THE PERMIAN MASS EXTINCTION AND THE TRIASSIC RECOVERY

The most severe mass extinction of the Phanerozoic occurred by stages in the Permian and spanned several millions of years. The marine envir onment suffered the most since their ecosystems greatly collapsed unde r the joint effects of a great drop in sea level and general anoxic co nditions in the ocean. On the land, arid conditions and several brief episodes of climatic cooling led to a great loss in biodiversity of th e vertrebrate fauna and flora and therefore in the ground cover by the plants. in contrast, the insects did not seem to be very much affecte d by the crisis. The recovery of the disturbed ecosystems at the begin ning of the Triassic proceeded from refuges, such as the transitional environments between sea and emerged lands.