EarthÕs
most recent major ecological catastrophe...
...occurred
65 million years ago.
The fossil record
changes abruptly before and after this moment. It indicates that the dinosaurs
disappeared at this time. In addition, the majority of other
ocean and land animals went
extinct.
What happened? The evidence supports the idea that the earth was
struck by an asteroid. Asteroids
are constantly
colliding with planetary bodies, as evidenced by craters on their
surfaces.