The Mirage of "Evolution Before Our Eyes"
Darwinists taunt us with the purported knockdown observation that, "Well, how can you not believe in evolution" -- translation: the power of unguided evolution by natural selection to drive speciation -- "when we see evolution going on before our very eyes?" They don't actually mean the origination of new species, of course. But rather, minor changes of a more decorative kind that become fixed.
The problem with this argumentative gambit is that, so a new study in the Proceedings of the National Academy of Sciences shows, the decorative touches tend not to stick ("The million-year wait for macroevolutionary bursts," August 23). It's as if you were to move some furniture around in your house and then come back a while later and find it has gone back to the way it was before.
In his current book, The Greatest Show on Earth: The Evidence for Evolution, Richard Dawkins has a relevant chapter: "Before Our Very Eyes." He gives some superficially compelling examples of "evolution before our eyes": Elephant tusk size measured by the Uganda Game Department between 1925 and 1958; change in head size and diet of a Mediterranean lizard, Podarcis sicula, between 1971 and 2008 as registered by a Belgian team studying the lizard population on a pair of little islands off the Croatian coast; changes in coloring and reproductive habits among Trinidadian guppies, when transplanted from one stream containing effective predators to a tributary with less effective predators, sampled at intervals of 23 months and then 9 years; and so on.
Of course these are small-scale changes, and do not demonstrate that Darwinian evolution can produce large-scale change. But what Dawkins wants you to think is this: If stuff like this were to accumulate, then -- just imagine!
Sadly, the implication that such things give "evidence for evolution" in any meaningful sense needs to be abandoned. That's the important implication of the massive study by Oregon State University zoologist Josef C. Uyeda and his colleagues. They write in PNAS: "Even though rapid, short-term evolution often occurs in intervals shorter than 1 [million years], the changes are constrained and do not accumulate over time."
Science Daily summarizes:
[The study] determined that rapid changes in local populations often don't continue, stand the test of time or spread through a species.One might add that recent changes in human height are normally attributed to improved nutrition, not heritable changes that attributable Darwinian processes.
In other words, just because humans are two or three inches taller now than they were 200 years ago, it doesn't mean that process will continue and we'll be two or three feet taller in 2,000 years. Or even as tall in one million years as we are now.
"Rapid evolution is clearly a reality over fairly short time periods, sometimes just a few generations," said Josef Uyeda, lead author of the study.... "But those rapid changes do not always persist and may be confined to small populations. For reasons that are not completely clear, the data show the long-term dynamics of evolution to be quite slow."
You can call it evolution, if you choose, but "evolution before our eyes" turns out to be a strikingly mirage-like, passing affair. The real action, whatever lies behind it by way of an evolutionary mechanism, takes place on a vastly longer timescale: 1 to 360 million years. That's what people mean by evolution. Dawkins's Ugandan elephants, Croatian lizards and Trinidadian guppies are a flash in the pan, misleading and almost certainly meaningless in the context of the evolution debate.