Darwin's Theory of Evolution - The Premise
Darwin's Theory of Evolution is
the widely held notion that all life is related and has descended from a common
ancestor: the birds and the bananas, the fishes and the flowers -- all related.
Darwin's general theory presumes the development of life from non-life and
stresses a purely naturalistic (undirected) "descent with
modification". That is, complex creatures evolve from more simplistic
ancestors naturally over time. In a nutshell, as random genetic mutations occur
within an organism's genetic code, the beneficial mutations are preserved
because they aid survival -- a process known as "natural selection."
These beneficial mutations are passed on to the next generation. Over time,
beneficial mutations accumulate and the result is an entirely different
organism (not just a variation of the original, but an entirely different
creature).
Darwin's Theory of Evolution - Natural
Selection
While Darwin's Theory of
Evolution is a relatively young archetype, the evolutionary worldview itself is
as old as antiquity. Ancient Greek philosophers such as Anaximander postulated
the development of life from non-life and the evolutionary descent of man from
animal. Charles Darwin simply brought something new to the old philosophy -- a
plausible mechanism called "natural selection." Natural selection
acts to preserve and accumulate minor advantageous genetic mutations. Suppose a
member of a species developed a functional advantage (it grew wings and learned
to fly). Its offspring would inherit that advantage and pass it on to their
offspring. The inferior (disadvantaged) members of the same species would
gradually die out, leaving only the superior (advantaged) members of the
species. Natural selection is the preservation of a functional advantage that
enables a species to compete better in the wild. Natural selection is the
naturalistic equivalent to domestic breeding. Over the centuries, human
breeders have produced dramatic changes in domestic animal populations by
selecting individuals to breed. Breeders eliminate undesirable traits gradually
over time. Similarly, natural selection eliminates inferior species gradually
over time.
Darwin's Theory of Evolution - Slowly But
Surely...
Darwin's Theory of Evolution is a
slow gradual process. Darwin wrote, "…Natural selection acts only by
taking advantage of slight successive variations; she can never take a great
and sudden leap, but must advance by short and sure, though slow steps."
Thus, Darwin conceded that, "If it could be demonstrated that any complex
organ existed, which could not possibly have been formed by numerous,
successive, slight modifications, my theory would absolutely break down."
Such a complex organ would be known as an "irreducibly complex system".
An irreducibly complex system is one composed of multiple parts, all of which
are necessary for the system to function. If even one part is missing, the
entire system will fail to function. Every individual part is integral. Thus,
such a system could not have evolved slowly, piece by piece. The common
mousetrap is an everyday non-biological example of irreducible complexity. It
is composed of five basic parts: a catch (to hold the bait), a powerful spring,
a thin rod called "the hammer," a holding bar to secure the hammer in
place, and a platform to mount the trap. If any one of these parts is missing,
the mechanism will not work. Each individual part is integral. The mousetrap is
irreducibly complex.
Darwin's Theory of Evolution - A Theory In
Crisis
Darwin's Theory of Evolution is a
theory in crisis in light of the tremendous advances we've made in molecular
biology, biochemistry and genetics over the past fifty years. We now know that
there are in fact tens of thousands of irreducibly complex systems on the
cellular level. Specified complexity pervades the microscopic biological world.
Molecular biologist Michael Denton wrote, "Although the tiniest bacterial
cells are incredibly small, weighing less than 10-12 grams, each is in effect a
veritable micro-miniaturized factory containing thousands of exquisitely
designed pieces of intricate molecular machinery, made up altogether of one
hundred thousand million atoms, far more complicated than any machinery built
by man and absolutely without parallel in the non-living world."
And we don't need a microscope to
observe irreducible complexity. The eye, the ear and the heart are all examples
of irreducible complexity, though they were not recognized as such in Darwin's
day. Nevertheless, Darwin confessed, "To suppose that the eye with all its
inimitable contrivances for adjusting the focus to different distances, for
admitting different amounts of light, and for the correction of spherical and
chromatic aberration, could have been formed by natural selection, seems, I
freely confess, absurd in the highest degree."
