Author: Mark Isaak (isaak@aurora.com) Title: Five Major Misconceptions about Evolution Upd

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Author: Mark Isaak (isaak@aurora.com)
 Title: Five Major Misconceptions about Evolution
Update: 1/3/95
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A large part of the reason why Creationist arguments against evolution can
sound so persuasive is because they don't address evolution, but rather
argue against a set of misunderstandings that people are right to consider
ludicrous.  The Creationists wrongly believe that their understanding of
evolution is what the theory of evolution really says, and declare evolution
banished.  In fact, they haven't even addressed the topic of evolution.
(The situation isn't helped by poor science education generally.  Even most
beginning college biology students don't understand the theory of
evolution.)

The five propositions below seem to be the most common misconceptions based
on the Creationist straw-man version of evolution.  If you hear anyone
making any of them, chances are excellent that they don't know enough about
the real theory of evolution to make informed opinions about it.

 - Evolution has never been observed.

 - Evolution violates the 2nd law of thermodynamics.

 - There are no transitional fossils.

 - The theory of evolution says that life originated, and evolution
   proceeds, by random chance.

 - Evolution is only a theory; it hasn't been proved.

Explanations of why these statements are wrong are given below.  They are
brief and therefore somewhat simplified; consult the references at the end
for more thorough explanations.


(-) Evolution has never been observed.

Biologists define evolution as a change in the gene pool of a population
over time.  One example is insects developing a resistance to pesticides
over the period of a few years.  Even most Creationists recognize that
evolution at this level is a fact.  What they don't appreciate is that this
rate of evolution is all that is required to produce the diversity of all
living things from a common ancestor.

The origin of new species by evolution has also been observed, both in the
laboratory and in the wild.  See, for example: 
    Dobzhansky, T. and O. Pavlovsky. 1971. Experimentally created incipient
    species of Drosophila.  Nature. 230:289-292.
The "Observed Instances of Speciation" FAQ in the talk.origins archives
gives several additional examples.

Even without these direct observations, it would be wrong to say that
evolution hasn't been observed.  Evidence isn't limited to seeing something
happen before your eyes.  Evolution makes predictions about what we would
expect to see in the fossil record, comparative anatomy, genetic sequences,
geographical distribution of species, etc., and these predictions have been
verified many times over.  The number of observations supporting evolution
is overwhelming.

What hasn't been observed is one animal abruptly changing into a radically
different one, such as a frog changing into a cow.  This is not a problem
for evolution because evolution doesn't propose occurrences even remotely
like that.  In fact, if we ever observed a frog turn into a cow, it would be
very strong evidence *against* evolution.


(-) Evolution violates the 2nd law of thermodynamics.

This shows more a misconception about thermodynamics than about evolution.
The second law of thermodynamics says, "No process is possible in which the
*sole result* is the transfer of energy from a cooler to a hotter body."
[Atkins, 1984, _The Second Law_, pg. 25]  Now you may be scratching your
head wondering what this has to do with evolution.  The confusion arises
when the 2nd law is phrased in another equivalent way, "The entropy of a
closed system cannot decrease."  Entropy is an indication of unusable energy
and often (but not always!) corresponds to intuitive notions of disorder or
randomness.  Creationists thus misinterpret the 2nd law to say that things
invariably progress from order to disorder.

However, they neglect the fact that life is not a closed system.  The sun
provides more than enough energy to drive things.  If a mature tomato plant
can have more usable energy than the seed it grew from, why should anyone
expect that the next generation of tomatoes can't have more usable energy
still?  Creationists sometimes try to get around this by claiming that the
information carried by living things lets them create order.  However, not
only is life irrelevant to the 2nd law, but order from disorder is common in
nonliving systems, too.  Snowflakes, sand dunes, tornadoes, stalactites,
graded river beds, and lightning are just a few examples of order coming
from disorder in nature; none require an intelligent program to achieve that
order.  In any nontrivial system with lots of energy flowing through it, you
are almost certain to find order arising somewhere in the system.  If order
from disorder is supposed to violate the 2nd law of thermodynamics, why is
it ubiquitous in nature?

The thermodynamics argument against evolution displays a misconception about
evolution as well as about thermodynamics, since a clear understanding of
how evolution works should reveal major flaws in the argument.  Evolution
says that organisms reproduce with only small changes between generations
(after their own kind, so to speak).  For example, animals might have
appendages which are longer or shorter, thicker or flatter, lighter or
darker than their parents.  Occasionally, a change might be on the order of
having four or six fingers instead of five.  Once the differences appear,
the theory of evolution calls for differential reproductive success.  For
example, maybe the animals with longer appendages survive to have more
offspring than short-appendaged ones.  All of these processes can be
observed today.  They obviously don't violate any physical laws.


(-) There are no transitional fossils.

