Preponderance of Evidence for
Naturalistic Origins and Evolution of Life
(3 of 3)
(Top Posts - Science - 073102)

[expanded to 4 posts on 031909 - click
the following to access the 4th post]

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Dinosaur Fossils Reveal Evolution's Big Picture,
Says Paleontologist
Date: Posted 6/25/1999

Excerpt: Dinosaur fossils are providing the answers to some
of scientists' biggest questions about evolution, according to
paleontologist Paul Sereno, who has assembled the most up-to-
date picture yet of dinosaur evolution in the 25 June 1999 issue
of Science.

In his article, which is part of Science's special issue about
evolution, Sereno shows how dinosaur fossils hold the clues
to questions such as: How does an upstart group of species
beat out the dominant group? How do organisms develop nifty
new tricks like flying? And how does the breakup of a super-
continent affect the course of evolution? ...

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Butterflies Help Reveal The Source Of Life's Little Luxuries
Date: Posted 1/25/1999

Excerpt: How the elephant got its trunk, the deer its antlers
and the rattlesnake its rattles may seem like disparate questions
of developmental biology, but the origins of these novelties,
according to the genes of butterflies, may have much in common.

Writing in this week's edition (Jan. 22) of the journal Science,
scientists from the Howard Hughes Medical Institute at the
University of Wisconsin-Madison describe a genetic trick that
helps explain the staggering diversity of patterning and color
exhibited on butterfly wings.

The same trick, the scientists suggest, is widely used among
animals and may be one of the underlying mechanisms that
helps explain how new morphological characteristics -- from
teeth and tortoise shells to fur and feathers -- arise through the
course of evolution.

... In the big scheme of animal evolution, according to Keys,
a graduate student in Carroll's lab, the decoration of a butterfly's
wing is a much more recent invention than the building of the
wing itself: "Evolution, somewhere along the line, took this
system and came up with a way to reuse it in an entirely new
context while maintaining its original function."

"To our thinking, the reuse of genes makes innovation easier,"
said Carroll, a biologist whose work has helped resolve the
role genes play in making such things as arms, legs and wings .

"Evolution," he said, "is working by integrating sets of things
it already has. You're using a circuit over and over again."

How butterflies co-opt existing genetic programs to create
eyespot patterns that help them fool predators, said Carroll,
may in fact be a general mechanism animals use to create
"luxury items -- teeth, antlers, shells, hair, coloration -- in the
course of evolution."

"The invention of these novelties is an important facet of animal
evolution," said Lewis, a UW-Madison post-doctoral fellow.
"They impact hugely the lifestyles of the organisms."

Moreover, according to Carroll, since these luxuries are genetic-
ally wired to a specific developmental output, they can be further
tinkered with at the genetic level to create new variants.

Think, for example, of the enormous diversity of pattern and
color in butterflies, or the array of antlers sported by different
members of the deer family such as elk and moose.

"Once you make a new connection, it can independently evolve"
through the interplay of development and genetic change, Carroll
said. "Evolution can muck with that by changing things in the
circuit. At the ends of these (genetic) pathways, the output can
be very different."

"One of the amazing things about butterflies is that these genetic
programs result in a tremendous variety of color patterns, not
structures," said Lewis.

"Few would have guessed," said Keys, "that those beautiful
color patterns evolved from the same genetic processes which
all insects use to shape their wings."

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Evolution Seems To Have Speed Limits, Microbial Study Shows
Date: Posted 1/19/1999

Excerpt: Some of the world's most notorious disease-causing
organisms are ones that evolve quickly to cope with their envir-
onment. Now, a team of MSU scientists has learned about what
controls the speed of evolutionary adaptation.

... "People find it intrinsically interesting to watch evolution in
action," Lenski said. "And there is special interest in understanding
the evolution of disease-causing organisms."

... For an organism to adapt, it needs two processes: mutation
and natural selection.

Mutation is a random change in the organism's genetic structure.

Most mutants are harmful and don't survive.

Occasionally, however, a mutation brings a useful change.

Natural selection is the process that amplifies the useful mutations.

If the mutations are useful, they survive and multiply. ...

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Study Of Origin Of Species Enters The Molecular Age
Date: Posted 11/20/1998

Excerpt: Nothing brings two people closer together than sex,
but for closely related species of fruit flies, it may be what keeps
them apart.

Researchers at the University of Chicago have recently discov-
ered a gene that appears to play a crucial role in causing one
species to split into two--and stay that way.

The gene causes the male progeny of two recently separated
species to be sterile--a condition known as hybrid male sterility.

