Comments on: Daily (intermittent) Open-Ended Puzzle: Skull-brain evolution

By: Greg Lloyd

Greg Lloyd — Fri, 29 May 2009 17:05:03 +0000

I don’t know the answer to your evolutionary question. Aside from that I have a hard time getting around the deeply disturbing implications of more intelligent and persistent squirrel kind.

By: James

James — Fri, 29 May 2009 16:02:01 +0000

It’s been a while since I read “The Plausibility of Life” but I recall that Kirschner et al describe how the growth signaling of fetal structures are interelated so that yes, a change/mutation in one area (eg, skeletal structure) will trigger appropriate changes in the formation of muscle, vascular structure, skin, etc. My foggy layman’s description – not so much controlled by the same gene, but some systems use (I’ll call it) second-order signaling to conform to the fundamental genetic signals. So no, you don’t necessarily need multiple, coordinated changes in genes to trigger useful mutations.

By: Andy Weinberger (yes, I am related)

Andy Weinberger (yes, I am related) — Fri, 29 May 2009 03:02:19 +0000

With respect to evolution, I have no direct answer. Actually, it would be easier if I didn’t believe in evolution. But, non-evolutionarily (?), in infancy if the head contents enlarge, as in hydrocephaly, the skull enlarges to contain it, at least until the skull “joints” grow together in ossification.