Creation Facts of Life (13 page)
Lewontin recognizes that this simple (but crucial) point is often overlooked, so he gives an example. As a region becomes drier, he says, plants can respond by developing a deeper root system or a thicker cuticle (waxy coating) on the leaves, but "
only if
their gene pool contains genetic variation for root length or cuticle thickness" (emphasis added). Here again, the genes for deep roots and thick, waxy coats must be present among the genes of a kind
before
natural selection can select them. If the genes are already there, we are talking only about variation within kind, i.e., creation, not evolution. As creationists were saying
even before
Darwin's time, natural selection does
not
explain the
origin
of species or traits, but only their
preservation —
how and where certain varieties survive as they multiply and fill the earth.
Lewontin is an evolutionist and outspoken anti-creationist, but he honestly recognizes the same limitations to natural selection that creation scientists do:
…natural selection operates essentially to enable the organisms to
maintain
their state of adaptation rather than to improve it (emphasis added).
Natural selection does not lead to continual improvement (evolution); it only helps to maintain features that organisms already have (creation). Lewontin also notes that extinct species seem to have been just as fit to survive as modern ones, so he adds:
…natural selection over the long run does
not
seem to improve a species' chances of survival, but simply enables it to "track," or
keep up with,
the constantly changing environment (emphasis added).
Natural selection works only because each kind was created with adaptations (design features) and sufficient variety to multiply and fill the earth in all its ecologic and geographic variety. Without realizing it at the time, Darwin actually discovered important evidence pointing both to God's
creation
(adaptation and variation) and to the
corruption
of creation (struggle and death).
The seven points above are all
logical limits
to
extrapolating
the
hypothetical
process of evolution (macroevolution) from the
observable
process of natural selection. It really looks like using natural selection to "reach" evolution is like using a bicycle to reach the moon; the barriers are insurmountable, no matter how much time you take. Evolutionists face two even more serious difficulties in trying to explain evolution as a result of natural selection: "compound traits" and the "origin" of new traits.
(2) Compound traits or "irreducible complexity"
Many believe any genius Darwin had is found in explaining how all the complex and varied structures and functions of living things could be produced
one step at a time
by the process of natural selection. Imagine you are standing at the bottom of the Empire State Building. Getting to the top looks impossible, especially if you have to do it in one huge jump. Then someone shows you the stairway. What looked like an impossibility now seems like a certainty. The climb may be long and hard, but you could make it from the bottom to the top if you took
one step at a time
. That's the way most people now look at the world of living things. Producing life without the outside help of a Creator once seemed
impossible
. Now, say the evolutionists, the production of all life forms from simple beginnings is a virtual
certainty
—
IF AND ONLY IF
each feature is produced slowly and gradually,
one step at a time.
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Figure 13. |
Darwin himself, however, recognized that adaptations in living systems often depend on many parts working together simultaneously, and Darwin called such features "difficulties with the theory." Such
compound traits
, or systems of
irreducible complexity,
are considered the most powerful argument
against
Darwinism and have fostered the burgeoning growth of the
"Intelligent Design" (ID)
movement among secular scientists today.
46
Remember,
natural selection can be used to turn the impossible into the highly probable
IF AND ONLY IF each step
in the development of an adaptation has survival value, allowing it to increase in numbers relative to its competitors.
Throwing dynamite into the fire started by Michael Denton (
Evolution: A Theory in Crisis,
1985)
47
and Phillip Johnson
(Darwin on Trial
, 1991),
48
biochemist Michael Behe brought popularity to the Intelligent Design (ID) movement among secular scientists with the publication of his book (
Darwin's Black Box
, 1996),
49
describing stunning examples of
irreducible complexity
found in the "molecular machinery" of living cells: the astonishing rotary motor of the bacterial flagellum, photoreceptor/effector systems ("eyes"), complex stimulation/inhibition interactions in blood clotting and the immune system, etc.!!! Right now, let's look at examples of compound traits on a larger scale.
Perhaps the biggest problem for evolutionists is "the marvelous fit of organisms to their environment." As I mentioned in the first chapter, many adaptations involve whole groups of traits working together, and none of the individual pieces has any survival value ("Darwinian fitness") until the whole set is functioning together. Remember the woodpecker? Let's look at another example.
Since death entered the world, there are many large, predatory fish that roam the oceans. As they feed on smaller fish and shrimp, their mouths begin to accumulate food debris and parasites. Lacking recourse to a toothbrush, how is such a fish going to clean its teeth?
For several kinds of fish, the answer is a visit to the local cleaning station. These are special areas usually marked by the presence of certain shrimp and small, brightly colored fish, such as wrasses and gobis. Often fresh from chasing and eating other small fish and shrimp, a predatory fish may swim over to take its place in line (literally!) at the nearest cleaning station. When its turn comes, it opens its mouth wide, baring the vicious-looking teeth.