"How speciation occurs is one of the central questions in evolu-
tionary biology," says Chung-I Wu, Ph.D., chairman and pro-
fessor of the department of ecology & evolution at the Univer-
sity of Chicago, and senior author of the paper in the Novem-
ber 20 issue of Science.

"Geographic isolation and changes in the environment are only
a part of what drives speciation. There are also changes at the
genetic level that are driven by sexual selection. As a result, two
newly formed species can't mix back into one." ...

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Ancient 'Volcanic Winter' Tied To
Rapid Genetic Divergence In Humans
Date: Posted 9/8/1998

Excerpt: A new hypothesis about recent human evolution
suggests that a horrific "volcanic winter" 71,000 years ago,
followed by the coldest 1,000 years of the last Ice Age,
brought widespread famine and death to modern human
populations around the world.

The abrupt "bottleneck," or decrease, in our ancestors' popu-
lations, in turn, brought about the rapid "differentiation" - or
genetic divergence - of the surviving populations.

The hypothesis, offered by anthropologist Stanley Ambrose
of the University of Illinois, proposes that a volcanic winter
reduced populations to "levels low enough for evolutionary
changes, which occur much faster in small populations, to
produce rapid population differentiation," Ambrose said.

If, as he believes, the eruption of Mount Toba in Sumatra
caused the bottleneck, "then modern human races may have
diverged abruptly, only 70,000 years ago," Ambrose wrote
in the June issue of the Journal of Human Evolution.

... Ambrose has linked geneticists' research to that of vol-
canologists Michael Rampino, Stephen Self, Greg Zielinski
and colleagues, which shows the super-eruption of Toba
caused a volcanic winter that lasted six years and signifi-
cantly altered global climate for the next 1,000 years.

Those six years of "relentless volcanic winter" led to sub-
stantial lowering of global temperatures, drought and famine,
and to a global human population crash during which, if
geneticists are correct, no more than 15,000 to 40,000 peo-
ple survived.

"The standard view of human evolution has been that modern
populations evolved from an ancient African ancestor. We
assumed that they differentiated gradually because we assumed
ancestral populations were large and stable," Ambrose said.

But, he noted, genetic research now demonstrates that changes
in population size were sometimes dramatic. The new model
resolves the paradox of the recent African origin model: If we
are all so recently "out of Africa," why don't we all look like

"When our African recent ancestors passed through the prism
of Toba's volcanic winter, a rainbow of differences appeared,"
Ambrose said.

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Yale Scientists Recreate Molecular "Fossils," Now Extinct,
That May Have Existed At The Beginning Of Life
Date: Posted 6/10/1998

Excerpt: Yale scientists report they have synthesized mole-
cules like those that probably gave rise to the earliest life
forms on Earth nearly 4 billion years ago, thus creating a
biochemist's version of "Jurassic Park" populated by exotic
molecular "fossils" that have long since become extinct.

... The feat was accomplished using a technique known as
test-tube evolution.

Breaker's tailor-made enzyme is the first known nucleic
acid enzyme that uses an amino acid to trigger chemical
activity, and it brings scientists a step closer to finding
the precursor of all life -- a single molecule containing
both genetic code and an enzyme capable of triggering

Which Came First -- DNA, RNA Or Proteins?

The discovery provides important clues to the chicken-or-
egg dilemma of which came first -- DNA, RNA or proteins.

Most scientists agree life as we know it cannot exist without
DNA as the storehouse of genetic code, RNA as the genetic
messenger, and proteins to carry out the chemistry of repro-

Can any one of these three key molecules have existed as
the precursor of the other two, serving as both chicken and

Evidence is mounting that "it was an RNA World at the dawn
of life as the Earth began to cool," said Breaker. ..."

... "Our latest findings not only improve our understanding
about the origins of life, they also expand our skills in mol-
ecular evolution," he said.

"While we may not be able to resurrect fossilized creatures
like they did in 'Jurassic Park,' we very well may be able to
recreate many of the ancient enzymes that were needed at
the very beginning of life nearly 4 billion years ago."

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Gene Study Shows Mammals Lived
Before Extinction Of The Dinosaurs
Date: Posted 5/6/1998

Excerpt: Overwhelming evidence from the largest evolu-
tionary study of gene sequences ever performed shows
that the major groups of mammals emerged well before
the extinction of the dinosaurs.

... The evolution of mammals appears to have occurred
gradually by the isolation of breeding groups when the
continents broke apart, not suddenly by the rapid filling
of ecological niches left vacant when the dinosaurs became
extinct," Hedges says.

The massive gene study suggests that modern orders of
mammals first evolved when the continents were separating
during the Cretaceous era about 100 million years ago--much
earlier than some previous estimates based on fossil studies,
which link the evolutionary event to mass extinctions 65 mil-
lion years ago.

