Creation Facts of Life (11 page)

If natural selection is such a profound idea, and Blyth published it before Darwin, then why isn't Blyth's name a household word? Perhaps because Blyth made no more of natural selection than could be scientifically observed. It was not the
scientific
applications of natural selection that attracted attention in 1859; it was its presumed
philosophic
and
religious
implications.

Evolutionists were not content to treat natural selection as simply an observable ecological process. Darwin himself was a cautious scientist, painstaking in his work, but others, especially T.H. Huxley and Herbert Spencer, insisted on making natural selection the touchstone of a new religion, a "religion without revelation," as Julian Huxley later called it. For them, as for many others, the real significance of the Darwinian revolution was
religious
and
philosophic,
not scientific, a reason to place human opinion above God's Word. These early evolutionists were basically anti-creationists who wanted to explain design without a Designer.

In spite of what might be claimed, natural selection has been observed to produce only variation within kind: merely shifts in populations, for example, to moths with greater percentages of darker moths, to flies resistant to DDT, or to bacteria resistant to antibiotics. Modern evolutionists believe, however, that such small changes
plus vast amounts of time
could lead to huge changes, "macroevolution," change from one kind to another:
Fish to Philosopher
, as the title of Homer Smith's book puts it, or
Molecules to Man
, the subtitle of the government-funded BSCS "blue version" high school biology textbook.

Macroevolution
is the kind of change through time pictured as millions of years of struggle and death producing a "
tree of life
" rooted in chance chemical combinations forming life, and life branching out through a few simple forms to the twigs representing all the complex and varied species we have today, including man.

Beliefs about macroevolution certainly go far beyond our scientific observations of natural selection. Still, I must admit that there is a potential connection between
observed
natural selection within kind and
hypothetical
evolution from one kind to another. That connection is called "extrapolation," following a trend to its logical conclusion. Scientists extrapolate from population records, for example, to predict changes in the world population. If world population growth continued at the rate observed in the 1960s, statisticians said, then the world population by A.D. 2000 would be over six billion (as observed). Similarly, if natural selection continues over very long periods of time, evolutionists say, the same process that changes moths from mostly light to mostly dark forms will gradually change fish to philosophers or molecules to man.

Now there's nothing wrong with extrapolation in principle, but there are things to watch for in practice. For example, simple extrapolation would suggest a population of a "zillion" by A.D. 3000. Of course, there will come a point when the earth is simply not big enough to support any more people. In other words, there are
limits,
or
boundary conditions,
to logical extrapolation.

Consider my jogging (or should I say "slogging") times. Starting years ago at an embarrassing 12 minutes per mile, I knocked a minute off each week: a mile in 11 minutes, then 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. Wait a minute! As you well know, I reached my limit long before the one-minute mile! (Just where, I'll keep secret!) This is an embarrassing example, but it makes an important point: no scientist would consider extrapolation without also considering the logical limits or boundary conditions of that extrapolation.

Evolutionists are aware of the problem. They distinguish between
SUBspeciation
and
TRANSspeciation.
"Sub" is essentially variation within species, and "trans" is change from one species to another. Darwinian evolutionists believe that one can "extrapolate" from variation
within
species to evolution
between
species. But other evolutionists believe that such extrapolation goes beyond all logical limits, like my running a one-minute mile.
³⁹

What does the evidence suggest? Can evolution from "molecules to man" be extrapolated from natural selection among dark and light moths? Or are there boundary conditions and logical limits to the amount of change that can be produced by Darwin's war of nature — time, chance, struggle, and death?

The answer seems to be:
"Natural selection, yes; evolution,
no
." As it turns out, there are several factors that sharply limit the amount of change that can be produced by time, chance, and Darwinian natural selection.
⁴⁰

Darwin published his theory in 1859, before Abraham Lincoln became president, long before DNA's significance was discovered, and even before the germ theory of disease and the modern sciences of genetics and ecology were founded. It is perhaps not surprising, then, that over the past century and a half scientists have discovered a long list of factors that set definite
limits to the kind and amount of change natural selection can produce
—
no matter what the time involved
. You could calculate how long it would take you, pedaling a bicycle at 10 mph (16 kph), to reach the moon, but such an extrapolation would ignore serious limits to getting to the moon on a bicycle — even if you had zillions of years to do it!

Following are some of the limits that prevent extrapolation from natural selection to evolution — limits causing a growing number of 21st century scientists to say,
"Natural selection, yes; evolution, no."

Natural Selection, Yes; Evolution, No

(1) What does "fittest" mean?

The definition of "fittest" guarantees that
natural selection must be accepted as a fact
. Most people assume that "fitness" refers to features of structure, function, or behavior that suit an organism for a particular role in its environment. It doesn't. Fitness is defined by scientists solely in relation to relative reproductive success.
Members of a population that leave the most offspring to the next generation are fittest by definition
.

You may have thought the dark-colored peppered moth was fittest to survive in a polluted forest because it was most camouflaged. But what if the extra melanin production interfered with, say, sex hormone production and made the dark-colored moths sterile? Obviously, the superior camouflage would
not
make such a moth fittest to survive! Evolutionists think the camouflage helped, of course, but the dark moths were really determined to be "fittest to survive" because a greater percentage of their offspring survived in polluted forests than the percentage for any other color form.

Think about zebras. Their survival depends on their ability to outrun lions. So, the fastest zebra would be fittest, right? Not necessarily. Suppose the fastest zebra was hard of hearing or had a poor sense of smell. It could have outrun the lion and the rest of the herd — if only it had sensed the lion's coming! Or suppose the fastest zebra had bones that broke easily, poor digestion, and/or caught diseases easily. What looks fit to us superficially may not turn out to be fittest in nature.

