Question

[james_davis_nicoll]

Could we duplicate this effect with mutagenic pollution or a sufficiently dirty nuclear war?

Comments

[scott-sanford.livejournal.com]

We may be dubious about calling women who live near a recreation area for young military men 'reproductively isolated'...but that's not the story RAH was telling.

[tandw.livejournal.com]

Now you made me go look it up; it was something that I specifically remembered RAH alluding to, but it had been a while since I read it. From "Starship Troopers," p. 124 of the Berkley paperback edition (January, 1983 printing):

But the descendants of those colonists won't evolve. Not much, anyhow. This chap told me that they could improve a little through mutation from other causes, from new blood added by immigration, and from natural selection among the gene patterns they already own--but that is all very minor compared with the evolutionary rate on Terra and on any usual planet.

The fact that "new blood added by immigration" is a small effect compared to native mutations suggests a couple of things: 1) the planet is relatively reproductively isolated, and 2) Heinlein's biology was dodgy at best.

[scott-sanford.livejournal.com]

I remember the passage too. Apparently exogamous relationships were hard for some reason, or maybe RAH just didn't think it through - certainly interstellar travel didn't seem all that hard in that setting.