"This is the first time we ever have been able to estimate
when all these lifeforms appeared on Earth," Hedges says.
"Fossils can't give us this information, partly because there
are huge periods of Earth's history from which not enough
fossils have been found to make reliable estimates."

... The scientists sifted through many thousands of vertebrate
gene sequences from hundreds of species to find those that
develop mutations at a constant rate over time, which Kumar
and Hedges used like the ticking of a molecular clock to trace
the history of each species back to its origin.

The researchers found that their molecular clock yielded
origin dates similar to those based on fossil dating for many
species, but for others the genetic clues lead back to a much
earlier time. ...

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Evolution Re-Sculpted Animal Limbs By Genetic
Switches Once Thought Too Drastic For Survival
Date: Posted 8/18/1997

Excerpt: Extremely powerful genes that govern the shape of
an embryo from the earliest stages of development have been
tinkered with by nature over the course of evolution to create
the enormously wide range of animal forms ...

Homeotic, or Hox genes specify the identity of segments along
the embryo's body axis and regulate the formation of major
structures in every animal studied.

... changes in the pattern of activity of two Hox genes in crusta-
ceans are linked to the relatively sudden evolutionary develop-
ment of useful, distinctive feeding limbs called maxillipeds
(literally jaw-feet) where swimming or walking legs once were.

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O - r - i - g - i - n - s /
E - v - o - l - u - t - i - o - n (072101)
"... Links to a comprehensive view (the
standard origins links which I've been
maintaining for the last few years) and
links expanding on -and- complementing
that view are included in this post. ..."

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Creationism Evolves
Review by Eugenie C. Scott

Tower of Babel: The Evidence against the New Creationism
by Robert T. Pennock


... Intelligent-design creationists are primarily conservative
Christians greatly concerned over the increasing secularization
of U.S. society.

They wish to promote Christian theism over philosophical
materialism, the view that there are no supernatural forces in
the universe, only matter, energy and their interactions.

Because science rules out supernatural explanations, intel-
ligent-design creationists believe that it promotes philoso-
phical materialism and thus devalues faith.

They accuse scientists of clinging to their naturalistic explan-
ations because of preexisting materialist prejudice rather than
the power of empirical evidence.

Because evolution deals with theologically sensitive issues,
such as humanity's place in the universe, it becomes the
special target of intelligent-design creationists.

Movement leader Phillip E. Johnson, a professor of criminal
law at the University of California at Berkeley, argues that by
showing the weaknesses in evolution, they will drive a wedge
into the ideology of materialism, and theism will emerge tri-

One of the goals is to replace modern science with a "theistic
science" in which supernatural explanations will be allowed.

It is therefore a religious movement that is both antiscience
--at least as science is practiced today--and antievolutionary.

... Johnson and other leaders try hard to hide theological dif-
ferences in and outside their camp, claiming that such "details"
as the age of the earth, Noah's Flood and the like should be
set aside until theism triumphs over the evils of materialist

Intelligent-design creationists try to keep the peace by avoiding
any specific empirical claim about what the designer might have
done, relying instead on bashing evolution.

In this way, the movement shows its inheritance from its cre-
ation science ancestor, which specialized in the negative argu-
ment of "if evolution is wrong, then creationism is right."

... Intelligent-design creationism versus evolution is not just a
philosophical and theological intellectual exercise: it's also a
fight over what will be taught in our public schools.

... At heart it is religious (Pennock relates how, on creationist
Web sites and among believers, "intelligent designer" is des-
cribed as the "politically correct term for God") and to qualify
as scientific, it has to argue for the redefinition of science to
include "intervention"--miracles, by any other name.

... Intelligent design remains a virtually empty bandwagon.

To understand why, instructors might consult Pennock's index
for long lists of "problems with arguments" of intelligent-design
creationism, of Johnson and other leaders and of terms-of-art
like "irreducible complexity," "information" and "explanatory
filter." ...

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Since the religion of creationism (or the latest evolved version
of it, intelligent design) is present as an implied or overt aspect
of some religions, especially fundamentalist ones, the following
excerpts from a recent Scientific American article are provided
to help folks understand the way in which science, evolution,
and open-minded pursuit of verity are inconsistent with the crea-
tionist philosophies and their intelligent design offshoots ...

Scientific American - July 2002 issue
15 Answers to Creationist Nonsense

- - - begin excerpts - - -

Opponents of evolution want to make a place for creationism
by tearing down real science, but their arguments don't hold up

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Some antievolutionists, such as Philip E. Johnson, a law pro-
fessor at the University of California at Berkeley and author of
Darwin on Trial, admit that they intend for intelligent-design
theory to serve as a "wedge" for reopening science classrooms
to discussions of God.


