Question: What do you do when a theory logically predicts both (a) and not (a)?
Answer: Apparently you heavily promote it.
MSNBC recently published two articles promoting Darwinian just-so stories to the public. The first article about the evolution of Waterfowl genitalia contends, “Scientists had speculated that male waterfowl evolved longer phalluses to give them a competitive edge over those not as well-endowed when it came to successfully fertilizing females.” That makes sense, I suppose. But the article makes one admission that strikingly contradicts that little just-so hypothesis: “Most birds lack phalluses, organs like human penises. Waterfowl are among the just 3 percent of all living bird species that retain the grooved phallus…” If long phalluses are so advantageous for reproduction, why did so many birds supposedly lose them? Darwinists will look back retroactively and claim that under the environmental conditions or sexual selection pressures experienced by most bird species, long phalluses weren’t advantageous. The problem in so doing is that they now have a theory which can explain both (a) long phalluses, and also not (a).
Now, if (a) is the statement “The long phallus of the male waterfowl is the product of an evolutionary arms race with female waterfowl,” then I’m afraid the negation of (a) is not the statement “The males of most bird species lack phalluses.” That’s basic logic.
As for the broader point, yes, evolution can, in certain cases, explain the presence of a particular anatomical structure in one species and its absence in a closely related species. That is because (a) there is an element of chance in the evolutionary trajectory taken by some particular population of organisms and (b) there is no such thing as the absolute fitness of a trait, so that traits that are fitness enhancing in one environment might be neutral or fitness reducing in another. In the present situation most bird species probably found that there was no advantage to be gained from having a long penis, and consequently found it better to direct its resources elsewhere. But some chance variation in an ancient population of waterfowl caused the females to prefer long penises, and the evolutionary arms race was on.
This is not a defect in evolutionary theory, it is merely a reflection of how nature is. It’s not Darwin’s fault that the course of evolution in the long-term is unpredictable. Luskin may as well excoriate nuclear physicists for being able to explain both the decay and the non-decay of a particular nucleus in a radioactive sample. What is interesting in the MSNBC article is that we now have some tangible evidence that it a sexual arms race lay behind the evolution of the waterfowl penis:
In most birds, the vagina or oviduct is a simple tube. However, in some waterfowl, there are sacs in the sides of this tube, pockets that are just inside the opening of the oviduct. These sacs appear “to function as ‘dead-ends,’ or false passages,” Brennan said. “If the phallus were to enter one of these sacs, it would not progress further into the oviduct where it would deposit sperm more effectively.”
Waterfowl oviducts can also possess a series of tight, clock-wise spirals. “Interestingly, the male phallus is also a spiral, but it twists in the opposite, counterclockwise, direction,” said Yale ornithologist Richard Prum, one of Brennan’s co-authors on the research. “So, the twists in the oviduct appear designed to exclude the opposing twists of the male phallus,” behaving like the opposite of a lock-and-key system.
The number of sacs and spirals in the reproductive tract of various female waterfowl seems to increase as the male phallus gets longer across the 14 different species of ducks and geese tracked by Brennan and her colleagues.
“I became very good at predicting what the genitalia of one sex would look like by looking at the other sex first,” Brennan said.
This suggests the genitalia of males and females have evolved to surpass each other in a kind of escalating arms race over which sex gets to control reproduction.
Interesting stuff. I recommend reading the rest of it.
This criticism is especially rich coming from Luskin. Seeing as how there is absolutely nothing that can not be explained with reference to a whimsical, omnipotent designer, I’d say Luskin should heed the advice typically given to those who live in glass houses. If he believes evolutionists are being arbitrary in their explanations of bird genitalia, perhaps he can show us how ID provides a superior explanation for the same set of facts.
Not content to be foolish just once, Luskin repeats his vapid criticism with regard to this article also at MSNBC, about the evolution of bipedalism. I’ll leave that one as an exercise to the reader.