Lucky Octopi

Last year I went to a fascinating symposium in honor of the great evolutionary biologist George Williams. The March issue of the Quarterly Review of Biology ran a series of papers written by the speakers at the meeting that offered much more detail on how Williams had influenced them in their various fields. Randolph Nesse of the University of Michigan gave one of the most interesting talks at the meeting on maladaptation and what it means to human medicine. You can download the pdf from his web site. To whet your appetite, here's a nice passage on the eye: "It works well when it works, but often it does not. Nearly a third of us have hereditary nearsightedness, and almost no one over 55 can read a phone book unassisted (except for those who have been nearsighted for decades!). The lovely mechanism that regulates intraocular pressure often fails, causing glaucoma. Then there is the blind spot, a manifestation of the abject design failure of nerves and vessels that penetrate the eyeball in a bundle and spread out along the interior surface instead of penetrating from the outside as in the betterdesigned cephalopod eye. Octopi not only have a full field of vision, but they need not worry about retinal detachment. They also need neither the tiny jiggle of nystagmus that minimizes the shadows cast by vessels and nerves on the vertebrate retina nor the brain processing mechanisms that extract the visual signal from the nystagmus noise. In short, the vertebrate eye is a masterpiece not of design, but of jury-rigged compensations for a fundamentally defective architecture."