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| Our Evolutionary Inheritance |
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When creationists say that there are no transitional fossils to support the theory of evolution, they are implicitly assuming a kind of evolution that always takes place little by little. This view of evolution is inherited from Darwin, who did conceive of evolution as a process
that occurs gradually.
But since Gould and Eldredge posited their theory
of punctuated equilibria, we know that evolution
can occur in other ways. Indeed, some species can evolve very
rapidly over periods that are brief in geological terms, followed
by long periods of stagnation. Considering the rarity of the
conditions necessary for fossilization, we can understand
why there will necessarily be some “"gaps"
in the fossil record. That in no way invalidates evolution
as we understand it today, especially after the important
contribution made by Gould and Eldredge.
Their theory of punctuated equilibria does not constitute
a complete paradigm shift, but it does let scientists revisit
Darwin's initial intuitions about the process of evolution,
intuitions that some thinkers were too quick to freeze into
dogma.
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| CREATIONIST ATTACKS ON EVOLUTION |
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For the past two decades, the
United States has been subjected to the growing influence of “"creationists" who
believe that the story of creation as told in the Bible must be taken
literally... in other words, that the universe was created in six
days, scarcely 6 000 years ago.
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Aside from the fact that
the fundamentals of creationism are contradicted by all the
currently available scientific data, many of the criticisms
that creationists commonly direct against the theory of evolution
reflect a misunderstanding of what evolution actually is.
Here are some of the most common
creationist criticisms of evolution, along with the counter-arguments
based on an accurate understanding of this subject. |
“Evolution
has never been observed.”
Evolution is basically defined as a change in the gene pool of a species over
time. There are myriad examples of this phenomenon, such as bacteria that develop
resistance to drugs or insects that develop resistance to pesticides over a short
period of time. The emergence of new species has also been observed both in the
laboratory and in nature, especially among fruit flies. And even if we did not
have these direct observations, the theory of evolution has enabled us to make
predictions regarding the fossils of species that have now disappeared, and in
terms of both comparative anatomy and geographic distribution, these predictions
have proven accurate in a multitude of cases.

“Evolution violates the second
law of thermodynamics.”
This law states that the entropy (or “"disorder")
in a closed system can only increase. Creationists simplify this
law by stating that order (and hence life) cannot have emerged
from the disorder of the inanimate things found on Earth. But creationists
thereby ignore one major fact: the Earth is not a closed system.
It constantly receives energy from the Sun and sends energy back
out into the universe in such forms as infra-red radiation. In
an open system like this, order (or “"negentropy")
can be created locally provided that energy is degraded on a larger
scale, which is the case for the organisms living on Earth. In
any case, the tendency for matter to organize itself is observed
even in inanimate things: snow flakes, sand dunes, tornadoes, and
lightning bolts are several good examples.
There are gaps (missing links)
in the fossil record.”
First of all, there are
some impressive sequences of fossils that demonstrate the
most minute steps in the transitions from reptiles to mammals
and from ancient primates to ancient humans, for example.
The presence of gaps in no way discredits the theory of evolution.
Such gaps have many possible causes, such as erosion of fossil-bearing
formations, the rareness of conditions conducive to fossilization,
and the fact that speciation can occur in a small population
or a limited area, or very rapidly (see sidebar).
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“The theory of evolution
is based on the idea that life emerged solely by chance.”
Chance, in the form of the random mutations that are the source of genetic diversity,
does indeed play an essential role in evolution. But to say that evolution is
based solely on chance is to badly misunderstand the equally fundamental role
played by natural selection. It is only by favouring some genetic variants over
others that organisms better adapted to their environment can evolve.
The final argument that creationists
marshal to try to undermine the theory of evolution is what they
call “"intelligent
design". It is based on a more subtle line of reasoning:
that the living world is so complex that only an intelligence outside
our universe could have planned it down to the last detail. But
here again, a
proper understanding of the theory of evolution would seem to obviate
the need to posit an intelligent design or a “"higher
consciousness".
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