A transitional fossil is one that looks like it's from organism intermediate
between two lineages, meaning it has some characteristics of lineage A, some
characteristics of lineage B, and probably some characteristics part way
between the two.  Transitional fossils can occur between groups of any
taxonomic level, such as between species, between orders, etc.  Ideally, the
transitional fossil should be found stratigraphically between the first
occurrence of the ancestral lineage and the first occurrence of the
descendent lineage, but evolution also predicts the occurrence of some
fossils with transitional morphology that occur after both lineages.
There's nothing in the theory of evolution which says an intermediate form
(or any organism, for that matter) can have only one line of descendents, or
that the intermediate form itself has to go extinct when a line of
descendents evolves.

To say there are no transitional fossils is simply false.  Paleontology has
progressed a bit since _Origin of Species_ was published, uncovering
thousands of transitional fossils, by both the temporally restrictive and
the less restrictive definitions.  The fossil record is still spotty and
always will be; erosion and the rarity of conditions favorable to
fossilization make that inevitable.  Also, transitions may occur in a small
population, in a small area, and/or in a relatively short amount of time;
when any of these conditions hold, the chances of finding the transitional
fossils goes down.  Still, there are still many instances where excellent
sequences of transitional fossils exist.  Some notable examples are the
transitions from reptile to mammal, from land animal to early whale, and
from early ape to human.  For many more examples, see faq-transitional in
the talk.origins archive, and see
http://www.geo.ucalgary.ca/~macrae/talk_origins.html for sample images for
some invertebrate groups.

The misconception about the lack of transitional fossils is perpetuated in
part by a common way of thinking about categories.  When people think about
a category like "dog" or "ant," they often subconsciously believe that there
is a well-defined boundary around the category, or that there is some
eternal ideal form (for philosophers, the Platonic idea) which defines the
category.  This kind of thinking leads people to declare that Archaeopteryx
is "100% bird," when it is clearly a mix of bird and reptile features (with
more reptile than bird features, in fact).  In truth, categories are
man-made and artificial.  Nature is not constrained to follow them, and it
doesn't.

Some Creationists claim that the hypothesis of punctuated equilibrium was
proposed (by Eldredge and Gould) to explain gaps in the fossil record.
Actually, it was proposed to explain the relative rarity of transitional
forms, not their total absence, and to explain why speciation appears to
happen relatively quickly in some cases, gradually in others, and not at all
during some periods for some species.  In no way does it deny that
transitional sequences exist.  In fact, both Gould and Eldredge are
outspoken opponents of Creationism.
    "But paleontologists have discovered several superb examples of
    intermediary forms and sequences, more than enough to convince any
    fair-minded skeptic about the reality of life's physical genealogy."
		- Stephen Jay Gould, _Natural History_, May 1994


(-) The theory of evolution says that life originated, and evolution
    proceeds, by random chance.

There is probably no other statement which is a better indication that the
arguer doesn't understand evolution.  Chance certainly plays a large part in
evolution, but this argument completely ignores the fundamental role of
natural selection, and selection is the very opposite of chance.  Chance, in
the form of mutations, provides genetic variation, which is the raw material
that natural selection has to work with.  From there, natural selection
sorts out certain variations.  Those variations which give greater
reproductive success to their possessors (and chance ensures that such
beneficial mutations will be inevitable) are retained, and less successful
variations are weeded out.  When the environment changes, or when organisms
move to a different environment, different variations are selected, leading
eventually to different species.  Harmful mutations usually die out quickly,
so they don't interfere with the process of beneficial mutations
accumulating.

Nor is abiogenesis (the origin of the first life) due purely to chance.
Atoms and molecules arrange themselves not purely randomly, but according to
their chemical properties.  In the case of carbon atoms especially, this
means complex molecules are sure to form spontaneously, and these complex
molecules can influence each other to create even more complex molecules.
Once a molecule forms that is approximately self-replicating, natural
selection will guide the formation of ever more efficient replicators.  The
first self-replicating object didn't need to be as complex as a modern cell
or even a strand of DNA.  Some self-replicating molecules are not really all
that complex (as organic molecules go).

Some people still argue that it is wildly improbable for a given
self-replicating molecule to form at a given point (although they usually
don't state the "givens," but leave them implicit in their calculations).
This is true, but there were oceans of molecules working on the problem, and
no one knows how many possible self-replicating molecules could have served
as the first one.  A calculation of the odds of abiogenesis is worthless
unless it recognizes the immense range of starting materials that the first
replicator might have formed from, the probably innumerable different forms
that the first replicator might have taken, and the fact that much of the
construction of the replicating molecule would have been non-random to start
with.

(One should also note that the theory of evolution doesn't depend on how the
first life began.  The truth or falsity of any theory of abiogenesis
wouldn't affect evolution in the least.)


(-) Evolution is only a theory; it hasn't been proved.

