My personal favorite is from 1724, when Giovanni Domenico Santorini, an Italian anatomist, claimed the appendix was a natural habitat for intestinal worms, saying, "It is necessary for these animals to have a warm and quiet place in which to live and it is not at all improbable that the vermiform appendix provides such a refuge, for they could not live where there are powerful peristaltic movements or a large quantity of fecal matter. They breed in the appendix in much the same manner as fish lay their eggs in tranquil waters rather than in flowing streams."Caspar Bauhin speculated that the appendix was a receptacle for a fetus's feces during gestation, a kind of mini-outhouse.
This was an important clinical finding, and Parker started to wonder about those who had their appendixes out: How did they recover from infections? Parker and collaborators found that patients without appendixes could be at a higher risk of not recovering. One group without appendixes had a two-fold increase in recurrent C. difficile-associated colitis. Parker thinks that other diseases associated with an altered microbiome would probably be similarly common among people missing their appendixes.The appendix is a reservoir for good gut bacteria—something Darwin could have never guessed, since he lived long before scientists came to acknowledge the existence of the human microbiome.
Discovering a function of the appendix—despite what the creationists said—didn't actually resolve the question of vestigiality. Was the appendix a leftover that was being put to another use? Or did it evolve specifically to perform the function it was serving? To find out for sure, Smith and Laurin and their colleagues built an evolutionary tree of 533 mammal species, using anatomical data published in previous literature.Then, using computational and statistical techniques, they could ask the questions Darwin had been unable to: Which mammal species had appendixes? How many times had the appendix evolved, and was it more than would be expected due to chance alone? If a species did have an appendix, how big was it? What shape was it?""Honestly," Parker says, "if it weren't for the creation scientists, I probably never would have looked at it further."
I reached out to several of the creation sites for a response to the allegations that they misinterpreted Parker and his colleague's work. Joel Tay from Creation.com wrote back to me: "Our article simply noted that Parker's work overturned previously held evolutionary assumptions which had been confidently asserted as a refutation of creationist ideas." Tay says that since they acknowledged the scientists believed their findings had an evolutionary explanation, "we would dispute the idea that we misused Parker's research."A Creation.com article on Parker's work is titled "Appendix shrieks creation."Glenn Branch, the Deputy Director of the National Center for Science Education, says that the appendix and all similar scenarios "play into a creationist narrative in which the evidence for evolution presented in textbooks is shaky or conjectural at best, or the product of hoax and conspiracy at worst.""The creationists have misinterpreted, either mistakenly or deliberately, our work," Laurin says. "I was horrified when I found out what they wrote about my paper."