One nice thing about science is that it’s still done by people, so that you can see pretty much all the range of behaviors and attitudes in science that you’ll get at the most insane political gathering. Different proportions, maybe, but the same range. Thinking about various things like the wild-eyed political insanity that has gripped the GOP over the past few decades, and other things like the contentious issue of ‘Global Warming’, I was reminded of the controversy over the ancestry of birds. Over a century ago, with the discovery of Archeopteryx, it was proposed that birds are dinosaur descendants (BADD) – after all, take away the feathers from Archy and you’ve got just another small dromeosaur-type theropod. That didn’t last, of course – it soon became ‘common knowledge’ that birds could not have come from dinosaurs and therefore had to be descended from some other archosaur line. I suspect the need for that determination may have come from the prevailing view in the early part of the 20th century that dinosaurs were great, plodding, cold-blooded brutes which could not possibly have given rise to such zippy things as birds. When John Ostrom described Deinonychus in the 1960s, that view got a jolt – suddenly some dinosaurs looked active, speedy, even possibly warm-blooded. Bob Bakker took that idea and ran with it with notable success, being a photogenic kind of guy who wasn’t shy about publicity, and then John Horner’s dinosaur nesting discoveries and popularization of Armand de Ricqles’ dinosaur bone studies made dinosaur ancestry of birds look very plausible. The not-BADD camp naturally didn’t accept this sort of non-traditional thinking and set out to again find reasons why the apparently obvious could not actually be correct.
The original justification for this evolutionary impossibility, back in the early days of the 20th century, was that dinosaurs had no furcula (wishbone); not just that – they had no clavicles (collar bones) from which the furcula is formed. Whoops – turns out they actually did; those bones were there all the time, just damaged or misidentified. OK, then; well, no dinosaurs had feathers – that held up for a while until the Chinese sedimentary beds were opened up, that preserved dinosaurs in detail as fine as the Bavarian beds that gave us Archy, and from which we now know that a variety of theropods had feathers. Well, how about this: birds have a semi-lunate carpal in the wrist; dinosaurs don’t! So there, you think you’re so smart! Well, just as with the furcula, it turns out that the semi-lunate carpal was there all along, just misidentified or not always part of the skeletal remains. Each time The Reason is removed, another Reason is proposed to explain why birds cannot have come from dinosaurs, but what it boils down to is “We have our conclusion; we just have to find something to support it!” Never mind all the similarities, structurally, physiologically and even behaviorally; there must be a difference that will conclusively prove to us that it’s all simply an incredible level of convergent evolution! The latest Reason is that the reduced hands of birds have lost different fingers than the reduced hands of theropods. An interesting argument, certainly, but just as with all the other Reasons, one has to wonder why one factor (which may or may not actually be correct) should over-ride the myriad of other factors pointing in the opposite direction. The tricky bit, of course, is that what little we know about dinosaurs is based on what fossil evidence we can find. In the first place, this can often be somewhat inconclusive (even to the point of allowing multiple interpretations), and in the second place, people being people, it’s quite impressive how everything can be seen only in that way which supports our desired conclusion.
We humans have an immeasurable ability to see only what we want to and explain away or simply ignore anything that doesn’t fit our desired reality. You see it all around, in politics and the press; in sports and religion; in dating and marriage. We can even invent a reality to live in, and try to force the world to fit into it with us (usually with tragic results). Then, of course, the usual cry goes up: “I didn’t mean for this to happen!” “Nobody could have predicted this!” “It’s [somebody else]’s fault!”, but then, of course, it’s too late to do anything useful about it except try to clean up the mess as best possible and convince ourselves that we were completely correct, but that some bizarre fluke of history or act of God made things turn out this way, and nothing could have prevented it. ‘What a piece of work is man’ – not only do we not learn easily, we frequently get rid of what little we’ve learned, I guess because thinking makes our heads hurt.