On land, the dawn of the Triassic Period was dominated by Lystrosaurus, a tusked, pig-sized mammalian reptile that ruled Earth until other, and ultimately much larger, species displaced it. In the ocean, it is the transition from the dawn ecosystem to modern organisms, wiping out 300 million years of history. Dinosaur Extinction Page Dinosaur Extinction Page There have been many mass extinctions throughout the history of the Earth. The Comet's Tale Everything you ever wanted to know about comets. Citizen's Protection against NEOs Colorado-based group keeps an eye on the night sky for Near Earth Objects.
Visitors can find membership info, recent news, and collision updates.
Doomsday Asteroid - Nova Online Explore the farthest reaches of space with this PBS site and learn more about asteroids, comets, meteors, and their relationship to Earth. May we live long and die out. Thank you for not breeding. Resources FAQs about The Solar System. Extinction Extinction Extinction occurs when all living representatives of a group die out.