You might suspect, of course, that such a sight would frighten off the little cleaner fish and shrimp. No, into the jaws of death swim the little cleaners. Now even a friendly dog will sometimes snap at you if you try to pick off a tick, and it probably irritates the big fish to have a shrimp crawling around on its tongue and little fish picking parasites off the soft tissues of the mouth. (Try to imagine shrimp crawling around on
your
tongue!) But the big fish just hovers there, allowing the cleaners to do their work. It even holds its gill chambers open so that the shrimp can crawl around on the gill filaments, picking off parasites!
At the end of all this cleaning, the second "miracle" occurs. You might think the fish would respond, "Ah, clean teeth; SNAP, free meal!" But, no. When the cleaning is done, the big fish lets the little cleaner fish and shrimp back out. Then the big fish swims off — and begins hunting again for little fish and shrimp to eat!
The fantastic relationship just described is called
cleaning symbiosis.
Perhaps you have seen cleaner fish in a major public aquarium, or seen pictures of their behavior in television footage or nature magazines. Cleaning symbiosis is a well-known example of mutualism, an intimate relationship of benefit to both types of species involved, in this case, the "cleaner and the cleanee."
Obviously, cleaning symbiosis has survival value for both types of species involved, but does survival value explain the
origin
of this special relationship? Of course not. It makes sense to talk about survival value only
after
a trait or relationship is already in existence. Question: Did the survival value of this cleaning relationship result from time, chance, and struggle,
or
from plan, purpose, and special acts of creation?
The major problem is using Darwinian fitness to explain traits with many interdependent parts when none of the separate parts has
any
survival value. There's certainly no survival value in a small fish swimming into a large fish's mouth on the hope that the big fish has somehow evolved the desire to let it back out! Sea creatures don't provide the only examples of cleaning symbiosis, either. A bird, the Egyptian plover, can walk right into the open mouth of a Nile crocodile — and walk back out again, after cleaning the croc's mouth! On an evolutionary basis, each cleaning relationship would have to be explained separately on the basis of time, chance, struggle, and death, operating on variants of each species involved. Remember, natural selection can help explain the origin of compound traits one step at a time
IF AND ONLY IF
each separate step has survival value on its own.
The situation is even more dangerous for the famous "bombardier beetle." The bombardier is an ordinary-looking beetle, but it has an ingenious chemical defense mechanism. Imagine: Here comes a mean ol' beetle-eater, a toad, creeping up behind the seemingly unsuspecting beetle. Just as he gets ready to flash out that long, sticky tongue, the beetle swings its cannon around, and "boom!" It blasts the toad in the face with hot noxious gases at the boiling point of water, and coats the toad's tongue with a foul-tasting residue. Now that doesn't actually kill the toad, but it surely kills its taste for beetles! Pictures show the toad dragging its tongue across the sand trying to get rid of the foul taste.
Successful firing of the bombardier beetle's cannon requires two chemicals (hydrogen peroxide and hydroquinones), enzymes, pressure tanks, and a whole series of nerve and muscle attachments for aim and control. Try to imagine all those parts accumulating by time, chance, and natural selection. One crucial mistake, of course, and "boom!" the would-be bombardier beetle blows
itself
up
,
and there's surely no evolutionary future in that! Trial and error can lead to improvement only if you survive the error!
Creationists and evolutionists agree that adaptations such as the woodpecker's skull, cleaning symbiosis, and the bombardier beetle's cannon all have survival value. The question is, how did they get that way: by time, chance, struggle, and death, or by plan, purpose, and special acts of creation? When it comes to adaptations that require several traits all depending on one another, the more logical inference from the evidence seems to be creation.
(3) Origin of Traits
Darwin's theory also points us back to creative acts when it comes to the origin of traits. In spite of the title of his book,
Origin of Species,
the one thing Darwin never really dealt with was the
origin
of species. That is, he never explained the origin of the truly new traits needed to produce a truly new kind of organism, something
more
than just a variation of some existing kind. There are many other logical limits to extrapolation from natural selection to evolution, but the simplest is this: natural selection cannot explain the
origin
of traits.
Take the famous example of "Darwin's finches" (Figure 14). On the Galapagos Islands, Darwin observed a variety of finches, some with small beaks for catching insects, others with large beaks for crushing seeds, and one with the ability to use spines to pry insects from their tunnels. How did Darwin explain the "origin" of these various finches? Exactly the same way a creationist would. He saw finches with variation in beak type on the South American mainland and presumed these finches might have reached the islands on a vegetation mat or something similar. The ones with seed-crushing beaks survived where seeds were the major food source, and those with insect-catching beaks out-reproduced others where insects were the major source of food. Given finches with a variety of beak types, then, natural selection helps us to explain
how
and
where
different varieties
survived
as they multiplied and filled the earth. That, of course, is just what a creationist would say — except that a biblical creationist would add that the "struggle and death" part of migration did not begin until man's rebellion ruined the world God had created without death. (Contrast Genesis 1–2 with the Fall in Genesis 3.)
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Figure 14. |