[js1138]

I have to say that's the clearest statement of your position I've seen. Much to think about. I disagree at most points, but find it interesting. The lack of new body plans could reflect competition. If body plans originate in the transition from single-celled to multi-celled, then it would be difficult for new types to emerge without being eaten. And for modern organisms to alter their body plan would involve a major breech of Dollo's Law.

Lot's of people have spent lots of decades looking for nonrandom variation without finding it. I've seen FReepers argue that most mutations are harmful, but then the chances against a germ cell achieving conception are a hundred million to one. There's an enormous selection factor prior to birth, much greater than after birth.

[Alamo-Girl]

Thank you so much for your reply! Truly, I wish I had more time to respond, but I must leave to go stain this afternoon.

I just wanted to mention one thing concerning your remark about the inability to find evidence of nonrandom variation. You might find the interviews and discoveries by Gehring concerning master control genes - in his case the evolution of eyeness across phyla - to be illuminating. Ditto for Peter Weiss' commentary on "how the eye got its brain". More later...

[Doctor Stochastic]

After sacs and tubes, what's new in body plans?

Of course, all the angiosperms and gymnosperms post-date the Cambrian.