Adjacent Words

Pleistocene epoch definitions

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WordNet (r) 3.0 (2005)

n
1: from two million to 11 thousand years ago; extensive glaciation of the northern hemisphere; the time of human evolution [syn: Pleistocene, Pleistocene epoch, Glacial epoch]

Britannica Concise

Earlier and longer of the two epochs that constitute the Quaternary period. The Pleistocene began c.1.6 million years ago and ended c.10,000 years ago. It was preceded by the Pliocene epoch of the Tertiary period and followed by the Holocene epoch. At the height of the Pleistocene glacial ages, more than 30% of the land area of the world was covered by glacial ice; during the interglacial stages, probably only about 10% was. The animals and plants of the Pleistocene began to resemble those of today. Flowering plants proliferated, and new groups of land mammals, incl. humans, appeared. At the end of the epoch, mass extinctions occurred: in N. America more than 30 genera of large mammals became extinct within a span of roughly 2,000 years. Of the many causes that have been proposed for these extinctions, the two most likely are changing environment with changing climate and disruption of the ecological pattern by early humans.