so onwards step by step. Seeing that individual
differences of the same kind perpetually recur this can hardly be
considered as an unwarrantable assumption. But whether it is true,
we can judge only by seeing how far the hypothesis accords with
and explains the general phenomena of nature. On the other hand,
the ordinary belief that the amount of possible variation is a strictly
limited quantity is likewise a simple assumption." (Darwin, p.84)
But since uniform experience is that there *are* limits to biological change,
both in the breeding-pens and in the wild, it is up to the Darwinists to
support their claim with evidence that there is no limit to change.
CC>and just how many times *can* a genetic subtree exhibit
>microevolution before microevolution comes to a halt? And just what is it
>that forcibly prevents *further* steps of microevolution from occurring?
Note how Chris words it. It is assumed that "microevolution" will keep
"occurring" *without limit* unless something "forcibly prevents".
Then if nothing can be found which "forcibly prevents" "microevolution"
from "occurring" *without limit*, then it is simply assumed that
"microevolution" *does* keep "occurring" *without limit*.
But apart from the fact that there *are* plenty of mechanisms which
prevent unlimited change, there is nothing even within Darwinism major
premises that would predict unlimited change. All that Darwin's major
premises would predict is that species would tend to track their local
environment. And since their local environment is largely cyclical, all that
Darwinism would predict is fluctuating cyclical variations around central
mean.
It is Darwin's *hidden* "no limit" premise that transforms Darwinism from
an empirical scientific theory of microevolution (micro-Darwinism) into a
speculative general theory of macroevolution (macro-Darwinism).
CC>What *keeps* populations of one species from evolving into other species if
>environmental conditions are favorable to such evolution? Why don't we see
>horrendous and insurmountable *stoppages* of further genetic variations as
>microevolutionary steps accumulate, and *regardless* of the biological
>advantages that such further steps would provide for the organism and the
>genomes involved?
Notice how Chris uses overblown *rhetoric* ("horrendous and
insurmountable *stoppages*") to get over the evidentiary `hump'!
CC>Why were humans able to breed (mostly by chance) broccoli
>*and* cauliflower *and* brussels sprouts *and* cabbage from the same
>initial plant?
Chris does not *know* this was "mostly by chance". To breed something
requires detecting small changes, crossing it with something else with
similar small changes, and protecting their offspring from breeding back
with the rest of the population. This would have to continue with
unremitting vigilance for hundreds, if not thousands of years, until enough
genetic changes have occurred between the parent and the new child
species that they cannot interbreed.
CC>Why didn't the limitation on microevolutionary steps prevent
>this from happening?
That there is some freedom to vary within lower taxonomic categories
(does not mean there are no limits at all). In the case of "broccoli *and*
cauliflower *and* brussels sprouts *and* cabbage" they are just varieties
within the *one species*, namely Brassica oleracea:
" ... cabbage vegetable and fodder plant the various forms of which
are said to have been developed by long cultivation from the wild,
or sea, cabbage (Brassica oleracea) found near the seacoast in
various parts of England and continental Europe. The common
horticultural forms of Brassica oleracea may be classified according
to the plant parts used for food and the structure or arrangement of
those parts: (1) leaves: loose or open foliage (kale and collards) and
leaves folded into compact heads (large terminal heads--e.g.,
common cabbage and savoy cabbage--and small axillary heads--
e.g., Brussels sprouts); (2) flowers and thickened flower stalks:
flowers little or not modified (sprouting broccoli) and flowers much
thickened and modified (cauliflower and heading broccoli); (3)
stem: much expanded to a bulbous structure (kohlrabi)."
http://www.britannica.com/bcom/eb/article/0/0,5716,18720+1+18434,00.html
CC>And, of course, if this can happen simply because people in different
>places and times preferred to grow plants with more of some features and
>less of others, why can't similar "selection" occur in nature, via climate,
>predation, nutrient availability, and so on?
More rhetoric ("why can't..."?"), which, ever since Darwin has been typical
of Darwinists when they need to get over an evidentiary hump!
The scientific question is not the rhetorical "why can't...?" but the empirical
"what *evidence* is there for...?".
CC>Since pleiotropism and genetic
>cross-linkages are obviously not enough stop microevolution in its tracks,
Notice how Chris just *assumes* that "microevolution" *has* any "tracks",
i.e. it is a directional process of change that will keep on going unless
something stops it. The way Chris words it, the breeders' job would be
simply to remove obstacles and microevolution would continue on its
existing trajectory of unlimited change. But the fact is that breeders must
work hard to make what limited change they do make.
CC>just what *does* prevent microevolution from going that one more step and
>becoming macroevolution?
Leaving aside the question-begging "one more step", again there is the
hidden assumption that "microevolution" would, if it was not prevented, go
on and become "macroevolution".
The fact is that there is nothing in the processes of "microevolution" that
would lead one to think it *would* go on and become "macroevolution".
It is only the hidden philosophical assumptions that: 1) change is without
limit, when all that Darwinism predicts is local homeostatic equilibrium;
and 2) microevolution is some mysterious force that would continue on a
trajectory if it was not prevented from doing so.
CC>Without strong answers to the core questions here (such as what evidence
>there is that there *is* a real limit on microevolutionary steps), ID
>remains just another scientifically superfluous crackpot theory promoted
>almost entirely for religious reasons.
In this case "ID" has nothing to do with it. The realisation that "there *is* a
real limit on microevolutionary steps" was the consensus position reached
back in *1980* at that Chicago conference, based on the "evidence":
"Evolution, according to the Modern Synthesis, moves at a stately
pace, with small changes accumulating over periods of many
millions of years yielding a long heritage of steadily advancing
lineages as revealed in the fossil record. However the problem is
that according to most paleontologists the principal feature of
individual species within the fossil record is stasis, not change. No
one questions that, overall, the record reflects a steady increase in
the diversity and complexity of species, with the origin of new
species and the extinction of established ones punctuating the
passage of time. But the crucial issue is that, for the most part, the
fossils do not document a smooth transition from old morphologies
to new ones. "For millions of years species remain unchanged in the
fossil record," said Stephen Jay Gould, of Harvard, "and they then
abruptly disappear, to be replaced by something that is substantially
different but clearly related." (Lewin R., 1980, p.883)
If there is a "scientifically superfluous crackpot theory promoted almost
entirely for religious [i.e. *anti*-religious] reasons" it is the sort of
unlimited micro-Darwinism espoused here by Chris!
Steve
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"This generalized proposition-that processes of chance and natural law led
to living organisms emerging on Earth from the relatively simple organic
molecules in 'primordial soups'-is valid only if there is a finite probability of
the correct assembly of molecules occurring within the time-scale
envisaged. Here there is another great problem. In the above example for a
relatively small protein of 100 amino acids, selection of this correct
sequence had to be made by chance from 10^130 alternative choices. The
operation of pure chance would mean that within a maximum of about 500
million years (or somewhat less), the organic molecules in the 'primordial
soup' might have to undergo 10^130 trial assemblies to hit on the correct
sequence. The probability of such a chance occurrence leading to the
formation of one of the smallest protein molecules is unimaginably small.
Within the boundary conditions of time and space which we are
considering, it is effectively zero." (Brooks J., "Origins of Life," Lion:
Tring, Hertfordshire UK, 1985, pp.84-85).
Stephen E. Jones | sejones@iinet.net.au | http://www.iinet.net.au/~sejones
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