There have been five major mass extinctions in the history of life since the Cambrian. The “Big Five” are the Ordovician-Silurian, Late Devonian, Permian-Triassic, Triassic-Jurassic, and Cretaceous-Tertiary events. The latter is the most famous, having resulted in the extinction of all dinosaurs except birds, and more than half of contemporary biodiversity overall. This was not the most severe pruning of the tree of life, however — rather, this took place at the end of the Permian when roughly 95% of species were extirpated. The causes of the so-called “Great Dying” remain a subject of debate, but some recent work has provided evidence for an asteroid impact (perhaps in combination with various other related or independent factors).
Anyway, the reason I bring this up is that I am trying to find out the source film for the following clip by National Geographic:
If you happen to know the title of the documentary, let me know.
Oh, and if you’re interested in the End Permian event, you can take a look at these fine books: