Iain Inkster:
>>> "The original organism is commonly supposed to have been a simple but
>>> effective self-replicating structure, whose descendants' methods of
>>> self-replication grew increasingly elaborate".
>>> ...I'd like to add that only some of the descendants evolves along
>>> those lines. But, I don't like " some the descendents of whom's
>>> methods ".
Bert Hutchings:
>> The original organism is commonly supposed to have been a simple but
>> effective self-replicating structure, some of whose descendants
>> evolved increasingly elaborate methods of self-replication.
Iain Inkster:
> Some of the original organism?
No, some of the descendants. Of course, all of the *other* descendants
died out, but you don't need to go into that here.
> I thought of that, and that's how I took it.
You mistook it. Bert's version is good.
The last part could be shortened a bit by dropping the repeat of
"self-"; it's reasonably obvious in this context.

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Mark Brader | "Design an idiot-proof system, and the universe
Toronto | will spontaneously evolve a higher grade of idiot
msb@vex.net | that is able to circumvent it."
My text in this article is in the public domain.