Proterozoic(redirected from Proterozoic era)
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Of, relating to, or being the most recent of the two divisions of Precambrian time, from about 2.5 billion to 542 million years ago, marked by the formation of stable continents, the buildup of oxygen, and the appearance of the first multicellular eukaryotic life forms. See Table at geologic time.
The Proterozoic Eon.
(Geological Science) the later of two divisions of the Precambrian era, during which the earliest plants and animals are assumed to have lived. Compare Archaeozoic
(Geological Science) of or formed in the late Precambrian era
Prot•er•o•zo•ic(ˌprɒt ər əˈzoʊ ɪk, ˌproʊ tər-)
1. noting or pertaining to the latter half of the Precambrian Era, from about 2.5 billion to 570 million years ago, when bacteria and marine algae were the principal forms of life.n.
2. the Proterozoic division of geologic time or the rock systems formed then.
[1905–10; < Greek prótero(s) earlier, prior + -zoic]
The later of the two divisions of the Precambrian Eon, from about 2.5 billion to 540 million years ago. The Proterozoic was characterized by the buildup of oxygen in the atmosphere and the appearance of the first multicellular eukaryotes. See Chart at geologic time.
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|Noun||1.||Proterozoic - from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organisms|
|Adj.||1.||proterozoic - formed in the later of two divisions of the Precambrian era; "proterozoic life forms"|
geology - a science that deals with the history of the earth as recorded in rocks
early - at or near the beginning of a period of time or course of events or before the usual or expected time; "early morning"; "an early warning"; "early diagnosis"; "an early death"; "took early retirement"; "an early spring"; "early varieties of peas and tomatoes mature before most standard varieties"