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The Precambrian is an informal unit of geologic time, [3] subdivided into three eons (Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago to the beginning of the Cambrian Period, about 538.8 million years ago , when hard-shelled creatures first appeared in abundance.
The Precambrian dates from around 3850 to 542 million years ago. The Neoproterozoic is characterized by a large glaciation event, followed by the appearance of the first multicellular body plans before the Cambrian Explosion. Until the late 1950s, the Precambrian was not believed to have hosted multicellular organisms.
Charnia is significant because it was the first Precambrian fossil to be recognized as such. The living organism grew on the sea floor, 570 to 550 million years ago, and is believed to have fed on nutrients in the water.
1 Precambrian. 2 Paleozoic. 3 Mesozoic. 4 Cenozoic. Toggle Cenozoic subsection. 4.1 Selected Cenozoic taxa of Florida. 5 References. Toggle the table of contents.
List of extinct animals of Romania; List of fossil species in the La Brea Tar Pits, California, United States; List of fossil species in the London Clay, England; List of White Sea biota species by phylum, Russia; Paleobiota of the Hell Creek Formation, northern United States; Paleobiota of the Morrison Formation, western United States
Cambrian animals such as Waptia might have competed with, or fed upon, Ediacaran life-forms. Increased competition due to the evolution of key innovations among other groups, perhaps as a response to predation, may have driven the Ediacaran biota from their niches. [ 138 ]
The Avalon explosion, named from the Precambrian faunal trace fossils discovered on the Avalon Peninsula in Newfoundland, eastern Canada, is a proposed evolutionary radiation of prehistoric animals about 575 million years ago in the Ediacaran period, with the Avalon explosion being one of three eras grouped in this time period. [3]
Prehistoric life of the Precambrian Supereon; Subcategories. This category has the following 5 subcategories, out of 5 total. ...