So, the only way to determine fitness is to make notes on organisms in the first generation,
wait for the struggle for survival to take place
, then see which organisms actually left the most offspring to the next generation. To see how scientists calculate fitness, let's work through Figure 12, a simple example involving one pair of genes, A and a, which produce three varieties of organisms: AA, Aa, and aa. These gene combinations (genotypes) could be used to represent a variety of traits (phenotypes), e.g., tall-medium-short, fast-medium-slow, red-pink-white, smart-average-dull, heavy-medium-light, etc.

We'll start the first generation with 100 individuals: 50 AA, 30 Aa, 20 aa. The second generation coming through the struggle for survival includes 20 AA, 60 Aa, and 20 aa. All other things being equal, it's already obvious that organisms with genotype Aa were fittest, winning the struggle for survival, since they're the only group that increased in numbers. The
numerical fitness
of each group can be easily calculated. First, divide the number in the second generation in each category by the number in the first; that gives 20/50 = 0.4 for AA; 60/30 = 2.0 for Aa; and 20/20 = 1.00 for aa.

Note the highest survival ratio is the 2.0 for the Aa fittest, or winners, in this example. Calculate the
standardized fitness
value by dividing each "survival ratio" by the highest (2.0 for Aa here). This last step always gives the
winner
a fitness value of
1.00
and ranks other groups from 0 (a loser with no survivors) to some fraction of 1.00. The aa fitness here is 1.0/2.0=0.5, meaning the aa's survived about "half as well" as the fittest Aa's. The AA's did worst at surviving, about "20 percent as well" as the fittest (20/50 = 0.4 and 0.4/2.0 = 0.2).

Several profound and often misunderstood consequences follow from the simple calculation of fitness:

(a) "
Survival of the survivors
." The definition of fitness is grounded ultimately in reproductive success, so it is sometimes called
differential reproduction
or
net relative reproductive efficiency.
In far less than pompous-sounding phrases, what that boils down to is
survival of the survivors
.
Now you can see why natural selection, or survival of the fittest, is a fact
. How is it determined which organisms will be "naturally selected" as fittest? Wait for the struggle for survival to play out from one generation to the next, then count who survived in greatest numbers! An organism may be ugly, slow, or stupid, but if its offspring survive in greatest numbers, it's the fittest! (That may comfort some of us, as well as the opossum!)

Notice that natural selection is
NOT
some awesomely powerful scientific theory that enables scientists to predict future changes in populations. "
Natural selection
"
is really just a high-sounding, misinforming term
applied to the
observation
that some organisms in a varied population survive in greater numbers than others do —
survival of the survivors
.
After
scientists
observe
which organisms are "fittest" (i.e., survived in greatest relative numbers), then they can begin to
speculate on why
. Was it camouflage, speed, intelligence, fecundity (having lots of offspring easily), disease resistance, some combination or none of these, or just "blind luck"? Ecclesiastes 9:11 says, "The race is not to the swift, nor the battle to the strong [in our fallen world] …but time and chance happeneth to them all" (ASV).

Natural selection is a fact because it's a
tautology
or
truism,
a form of
circular reasoning. It is argued that the fittest are those that survive in greatest relative numbers and those that survive in the greatest relative numbers are defined as the fittest
. That's definitely
true
, but it's really just an observation, not a profound theory, and begs the question of what makes some organisms fitter than others.

The story is told of a student walking to school who saw in the grass a mouse that remained absolutely motionless as a hawk soared overhead. When she asked her teacher why, the teacher explained that mice which ran were seen and killed by the hawk, so natural selection produced those which remained motionless. The next day, the student saw a mouse running to its burrow as a hawk soared overhead. When she asked her teacher why, the teacher explained how mice that remained motionless were easy targets for the sharp-eyed hawk that killed and ate them, so natural selection favored survival of the mice which ran. The "nice" thing about "survival of the survivors" is that it can explain anything: why mice run or stay put, why some species (e.g., horseshoe crabs) never changed in "600 million years" while others changed rapidly and quickly (e.g., an insect-eater thought to have evolved into horses, whales, and bats in less than "5 million years"). The so-called "proof" that natural selection produced evolution is too often merely the argument that survivors survived!

(b)
Natural selection versus ecological competition
. Most people just assume "natural selection" for the "fittest" means the selected variety must be increasing. Actually, natural selection has nothing to do with whether a species as a whole is increasing or decreasing in numbers or staying the same (static or stable). Look back at the calculation of fitness in Figure 12. In case A, the population was static or stable; the second generation had 100 individuals like the first one did. Now imagine the population doubled to 200, and the second generation contained 40 AA, 120 Aa, and 40 aa. What would the new fitness values be? The winner ("fittest") being "naturally selected" is still Aa, and its reproductive efficiency is 120/30 = 4.0, which is the highest value. That means the standardized fitness of Aa, 4.0/4.0, is 1.00, the maximum value, just as it was in the static population. The fitness values for the other two groups are also exactly the same in the expanding population as they were for the static case. The reproductive efficiency for aa is 40/20 = 2.0, so its standardized fitness is 2.0/4.0 (the "winning" efficiency) = 0.5, "one-half" the maximum, as before. The numbers for AA are 40/50 = 0.8, and 0.8/4.0 = 0.2, exactly 20 percent of maximum as in the static population.