3 - 2.4
2.4 - 1.8
1.8 - 1.2
1.2 - 600
600 - 0
3 - 0
Quarternary Period 1.8 - Present
Pliocene Epoch 5 - 1.8
Pleistocene Epoch 1.8 million - 10 K
- 2.6 - 2 South Pole
- 3 116 Great years ago. Solar System revolutions around Sirius crossing the Galactic Plane.

Pliocene Epoch 5 - 1.8
Geologic - "Great Ice Age." Ice sheets and other glaciers encroach and retreat during four or five primary glacial periods. At its peak, as much as 30% of the Earth's surface is covered by glaciers, and parts of the northern oceans are frozen. The movement of the glaciers alters the landscape. Lakes, such as the Great Lakes in North America, are formed as ice sheets melt, and retreat. Global warming begins after the last glacial maximum, 18,000 years ago.
- 4 - 2 Australopithecus afarensis, Hominid species in Ethiopia
- 3 Bipedal australopithecines (early hominides) evolve in the savannas of Africa being hunted by Dinofelis.

Pliocene Epoch 5 - 1.8
Life Forms - The oldest species of Homo, Homo habilis evolves. The flora and fauna in the regions not covered by ice are essentially the same as those of the earlier Pliocene Epoch. Mammalian evolution includes the development of large forms: woolly mammoth, woolly rhinoceros, musk ox, moose, reindeer, elephant, mastodon, bison, and ground sloth.
In the Americas, large mammals, such as horses, camels, mammoths, mastodons, saber-toothed cats, and ground sloths, are entirely extinct by the end of this epoch.

- 2 Homo habilis, thought to be the ancestor of the lankier and more sophisticated, Homo ergaster, which in turn gave rise to the more human appearing species, Homo erectus.

- 1.9 - 1.2 South Pole

Pliocene Epoch 5 - 1.8
Geologic - The emergence of the Isthmus of Panama changes ocean circulation patterns and coincides with the formation of an Arctic ice cap. Plate tectonic interactions result in the uplift of the Sierra Nevada, formation of the Cascade Range, and onset of strike-slip faulting on the San Andreas Fault. In Europe, the Alps continue to rise.
The global climates become cooler and drier.

- 1.8 Homo erectus evolves in Africa. Striking resemblance to modern humans, but had a brain about 74 percent of the size of modern man.
- Nutcracker Man discovered in Tanzania by Mary Leakey
- Homo habilis or tool-making man
- 1.75 Dmanisi man, Homo georgicus (Georgia, Russia), tiny brain came from Africa, with Homo erectus and Homo habilis characteristics. Common genetic ancestor of humans and Neanderthal.
- 1.1 - 900 K South Pole

Pliocene Epoch 5 - 1.8
Life forms - Camels and horses are abundant throughout North America. Ground sloths also evolve and the Great American interchange between South and North America begins.
Primates continue to evolve, and the australopithecines, antecedents to Homo sapiens,develop late in the Pliocene in Africa.
In North America, rhinoceroses and ordeodonts become extinct.

- 1 Homo erectus begins to migrate to Europe and Asia

- 5 Sahelanthropus tchadensis Human ancestors speciate from the ancestors of the chimpanzees.