Chicken or egg? Neither!
Whenever I get asked about the chicken and egg problem, my mind invariably wanders back to those precursors of both chickens and eggs, namely the dinosaurs.
I've always had a fascination with dinosaurs (nothing unique there, eh?) and when I was quite a bit younger thought I might become a paleontologist when I grew up. The problem was that I never grew up, but that's another story.
I was still but knee high to a jackalope when I concluded that dinosaurs and birds were, in fact, the same. It was hard to avoid that conclusion when living with a variety of parrots who stalked around the premises like miniature T-Rexes, complete with bipedal locomotion, large claws on the end of scaly toes, and so forth. The lack of arms to grab with wasn't a problem – T-Rex himself had pretty much useless arms – not much better than the feet that whales have (you did realize that whales still have their foot bones inside all that blubber, didn't you?).
Well, the keen thing is we've known for a long time that oftentimes fetuses will display ancient traits during their development that don't persist during development. And Jack Horner, the dino-guy who revolutionized our understanding of nesting/social behavior of dinosaurs through his research into Maiasaurs, has a nifty new book that describes what some people are doing about it. Namely trying to recreate a dinosaur.
The book is How to Build a Dinosaur: Extinction Doesn't Have to Be Forever and in it Jack covers the fields of molecular cell biology, paleontology and a few other ologies to explain how, by keeping a gene from stopping the chicken from growing a tail while in the womb, the chicken will, presumably, grow one. Apparently all the wiring is there for arms, tails, and so forth. Seems that the easiest path for evolution to take was simply to start with the old model (dinosaur) and add a few genes that said "no tail" as the baby chicklet was in the process of forming. Get rid of the stop sign and there you go.
There's a very short interview on 60 Minutes that you can watch if you're interested in the super duper Reader's Digest form, and you can see it here.. Or you can ask your friendly neighborhood bookstore to get you a copy of How to … and learn all about it in detail.
- And that's today's word from the bird
