To give a little equal time to other trophic levels, this Saturday we have a meadow vole, a member of the rodent family Cricetidae.
Nicknamed ‘Voley’, this Microtus pennsylvanicus was rescued from a mechanical access shaft into which it had fallen and become trapped. What many people think of as ‘field mice’, and what many house cats bring home, are actually voles: they can be distinguished by their short tails, and smaller eyes and ears compared to other mice. Evolutionarily, meadow voles are known for being geographically variable, with many described subspecies, including a number restricted to small islands off the coast. Since most of these islands are land-bridge islands, isolated from the mainland only since the post-glacial rise in sea level, the differentiation of the voles inhabiting them is quite recent. The most distinctive of these small island derivatives of the meadow vole is a distinct species, the beach vole, Microtus breweri, found only on Muskeget, a very small island to the west of Nantucket Island, Massachusetts. (My friend and colleague James ‘Skip’ Lazell calls it “defiantly” distinct from the meadow voles on nearby islands.) They have been isolated on Muskeget only 2000-3000 years, and are thus an example of rapid divergence. Jerry deals with the nature of species and species formation in chap. 7 of WEIT, and in much more detail in his 2004 monograph with H. Allen Orr, Speciation.
An interview with Jerry on evolution vs. creationism appears in the online pages of American Scientist. In the interview, Jerry talks mostly about his approach to teaching evolution based on 25 years experience, and how he applied that experience in the writing of WEIT. A couple of highlights:
…when you read Darwin, the thing that’s most fascinating is the evidence he musters in support of it. In talking with professional biologists and evolutionists, they didn’t ever learn why people thought evolution was true, because you’re not taught that in class. But I thought that that should be passed on to the students because of the second reason I wrote the book, which is the pervasiveness of creationism in this country. I wanted to educate the students so they know that evolution really happened, so they don’t really doubt that, but also to arm them against the forces of irrationality that were going to be impinging on them and society….
And so when I teach the stuff I teach it as sort of an object lesson in how to adjudicate between competing theories in science. And that’s the way I wrote the book, too. I’m constantly asking the reader, “How does creationism explain this observation? It can’t.” So it’s more than teaching the evidence; it’s teaching them how to discriminate between good science and bad science, and that’s a good lesson for students too.
On the Oxford University Press website for the book is a letter I wrote to Charles Darwin that was broadcast this month on BBC 4. You can find the printed version here, and the original oral version here.