evo-devo

This is pretty darn good for Stanford students! ;) Ready for the final?
From the first dawn of life, all organic beings are found to resemble each other in descending degrees, so that they can be classed in groups under groups. Isn't that a good sentence? It's the first of this chapter. There's music in the way the Biblical ring of "From the first dawn of life", falls towards the swallowed repetition of "groups under groups", which itself mirrors and explains the descending degrees of resemblance that gives the sentence its scientific filling. The next line is just as good: "This classification is evidently not arbitrary like the grouping of the stars in…
To a man with a hammer, said Mark Twain, everything looks like a nail. The better your hammer, I would add, the more nail-like everything looks. In natural selection, Darwin had crafted one of the best hammers of all time. And in chapter 5 of the origin, 'Laws of Variation', you can hear him umming and aahing about various alternative mechanisms of evolutionary change before deciding that, actually, you know what this needs...hold 'er steady...Thwack! How about, for example, the "effect of external conditions" -- "food climate &c.". Well, "Gould believes that birds of the same species are…