The Permian–Triassic [/b]extinction event (250 million years ago) was a major turning point in the history of life of earth, that it is sometimes puzzling how little is known about this event by the general public. In this event, more that 96% (this figure varies from 90% to 99 %) of all lifeforms on the earth became extinct. It was so devastating that its effects were truly global. The cause of the event is not well understood, although candidate processes range from asteroid impact, to volcanism to, gaseous release from the oceans etc, etc. http://en.wikipedia.org/wiki/Permian-Triassic_extinction_event
One of the survivors of this event was an animal called [b]Lystrosaurus(http://en.wikipedia.org/wiki/Lystrosaurus). Take a look at your ancestor below: Is it not remarkable how life has been able to bounce back to the level of diversity that exists today?
Thank goodness for EVOLUTION.
1) "When Life Nearly Died, The Greatest Mass Extinction of all Time", Michael J. Benton.