First, we should clarify what "evolution" means.  Like so many other words,
it has more than one meaning.  Its strict biological definition is "a change
in allele frequencies over time."  By that definition, evolution is an
indisputable fact.  Creationists seem to associate the word "evolution"
mainly with common descent, the theory that all life arose from one common
ancestor.  Many people believe that there is enough evidence to call this a
fact, too.  However, common descent is still not the theory of evolution,
but just a fraction of it (and a part of several quite different theories as
well).  The *theory* of evolution not only says that life evolved, it also
includes mechanisms, like mutations, natural selection, and genetic drift,
which go a long way towards explaining *how* life evolved.

Calling the theory of evolution "only a theory" is, strictly speaking, true,
but the idea it tries to convey is completely wrong.  The argument rests on
a confusion between what "theory" means in informal usage and in a
scientific context.  A theory, in the scientific sense, is "a coherent group
of general propositions used as principles of explanation for a class of
phenomena" [Random House American College Dictionary].  The term does not
imply tentativeness or lack of certainty.  Generally speaking, scientific
theories differ from scientific laws only in that laws can be expressed more
tersely.  Being a theory implies self-consistency, agreement with
observations, and usefulness.  (Creationism fails to be a theory mainly
because of the last point; it makes few or no specific claims about what we
would expect to find, so it can't be used for anything.  When it does make
falsifiable predictions, they prove to be false.)

Lack of proof isn't a weakness, either.  On the contrary, claiming
infallibility for one's conclusions is a sign of hubris.  Nothing in the
real world has ever been rigorously proved, or ever will be.  Proof, in the
mathematical sense, is possible only if you have the luxury of defining the
universe you're operating in.  In the real world, we must deal with levels
of certainty based on observed evidence.  The more and better evidence we
have for something, the more certainty we assign to it; when there is enough
evidence, we label the something a fact, even though it still isn't 100%
certain.

What evolution has is what any good scientific claim has--evidence, and lots
of it.  Evolution is supported by a wide range of observations throughout
the fields of genetics, anatomy, ecology, animal behavior, paleontology, and
others.  If you wish to challenge the theory of evolution, you must address
that evidence.  You must show that the evidence is either wrong or
irrelevant or that it fits another theory better.  Of course, to do this,
you must know both the theory and the evidence.


(-) Conclusion.

These are not the only misconceptions about evolution by any means.  Other
common misunderstandings include how geological dating techniques work,
implications to morality and religion, the meaning of "uniformitarianism,"
and many more.  To address all these objections here would be impossible.

But consider: About a hundred years ago, scientists, who were then mostly
creationists, looked at the world to figure out how God did things.  These
creationists came to the conclusions of an old earth and species originating
by evolution.  Since then, thousands of scientists have been studying
evolution with increasingly more sophisticated tools.  Many of these
scientists have excellent understandings of the laws of thermodynamics, how
fossil finds are interpreted, etc., and finding a better alternative to
evolution would win them fame and fortune.  Sometimes their work has changed
our understanding of significant details of how evolution operates, but the
theory of evolution still has essentially unanimous agreement from the
people who work on it.


(-) Further reading.

The "FAQ" files listed below are available on World Wide Web via
http://rumba.ics.uci.edu:8080/.  They are also available via ftp at
ics.uci.edu, directory /pub/origins.  Messages with more information on 
how to access them are posted regularly to talk.origins.  The archive 
also contains many other files which may be of interest.

For what evolution means, how it works, and the evidence for it:
  Colby, Chris.  faq-intro-to-biology: Introduction to Evolutionary Biology
  Mayr, Ernst.  1991.  One Long Argument
  Darwin, Charles.  1859.  On the Origin of Species by Means of Natural
    Selection

For issues and evidence of speciation:
  Boxhorn, Joseph.  faq-speciation: Observed Instances of Speciation
  Weiner, Jonathan.  1994.  The Beak of the Finch: A Story of Evolution in
    Our Time

For explanations of how randomness can lead to design:
  Dawkins, Richard.  1986.  The Blind Watchmaker
  Bonner, John T.  1988.  The Evolution of Complexity by Means of Natural
    Selection
  Kauffman, Stuart A.  1993.  The Origins of Order: Self-Organization and
    Selection in Evolution [very technical]

For a readable introduction to the 2nd law of thermodynamics:
  Atkins, Peter W.  1984.  The Second Law

For transitional fossils and the fossil record:
  Colbert, Edwin H.  1991.  Evolution of the Vertebrates, 4th ed.
  Hunt, Kathleen.  faq-transitional: Transitional Fossils

For a fairly comprehensive response to many Creationist claims:
  Strahler, Arthur.  1987.  Science and Earth History
  Meritt, Jim.  faq-meritt: Jim Meritt's general anti-creationism FAQ