Darwin Was Right, So They Say
In order to keep Darwin looking trendy, some evolutionists use the “Darwin was right” meme.
Darwin was right #1: invasive species: “Evolutionary imbalance hypothesis: On invasive species, Darwin had it right all along, study shows.” That’s the meme in action from a Brown University press release. The question should be whether Darwinism uniquely helped explain invasive species in ways other biologists did not, because the problem certainly predates Darwin, as any farmer would know. The article summary says,
Based on insights first articulated by Charles Darwin, professors at Brown University and Syracuse University have developed and tested the “evolutionary imbalance hypothesis” to help predict species invasiveness in ecosystems. The results suggest the importance of accounting for the evolutionary histories of the donor and recipient regions in invasions.
Here’s how the “evolutionary imbalance hypothesis” (EIH) is defined: “Species from regions with deep and diverse evolutionary histories are more likely to become successful invaders in regions with less deep, less diverse evolutionary histories.” The basic idea, say the two scientists (Sax & Fridley) featured in the press release, was first articulated by Darwin. “Darwin’s original insight was that the more challenges a region’s species have faced in their evolution, the more robust they’ll be in new environments.” This fit into Darwin’s ideas on competition: fighting for survival makes you stronger, or fitter. Species tested in the crucible of competition “consequently been advanced through natural selection and competition to a higher stage of perfection or dominating power.”
While it may sound intuitive, a question comes to mind: how can anyone know what challenges a species has faced in its evolution? If species robustness is measured by its success at invasion, the scientist would be reasoning in a circle. Sax & Fridley assume that the more diversity in a region, the more the species have competed and become robust; the more successful, therefore, they will be as invaders. This is old-school Darwinism, however. Many biologists now believe that nature can “let a thousand flowers bloom” in the same ecosystem without fierce competition.
Although Sax & Fridley found some confirming evidence in their studies, they also found anomalies, which they were able to explain away with auxiliary hypotheses. This opens their confident claims to criticisms of ad hoc theory rescue. Late in the article, this qualification appears: “Sax and Fridley acknowledge in the paper that the EIH does not singlehandedly predict the success of individual species in specific invasions.” If anyone were to use EIH to predict an outcome in a real-world situation, it appears anything could happen, and could still be explained a posteriori within the Darwinian model. How useful is that?
Darwin was right #2: Group selection: Without going into detail, we can note that “group selection” (natural selection acting on categories above the individual) has long been controversial. Steven Pinker criticized the notion as “a scientific dust bunny, a hairy blob in which anything having to do with ‘groups’ clings to anything having to do with ‘selection.'” Nevertheless, Jonathan Pruitt and Charles Goodnight are keeping it alive with new evidence, and giving the credit for their insight to You-Know-Who. Without saying “Darwin was right” verbatim in a press release from the University of Vermont, they imply as much in their research on spiders (among which they claim to have observed group selection in action).
In his 1859 masterpiece, On the Origin of Species, Charles Darwin puzzled over how ants could — generation after generation — produce workers that would serve the colony — but were sterile. Evolution by natural selection has often been understood to work at the level of the organism: the traits of an individual determine whether it will survive and reproduce. How could these sterile ants persist in nature, he wondered, if they didn’t reproduce?
“This difficulty, though appearing insuperable, is lessened, or, as I believe disappears, when it is remembered that selection may be applied to the family, as well as to the individual.” In other words, evolution by natural selection, Darwin thought, could operate at numerous levels, including groups: “A tribe including many members,” Darwin wrote in Descent of Man, who were able to “sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection.“
By implication, why can’t biologists today accept the fact that the Father of Evolutionary Theory thought of group selection first? What’s the problem? Darwin may have been right. If history is any guide, though, this decades-long controversy will not be resolved by a new story about spider personalities.
Darwin was right #3: Jump Dispersal: Another instance of the “Darwin was right” meme is found in this story from the National Institute for Mathematical and Biological Synthesis (NIMBioS). It deals with biogeography: how animals got from here to there. It’s a subject, we are told, that “has long been debated among biologists, especially in cases where organisms that are related live on distant continents separated by vast oceans.” (This might be a surprise to those who have long been told that biogeography provides strong evidence for evolution.)
More than one hundred and fifty years ago, Charles Darwin hypothesized that species could cross oceans and other vast distances on vegetation rafts, icebergs, or in the case of plant seeds, in the plumage of birds.
Though many were skeptical of Darwin’s “jump dispersal” idea, a new study suggests that Darwin might have been correct.
So does Darwin explain how large flightless birds got from Africa to New Zealand and South America? The only two explanations tested were (1) land bridges and (2) vegetation rafts, icebergs, or other unusual transport mechanisms (Darwin’s hypothesis). Jump dispersal was often doubted because it relied on rare, “near miraculous” events.
Nicholas Matzke, a staunch Darwin defender, developed a computer program that gives the edge to jump dispersal, allowing him to credit Darwin: in the computer model, “the jump dispersal pattern appears to be much more common,” he says. “It looks like Darwin was right after all.” It seems to have escaped his notice, though, that Biblical creationists have appealed to both mechanisms as consequences of the global Flood: (1) land bridges from a lowered sea level, and (2) vegetation rafts.
Here’s a puzzle for everyone. It was reported on PhysOrg: “If hippopotamuses can’t swim, how can some be living on islands?” That’s right; those big, fat “river horses” trot on the bottom of waterways, but are not known for floating or being distance swimmers. How come fossils of hippos have been found on distant islands, like Madagascar? “Experts say that widely accepted models for the methods, patterns, and timing of the colonization and dispersal to several islands (e.g. Cyprus, Crete, and Madagascar) may need to be reconsidered.” The article doesn’t rule out land bridges, but says that they “are not currently supported by positive geological evidence.” Matzke should plug “hippos” and “Madagascar” into his computer model and see if they were carried there on icebergs or by some other “near miraculous” event.
Sure, Darwin was right on occasion. He was right by chance sometimes, like the proverbial broken clock. He was right when he wasn’t left. He was right whenever he overlooked the implications of his theory and acted like a proper Victorian gentleman. It’s doubtful that will make much difference in the Great Judgment (see 11/30/05).