Triassic: At the end of the Triassic, Pangaea began to rift apart

In many ways, the Triassic was a time of transition. It was at this time that the world-continent of Pangaea existed, altering global climate and ocean circulation. The Triassic also follows the largest extinction event in the history of life, and so is a time when the survivors of that event spread and re-colonized.

The organisms of the Triassic can be considered to belong to one of three groups: holdovers from the Permo-Triassic extinction, new groups which flourished briefly, and new groups which went on to dominate the Mesozoic world. The holdovers included the lycophytes, glossopterids, and dicynodonts. While those that went on to dominate the Mesozoic world include modern conifers, cycadeoids, and the dinosaurs.

The super-continent of Pangaea, mostly assembled by the Triassic, allowed land animals to migrate from the South Pole to the North Pole. Life began to re-diversify after the great Permo-Triassic extinction and warm-water faunas spread across Tethys.

Pangaea was assembled piece-wise. The continental collisions that lead to the formation of the super-continent began in the Devonian and continued through the Late Triassic.