There's some interesting news about the great Permian extinction event of 250 million years ago. It was probably the largest mass extinction in the planet's history, wiping out 70 percent of land species and 95 percent of species in the oceans. The causes of the Permian extinction are still a little unclear -- there was massive volcanic activity going on (the Siberian Traps), there may have been an impact with a Giant Rock From Space, there may even have been an ice age going on.
But that's all old news. The cool new stuff about the Permian Event is that it appears to have permanently changed the structure of ocean ecosystems. Before the Permian extinction, ocean ecosystems were apparently quite simple, based mostly on stationary filter-feeder organisms. Afterwards, they shifted to complex systems of mobile food-gatherers, a pattern which has continue to the present (despite a couple more mass extinctions along the way).
The harsh conditions of the Permian extinction apparently gave creatures which could move around to gather food an advantage over stationary organisms. (Obviously there are still plenty of stationary organisms in the ocean, but now there are also lots of mobile ones.) And, of course, we are descended from those complex mobile organisms. Without the Permian Event, we wouldn't be here.
This may have some relevance to the Fermi Paradox: perhaps planets which don't have periodic mass extinctions never develop complicated life forms capable of evolving intelligence.