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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 Paleocene Epoch: 66 - 56 mya
Features of the Paleocene Epoch: 66 - 56 mya
This epoch follows the Cretaceous-Paleogene, "K-T" Dinosaur extinction event.
% of marine (ocean-dwelling) animals that went extinct approx 66 mya
(data from The Cretaceous-Paleogene Mass Extinction, Royal Tyrrell Museum of Paleontology, youtube):
90% primary producers (microscopic plankton);
< 20% bony and cartilaginous fishes (mostly the larger, predatory fishes);
100% belemnoids and ammonoids
100% rudists and inoceramids
100% mosasaurs and pleisosaurs
% of terrestrial animals that went extinct:
> 90% birds
83% lizards and snakes
100% avian dinosaurs
6) tropical and subtropical climate extends to the polar regions.
4) Mammal fossils are scare or absent, most species reconstructed only from their fossilized teeth.
2) Mammals first appeared in the late Mesozoic era, during the late Triassic period, small, nocturnal insectivore, mammals as the dinosaurs dominated terrestrial life.
3) Once the dinosaurs vanished, mammals occupied the now vacant ecological niches, although birds survived as well.
Primate fossils date back to approximately 60 mya, emerging from a superorder, Euarchonta. The suborder Plesiadapiforms demonstrates ancestral primate features, although not a direct relation to Eocene prosimians and primates; they were nocturnal, arboreal, insectivore, shrew-like animals, resembling lemurs or tarsiers, developing: specialized hands for grasping, with 5 digits, opposable thumbs, and nails instead of claws (Carpolestes, or Carpolestidae); shoulders with rotating joints; three-dimensional, stereoscopic vision; a petrosal bulla; and a larger brain.
5) Turtles (anapsids) survived the K-T extinction event, whose lineage extends back 230 mya.
1) Epoch of the first radiation of placental mammals.
7) Rocky Mountains form during the Paleocene.
8) Europe, N. America, Asia are connected
9) Australia, S. America, and Antarctica are connected.
10) India has not yet migrated to Asia
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