well, there are a lot of "local maxima" on the evolution phase space hypersurface. It takes catastrophes, like the K/T meteorite, or even the fact that the system is chaotic resulting in random sporadic mass extinctions, to knock species off their local max (or move the local max out from under them, actually, the shape of the surface changing), possibly to a deep valley where they die out, or maybe to a bigger hill where they can move upward farther.

So, a fly need not evolve more intelligence if it is at a local max in its environment. Enough catastrophes, and the likelihood of something evolving lots of intelligence increases (in the long run, and I mean really long run, because there are lots of short term (many millions of years) setbacks).

There's a hill out there with humans' names on it, and it took a few meteorites and a lot of years to bump some monkey onto it.

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Todd (Bowie, MD, US, North America, Earth, Sol System, Vega region, Local Bubble, Orion arm, Milky Way Galaxy, Local Group, Virgo A Cluster, Virgo supercluster, the universe in which spock is clean shaven)

Quidquid latine dictum sit, altum sonatur.

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