When I visited Harvard last week, I had to visit the Museum of Comparative Zoology (MCZ), where I did my Ph.D. work. It so happened that the exhibits—the displays of skeletons and stuffed animals that typify a nineteenth-century zoology museum—lay between my office and the soda machine, so I had lots of opportunity to look at the displays. Here are a couple of things I photographed last week that bear on evolution:
These are specimens of the European hedgehog (Click to enlarge). It is in the order Erinaceomorpha, which includes Old World hedgehogs, moonrats, and gymnures. I do deplore the mass killing that fuels such displays: did they really need more than one? And did they think about the children? (They have baby lions in the displays that were also shot.)
This is the greater hedgehog tenrec from Madagascar. It is in the order Afrosoricida, along with tenrecs and golden moles. Although this and the hedgehog above were once thought to be close relatives, they are not closely related at all. In fact, as one commenter noted below the European hedgehog is more closely related to humans than to the greater hedgehog tenrec. Their resemblance of the two “hedgehogs” is in fact a remarkable example of convergent evolution, in which divergent ancestors evolve into very similar forms. Look at the remarkable resemblance!
Here’s a diagram from a PNAS paper showing their relationship: their ancestors diverged about 105 million years ago (just look for the common ancestor of the hedgehog [top] and the golden mole in the following phylogeny):
Finally, here I am pointing out the vestigial hindlimbs of a sperm whale suspended from the ceiling of the Museum. That was part of the evidence I gave in my lecture two days later. These bones are not connected to the rest of the skeleton, but have to be mounted by suspending them with wires. They serve no structural function, but occasionally continue to develop into structures that have discernible leg parts, like the femur, tibia, and tarsus. These are evidence for evolution: the evolution of whales from a terrestrial four-legged organism, and in whales the ancestral legs remain as tiny vestiges embedded in the muscle.
BTW, congratulations to the population geneticist Joe Felsenstein, who just turned 70 yesterday. Felsenstein, who has made substantial contributions to theoretical evolutionary genetics, has done the same for systematics in recent years. Joe studied at the University of Chicago under my advisor Dick Lewontin, and one of his claims to fame was being a radical during the SDS troubles in the sixties. I believe Joe sustained some injuries in the SDS-police fracas by being hit in the head with a brick.
h/t: Andrew Berry