Re: predictions if wave passed here

Date: Tue Oct 17 2000 - 22:26:42 MDT

Eugene writes, quoting Robin:
> > my model. Specifically they are how fast resources available can grow
> > at an "oasis", how much seeds cost as function of their speed and hardness,
> Resources growing at an oasis? The matterenergy concentration in a
> given solar system is constant. You can rearrange matter so that you
> maximize available energy flux utilization, or even tinker with the
> rate of matter to energy conversion. But the total resource
> concentration is finite.

I think Robin is referring here not to raw materials, but to processed
materials ready to be turned into finished product. This feeds into
the question of how quickly the replicators could build new seeds and

> > My model says that a selection effect at the leading edge selects for
> > pioneers who do not stay. So the big question is how strong this
> Inoculate an infinite agar plate. Step back a couple of lightminutes,
> and wait until the front will arrive. Look just behind the wave. Are
> you going to see sterile substrate after wave front? Fat chance.

My feeling is that once the wave has passed you by, evolution is through
with you. All the factors that got you here are irrelevant now.
It is very analogous to an organism which has lived past the age at
which it can reproduce. Selection pressures no longer act to keep such
organisms alive, for exactly the same reason.

In other words, if the fastest way to expand is to build fast in some
kind of catastrohic mode which will kill the organisms which stay behind,
that is what will evolve (eventually). If the fastest way to expand
happens to leave organisms behind, then that is instead what will evolve.

Selection/evolution plays no part in determining the fate of colonies
which have fallen behind the wave. Their behavior is unselected-for.
There is no selection pressure to favor colonies which hold onto the
systems after launching seeds (once the frontier has become unreachable).

> Staying is default. The launchers can't launch themselves, so they
> stay. Sustainable barrage of stellar neighbours with seeds is a waste
> of resources after they're infected, so they'll cease.

The behavior of the launchers after the frontier has become unreachable
has no effect on the rate of spread of the frontier, hence this kind of
reasoning cannot play a role in the selection of the fastest-spreading

> I think one half of your assumptions is faulty: yes, the selection
> effect is very strong, resulting in convergent evolution of expansion
> wave front organisms and no, they do not leave sterile substrate in
> their wake.

Sterility is a possibility, but many other behaviors are possible as well.


This archive was generated by hypermail 2b30 : Mon May 28 2001 - 09:50:17 MDT