Booklet > Creation or Evolution Two Supposed Examples = of Darwinian Evolution

Looking for proof of evolution? Biology textbooks frequently cite two = examples to show that Darwinian evolution can take place in the real = world.

The first commonly offered example involves a species of moths in=20 19th-century England. The species had two varieties, one light- and the = other=20 dark-colored. For years the lighter variety predominated, since its = coloration=20 more closely matched the bark of trees on which it rested.

However, as soot from many factories gradually darkened the tree = bark, the=20 lighter moths stood out against the now-darkened tree trunks. Birds = could see=20 the light moths better and soon devoured most. Before long the darker = moths,=20 being better camouflaged against the darker bark, became the more common = variety. "In fact this is the first direct evidence actually obtained," = says a=20 biology textbook, "to support Darwin's theory that natural selection = occurs"=20 (Contemporary Biology, 1973, p. 567). Convincing evidence-or is = it?

This actually might have been a case of Darwinian natural selection = changing=20 the species to confer a survival advantage-if the light moths had turned = into=20 dark ones. But no such thing happened. In fact, both types were already = in=20 existence. The lighter moths didn't evolve into darker moths. They were = eaten.=20 The proportion of dark moths increased while the light moths = decreased.

As a science publication admitted: "Students should understand that = this is=20 not an example of evolutionary change from light-colored to dark-colored = moths,=20 because both kinds were already in the population" (Science = Framework,=20 1990, p. 103).

So nothing new came into existence. What changed was not the moths=20 themselves, simply the proportion of the types of moths. It is ironic = that now,=20 with stricter regulation of industrial pollution, the light-moth = population has=20 made a dramatic comeback. Yet this supposed proof of evolution at work = is still=20 included in many biology textbooks.

The second commonly cited example deals with finches found in the = Gal=E1pagos=20 Islands. No less an authority than Darwin himself was the first to offer = them as=20 an example of evolution in action.

Darwin measured the beak sizes of the finches and noticed a slight = difference=20 of the birds' beaks from one island to the next. He wrote: "Seeing this=20 gradation and diversity of structure in one small, intimately related = group of=20 birds, one might really fancy that from an original paucity of birds in = this=20 archipelago, one species had been taken and modified for different ends" = (from=20 Darwin's The Voyage of the Beagle, quoted in Contemporary=20 Biology, 1973, p. 560).

This was taken as a living proof of "evolution in action," as Julian = Huxley=20 called it.

But was it? In reality, nothing new has been created in the varying = beak=20 sizes of the finches. However, the finches' beak size and shape varied = somewhat=20 according to environmental conditions and a division of the gene pool = through=20 geographic distancing.

For instance, in 1977 a major drought occurred in Daphne, one of the=20 Gal=E1pagos Islands. While many finches died, researchers noticed the = next=20 generation, offspring of the survivors, had beaks 4 to 5 percent larger. = Their=20 stronger-beaked parents had been able to open the last remaining tough = seeds=20 that remained in the island. The bigger-beaked survivors produced a = generation=20 of bigger-beaked offspring that inherited their parents' = characteristics.

Then, in 1983, torrential rains caused flooding in the same island. = Now there=20 was an abundance of smaller seeds, and over time scientists found the = beak sizes=20 of the island's finches had diminished somewhat, adjusting to their = different=20 food supply. Now birds with smaller beaks could compete for food just as = easily,=20 and more smaller-beaked finches survived to produce offspring. But is = this=20 Darwinian evolution in action or something else?

This adaptation within the species is called microevolution. It is = the same=20 phenomenon at work when the average height of men and women increased by = several=20 inches in the Western world over the course of the 1900s. Better health = and=20 nutrition played a large part in producing larger-sized people. In the = same way,=20 microevolution is at work when breeders produce varieties ranging from=20 Chihuahuas to Great Danes from the one species Canis familiaris-the = domestic=20 dog.

These examples show, as in the rest of nature, that all species do = have a=20 margin of change available within their genetic pool to adapt to = conditions.=20 This trait is found in man, who can adapt to freezing weather, as the = Eskimos=20 do, or to the broiling sun in the desert, as bedouins have done. But = bedouins=20 and Eskimos are still human beings, and if they changed environments = again=20 eventually their offspring would also go through minor changes to better = adapt=20 to their new environment.

What has never been scientifically demonstrated-in spite of many = examples of=20 wishful thinking-is macroevolution, or the change from one distinct = species to=20 another. Dogs have never evolved into birds or human beings.

Phillip Johnson goes to the heart of the matter: "Critics of = evolutionary=20 theory are well aware of the standard examples of microevolution, = including dog=20 breeding and the cyclical variations that have been seen in things like = finch=20 beaks and moth populations. The difference is that we interpret these=20 observations as examples of the capacity of dogs and finches to vary = within=20 limits, not of a process capable of creating dogs and finches, much less = the=20 main groups of plants and animals, in the first place = . . .

"As any creationist (and many evolutionists) would see the matter, = making the=20 case for 'evolution' as a general theory of life's history requires a = lot more=20 than merely citing examples of small-scale variation. It requires = showing how=20 extremely complex biological structures can be built up from simple = beginnings=20 by natural processes, without the need for input or guidance from a = supernatural=20 Creator" (Reason in the Balance, p. 74).

So these two supposed examples of evolution at work are really no = proof at=20 all of anything-much less how any of these creatures-moths, dogs, = finches or=20 humans-came to exist.

Creation or Evolution =97 Does It Really Matter What You = Believe?

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Two Supposed Examples of Darwinian Evolution

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