In addition to the theory of evolution, meaning the idea of descent
with modification, one may also speak of the fact of evolution.
The NAS defines a fact as "an observation that has been repeat-
edly confirmed and for all practical purposes is accepted as 'true.'"
The fossil record and abundant other evidence testify that organ-
isms have evolved through time. Although no one observed those
transformations, the indirect evidence is clear, unambiguous and


"Survival of the fittest" is a conversational way to describe natural
selection, but a more technical description speaks of differential
rates of survival and reproduction. That is, rather than labeling
species as more or less fit, one can describe how many offspring
they are likely to leave under given circumstances.


Microevolution looks at changes within species over time--changes
that may be preludes to speciation, the origin of new species.

Macroevolution studies how taxonomic groups above the level of
species change. Its evidence draws frequently from the fossil record
and DNA comparisons to reconstruct how various organisms may
be related.

These days even most creationists acknowledge that microevolu-
tion has been upheld by tests in the laboratory (as in studies of cells,
plants and fruit flies) and in the field (as in Grant's studies of evolving
beak shapes among Galápagos finches). Natural selection and other
mechanisms--such as chromosomal changes, symbiosis and hybrid-
ization--can drive profound changes in populations over time.

The historical nature of macroevolutionary study involves inference
from fossils and DNA rather than direct observation. Yet in the his-
torical sciences (which include astronomy, geology and archaeology,
as well as evolutionary biology), hypotheses can still be tested by
checking whether they accord with physical evidence and whether
they lead to verifiable predictions about future discoveries.


No evidence suggests that evolution is losing adherents. Pick up
any issue of a peer-reviewed biological journal, and you will find
articles that support and extend evolutionary studies or that embrace
evolution as a fundamental concept. Conversely, serious scientific
publications disputing evolution are all but nonexistent.


Creationists retort that a closed-minded scientific community rejects
their evidence. Yet according to the editors of Nature, Science and
other leading journals, few antievolution manuscripts are even sub-


Evolutionary biologists passionately debate diverse topics: how
speciation happens, the rates of evolutionary change, the ancestral
relationships of birds and dinosaurs, whether Neandertals were a
species apart from modern humans, and much more.

These disputes are like those found in all other branches of science.

Acceptance of evolution as a factual occurrence and a guiding prin-
ciple is nonetheless universal in biology.

Unfortunately, dishonest creationists have shown a willingness to
take scientists' comments out of context to exaggerate and distort
the disagreements.


New species evolve by splintering off from established ones, when
populations of organisms become isolated from the main branch
of their family and acquire sufficient differences to remain forever
distinct. The parent species may survive indefinitely thereafter, or
it may become extinct.


The origin of life remains very much a mystery, but biochemists
have learned about how primitive nucleic acids, amino acids and
other building blocks of life could have formed and organized
themselves into self-replicating, self-sustaining units, laying the
foundation for cellular biochemistry.

Astrochemical analyses hint that quantities of these compounds
might have originated in space and fallen to earth in comets, a
scenario that may solve the problem of how those constituents
arose under the conditions that prevailed when our planet was

Creationists sometimes try to invalidate all of evolution by pointing
to science's current inability to explain the origin of life. But even
if life on earth turned out to have a nonevolutionary origin (for
instance, if aliens introduced the first cells billions of years ago),
evolution since then would be robustly confirmed by countless
microevolutionary and macroevolutionary studies.


Chance plays a part in evolution (for example, in the random muta-
tions that can give rise to new traits), but evolution does not depend
on chance to create organisms, proteins or other entities.

Quite the opposite: natural selection, the principal known mechanism
of evolution, harnesses nonrandom change by preserving "desirable"
(adaptive) features and eliminating "undesirable" (nonadaptive) ones.

As long as the forces of selection stay constant, natural selection can
push evolution in one direction and produce sophisticated structures
in surprisingly short times.


the Second Law [of thermodynamics] permits parts of a system to
decrease in entropy as long as other parts experience an offsetting

Thus, our planet as a whole can grow more complex because the
sun pours heat and light onto it, and the greater entropy associated
with the sun's nuclear fusion more than rebalances the scales.

Simple organisms can fuel their rise toward complexity by consuming
other forms of life and nonliving materials.


biology has catalogued many traits produced by point mutations
(changes at precise positions in an organism's DNA)--bacterial
resistance to antibiotics, for example.


molecular biology has discovered mechanisms for genetic change
that go beyond point mutations, and these expand the ways in which
new traits can appear.


