peter jay stein, md, ma
This 54 page synopsis of the evolution
of the Earth, the origin and progression of life, and the
emergence of humans as descendants of the hominin lineage, divides the last 4.57 billion years into progressively overlapping, imagistic, time segments, to outline our place in biological existence.
Emergent Permian Period: 299 - 252 mya
Features of the Permian period: 299 - 252 mya:
the 6th (final) period of the Paleozoic era
1) Reptiles diversified and dominated both herbivorous and carnivorous terrestrial organisms.
2) The Permian extinction, "...a complex environmental catastrophe and mass extinction of life...," (The Geologic Time Scale, 2012, p. 682) leads to 95% extinction of marine organisms.
3) The supercontinent, Pangea, is complete, as Siberia (of Laurasia) collides with northern Euramerica, forming the Ural Mountains, while the southern latitudes are comprised of the compression of future South America, Africa, India, Australia, and Antarctica.
4) Mammalian ancestors, the therapsids, begin to evolve.