Scott Badger wrote:
> Huh? If all lfe is destroyed by the GRB, _and_ life starts up again on
> the planet, a few hundred million years isn't going to be enough
> time for space faring levels of intelligence to arise, is it?
>
> Surely this fact did not escape him. So what aspect of his theory am
> I not getting?
A GRB won't destroy *all* life. It would cause a mass extinction, killing all land-dwelling life on one hemisphere of the planet and (through indirect effects) a lot of other life in other areas. It might or might not manage to kill off land animals on the shadowed side of the planet (by suddenly destroying the ozone layer and atmospheric composition). In any case, a great deal of life will survive in the oceans.
If GRBs occur every few million years, complex animal life probably can't evolve. If it happens every few tens of millions of years, it evolves but doesn't have time to get very far. According to the theory, the gap between successive bursts has only recently become long enough for life forms like us to evolve.
I'm not sure if I buy all this or not.
> Besides, Jay Gould once stated that the contingency based character of
> natural selection was such that if evolution were replayed millions of
> times, intelligence would not appear on the planet. This was in
> stark contrast to my up-till-then cherished theory that attributes such as
> increased levels of awareness, neural complexity, and consciousness would
have
> good survival value. Point being, Dr. Annis seems to assume that
> if life appears on a planet, intelligent life is a highly probably
outcome.
> Gould assumes the opposite.
Combining 'rare intelligence' with GRB extinctions would certainly make us rare, though.
I don't think I but Jay Gould's idea, however. Look around. Recently evolved types of life (mammals, avians) seem to be much smarter than older ones (reptiles, fish). There are lots of unrelated species that are smart enough to make people worry about whether they are sentient or not (apes, whales, dolphins, elephants, and a couple of species of birds). The combination of tool use, intelligence and a capacity for large-scale social organization might be unusual, but there seems to be a clear trend towards increasing intelligence.
Billy Brown, MCSE+I
bbrown@conemsco.com