Evolutionary biologists have written extensively about how natural
selection could produce new species.


Natural selection is the best studied of the evolutionary mechanisms,
but biologists are open to other possibilities as well. Biologists are
constantly assessing the potential of unusual genetic mechanisms for
causing speciation or for producing complex features in organisms.


the scientific literature does contain reports of apparent speciation
events in plants, insects and worms. In most of these experiments,
researchers subjected organisms to various types of selection--for
anatomical differences, mating behaviors, habitat preferences and
other traits--and found that they had created populations of organ-
isms that did not breed with outsiders.


paleontologists know of many detailed examples of fossils interme-
diate in form between various taxonomic groups.


evolutionists can cite further supportive evidence from molecular

All organisms share most of the same genes, but as evolution pre-
dicts, the structures of these genes and their products diverge among
species, in keeping with their evolutionary relationships.

Geneticists speak of the "molecular clock" that records the passage
of time. These molecular data also show how various organisms are
transitional within evolution.


Darwin suggested that even "incomplete" eyes might confer benefits
(such as helping creatures orient toward light) and thereby survive
for further evolutionary refinement.

Biology has vindicated Darwin: researchers have identified primitive
eyes and light-sensing organs throughout the animal kingdom and
have even tracked the evolutionary history of eyes through compar-
ative genetics. (It now appears that in various families of organisms,
eyes have evolved independently.)


It is wrong to insinuate that the field of explanations consists only
of random processes or designing intelligences.

Researchers ... have demonstrated that simple, undirected processes
can yield extraordinarily complex patterns.

Some of the complexity seen in organisms may therefore emerge
through natural phenomena that we as yet barely understand. But
that is far different from saying that the complexity could not have
arisen naturally.


Time and again, science has shown that methodological naturalism
can push back ignorance, finding increasingly detailed and informa-
tive answers to mysteries that once seemed impenetrable: the nature
of light, the causes of disease, how the brain works.

Evolution is doing the same with the riddle of how the living world
took shape. Creationism, by any name, adds nothing of intellectual
value to the effort.

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Other Resources for Defending Evolution

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The evidence for evolution is literally overwhelming. Here
are a few pertinent links from the online version of the
Encyclopedia Britannica (paid subscription required
for comprehensive access beyond a few sentences for
each link) ...

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Excerpt: "Study of living things and their vital processes.
... Biology is often approached today on the basis of
levels that deal with fundamental units of life. ..."

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Creation Myth

Excerpt: "Philosophical and theological elaboration
of the primal myth of creation within a religious com-
munity. ..."

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Excerpt: "Counterrevolutionary, fundamentalist theory
or doctrine that postulates that matter, the various
forms of life, and the world were created by God out
of nothing. ..."

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Excerpt: "The common name given to any of certain
extinct reptiles, often very large, that thrived worldwide
for some 150 million years and that died out at the end
of the Mesozoic Era, about 66.4 million years ago. ..."

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Excerpt: "Theory in biology postulating that the various
types of animals and plants have their origin in other pre-
existing types and that the distinguishable differences are
due to modifications in successive generations. ..."

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Excerpt: "Study of heredity in general and of genes in
particular. ... Genetics may be defined as the study of
the way in which genes operate and the way in which
they are transmitted from parents to offspring. ..."

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Human Evolution

Excerpt: "Evolution of modern human beings from
nonhuman and extinct hominid forms. The main
stages of hominid evolution are represented by the
australopithecines, Homo habilis, Homo erectus,
and Homo sapiens. ..."

- - -


Excerpt: "The state of a material complex or individual
characterized by the capacity to perform certain func-
tional activities, including metabolism, growth, repro-
duction, and some form of responsiveness and adapta-
tion. ... The profusion of life on Earth has been studied
in great detail, and a number of general principles have
been revealed. Foremost among them is the principle of
evolution by natural selection-the stepwise adaptation
of organisms to their environment with increasing preci-
sion by small random mutations, or changes, in their her-
editary material-which is the feature that distinguishes
living from non-living matter. ..."

- - -


Excerpt: "In biology, the study of the size, shape, and
structure of animals, plants, and microorganisms and
of the relationships of the parts comprising them. The
term refers to the general aspects of biological form
and arrangement of the parts of a plant or an animal. ..."

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(end 3 of 3)

Posts in this series:

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (1 of 3)

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (2 of 3)

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (3 of 3)

Preponderance of Evidence for Naturalistic
Origins and Evolution of Life (expanded - 4 of 4)

- - - Additional Information of Relevance - - -

Origins of Energy, Matter, Space, Time, and Life (1 of 2)

Origins of Energy, Matter, Space, Time, and Life (2 of 2)

- - -