Darwin
concluded that color differences between sexes in birds... result
largely from female preference for bright colors in males. This
general rule has received much support since Darwin's time, but other
influences have also been noted. For example, females of species that
are exposed to predators while incubating tend to have dull colors.
Sometimes
I'm fascinated with how evolutionists' minds work. Secular
scientists claim they go wherever the evidence leads. In practice,
though, they only go where evolution can lead them. As we study
birds, for example, they don't ask, “Why are some birds brightly
plumed?” Instead they ask, “Why did bright plumage evolve?”
Evolution is the paradigm through which they interpret the evidence.
Therefore, their conclusions will always seem to support evolution.
It's a vicious, circular argument.
Let's
consider the quote from Scientific American. Their point is that
bright feathers in male birds evolved because female birds are
attracted to the bright feathers (known as sexual selection).
At the same time, female birds have drab plumage because, during
nesting, bright feathers would make them more visible to predators.
In both cases, there seems to be an obvious survival benefit in
having bright or drab feathers. The evidence, therefore, could be
said to support evolution. This is a standard argument which I've
heard made many times before. Such simple attempts to describe the
origin of bright plumage sound plausible at first. However, I don't
believe they can stand up to scrutiny. I see in them a host of
unanswered questions.
First,
explanations like this still don't answer why bright feathers
evolved. I know what they're trying to say: that the male birds with
the brightest feathers are the most successful in attracting mates so
the brightest plumage is selected more often over the drab. But
evolution is not a directed process. The desire for bright
plumage does not cause bright plumage. That would be sort of
like saying that dinosaurs evolved into birds because they wanted to
fly. For females to select bright feathers in a mate, bright
feathers must already be present in the population. If there is not
bright plumage, sexual selection will not create them no matter how
hot the hens think colorful feathers are!
This
tactic of using the survival benefit of a feature as the explanation
of why the feature evolved is prevalent in evolutionary philosophy.
I wrote
about this a while back after reading an evo-article that said
crying evolved as a way for humans to garner sympathy from each
other. No it didn't. Still, I hear stories like this all the time:
lions evolved heavy manes to protect themselves while fighting.
Giraffes evolved long necks so that they could reach the leaves at
the tops of trees. Poisonous frogs evolved bright colors to warn
away predators. The list goes on and on. It's about as ridiculous
as believing that Michael Jordan grew tall in order to play
basketball. Merely pointing out the survival benefit of a trait is
not a sufficient explanation of how or why the trait evolved.
Another
funny thing about these types of explanations is that they are so
flexible that they can describe anything. Male birds evolved bright
feathers to make themselves more attractive to females while females
of the same species evolved drab feathers in order to make them less
noticeable to predators. Wow! Members of the same species evolved
completely opposite traits in exactly the same environments for
completely different reasons.
I've
also heard that humans evolved altruism because there is a survival
benefit in a peaceful, cooperative community. Except, of course,
when we express aggressive behaviors like fighting, raping, and
killing each other. In that case, years of field research has taught
us that we're acting the same way as our cousins, the chimpanzees.
One story... er, I mean, “study,” says that we're monogamous
because that insures the greatest chance of rearing our progeny to
maturity; but another story says we're habitually unfaithful because
our evolutionary success hinges upon leaving the greatest number of
offspring.
I'm
reminded too how often we hear that similar structures in different
species are the result of shared ancestry – except when they're the
result of convergent evolution. How predictive can any scientific
theory be if it can be used to explain anything – even
completely opposite results in the evolution of members of the same
species?
Yet
perhaps the funniest thing about the Scientific American's
explanation is the seeming circular nature of it. Think about it:
make birds evolved bright feathers because female birds are attracted
to bright feathers. It's a tautology. The next question should be
obvious: why are female birds attracted to bright feathers? If
evolution were true, the preference for bright feathers is also an
evolved trait. The evolution of bright feathers isn't necessary
unless a preference for bright feathers had already evolved. Yet how
could a preference for bright feathers evolve before there were
bright feathers? What a pickle! And by the way, what survival
benefit is there to the species for the female of a species to be
attracted to the males who are the most visible to predators? That
part of the equation isn't as neatly explained.
It's
sad, really, that scientists waste their time inventing these “just
so” stories that have no value as scientific theories and, frankly,
don't even explain anything. They then foist these half-baked ideas
upon the unsuspecting public and have the nerve to be appalled that
lay people just don't understand evolution. Is this the kind of
evolution Bill Nye believes kids need to learn in order to be good
scientists?
“Good
morning, class. Today we're going to talk about bird evolution.
Please turn off your critical thinking skills and don't ask any
questions.”