Book Progress #17

I was intending to sit down and write about whale limbs yesterday afternoon (homology, hyperphalangy, and other neat stuff), but by the time I was ready to do it I was feeling so restless that I had to get out of the house. My wife and I headed out to catch a showing of The Incredible Hulk (which was actually pretty good), but I was thankfully still primed to write when we returned to the apartment. What I ended up writing just took a different course than I had expected.

As I thought about whale evolution on the way home from the theater I reflected upon the ways different lineages became adapted to life in the water. The two groups of living whales represent just two evolutionary alternatives; sirenians, otters, crocodylians, ichthyosaurs, plesiosaurs, pliosaurs, mosasaurs, sea turtles, and placodonts present a variety of other possibilities, the results of historical contingencies. The recent research that has revealed the role of contingency in the evolution of Escherichia coli got me thinking about convergence and diversity, as well, and contingency provided a good jumping-off point for my concluding chapter.

Contingency can be a somewhat muddy topic, often deemed to be more of a philosophical debate than a scientific one. More often than not I have seen John Maynard Smith's statements from a book review of Wonderful Life provided as a "safe" position, namely that there is no way to "re-run the tape" of evolution or to know if creatures like ourselves would have evolved had chance events in the past been different. If we can't directly test the idea then there's just no way to know, right? I can't say I agree that we have no way to test the idea, especially since the new E. coli paper presents important new observations that directly bear upon this topic. I believe that the debate is more than simply philosophical and that evolutionary history provides some clues that let us approach this argument more closely than is sometimes allowed. I've still got a lot of thinking to do and I want to be very careful with my wording, but I feel that historical contingency provides the best framework to hang my concluding remarks upon.

(New sections are in bold)

Introduction

Huxley's rejoinder to Wilberforce at Oxford - Darrow puts Bryan in the hot seat - Behe's astrological mishap - One long argument - Flickering candles in the dark - Monstrous myths - Evolutionary archetypes -

Horses

Darwin's problems with paleontology - Evolution, sure, but natural selection? - Gaudry and Hipparion - Kowalevsky and Anchitherium - Huxley's linear phylogeny - Wherefore art thou, Hyracotherium? - "A gift from the Old world to the New" - Marsh's "toy horse" - Huxley buried under bones - Ladder of horse evolution - Putting the litoptern before the horse

Whales

Koch's Missourium - Hydrarchos - The king of the seas flees to Europe - Maybe Basilosaurus, maybe not - Huxley's overlooked insight - Intercalary whales - The problem of whale evolution - Diphyly of whales? - 70+ years of Protocetus - An unexpected skull - But what did it look like? - Indocetus - Teeth: confusion and convergence - Mesonychids, Perissodactyls, and Artiodactyls - Telescoping - Toothed mysticetes - Aetiocetus

Avian Dinosaurs

Noah's ravens vacation in New England - Hitchcock's Jurassic birds - A little fossil birdie told me about evolution - A misplaced feather - From London to Berlin - The source of Huxley's inspiration - Megalosaurus = an ossified, fossilized, underdeveloped chick - The unimportance of Archaeopteryx - Hypsilophodon as a good transition - Problems with the Pachypoda - How did we get such beautiful fossils? - Ornithosuchus or theropods? - The case of the missing clavicles - 75 years of pseudoscuhian narrative - Barnum Brown's forgotten Daptosaurus - Ostrom's "terrible claw" - "Tetrapteryx" and Microraptor

Human Evolution

Tyson's dissection of a "pigmie" - A chimp's place in the Chain - Where are the "missing links?" - White's 1799 attempt to save the Chain - The intellectual Rubicon - Without language there is no thought - Glorified apes and lowly humans - Buckland's "Red Lady" - She's no lady - Where were the ante-diluvian humans? - Cave contamination - Brixham cave - An unequal partnership - Falconer's enthusiasm, Prestwich's skepticism - Evidence from abroad - Somme Valley turning point - 1859 - Complaints and queries - Pre-Adamites - The Neanderthal that was mistaken for an Irishman - The Neanderthal fossils get named - Dubois goes to Indonesia - Skull of an ape, leg of a human - "Java Man" - The transitional gibbon-man - The discovery of "Peking Man" - Dart's Australopithecus - An irrelevant ape - Le Gros Clark to the rescue - Osborn vs Bryan - Harold Cook's Mystery Tooth - Hesperopithecus = Prosthenops - What makes us human? - Ask a stupid question... - Ape-like humans, not human-like apes - Caught in the Chain

Conclusion

Troodon sapiens? - Walking with dinosaurs - Eerie similarity - Evolution doesn't close a door without opening a window - How can we know? - Unfamiliar ET's - Alternative apes - Little but a twig