system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When Dinosaurs went extinct, how can scientist say that they evolved into birds?

I'm no expert but doesn't an E.L.E. (extinction level event, thanks Deep Impact) pretty much wipes out everything that can't survive? Wouldn't it take a really really long time for a Dinosaur to evolve into a birds as we know it today? Wouldn't they have died out long before they had a chance to?

Edit: Thank you for dropping knowledge asteroids on me!
gpt
The extinction event that we describe as wiping out dinosaurs didn't kill everything. At the time there were dinosaurs that were markedly birdlike. Some of these survived, and have subsequently evolved into the modern form of what we call birds today. 

If you wanted to be technical, you can in fact say that dinosaurs are not extinct, as birds would thus qualify as dinosaurs. 

Likewise, small shrew like antecedents to modern day mammals survived, evolving into the mammalia we see today, including ourselves. 

The extinction event did not 'reset the clock' back to the origin of life, essentially, it simply eliminated a significant amount of the existing species.