Evolution in Action

Ediacara Biota

The supercontinent Rodinia, which was centered at the South Pole, broke apart 750 million years ago. Laurentia, which included the future North America was carried southward and crossed the South Pole, while Baltica and Siberia drifted northward. 600 Ma, 570 Ma, 530 Ma, NA-centric animation

Because so much landmass had been carried toward the poles, much of Earth's land was ice-covered in the Late Precambrian. The Precambrian ended 543 million years ago, by which time diverse multicellular animals had already evolved and fossilized in the oceans.

Animations of Continental Drift from 750 to 540 Mya PaleoMap Project : from 750 Mya to present :

The Ediacara Biota, or Ediacaran Assemblage, named for the Ediacara Hills of South Australia, has been uncovered at more than 30 sites worldwide on all continents except Antarctica. The biota includes oval, frondose, and spindle-shaped forms of unknown affinity to later organisms.

Based on shared taxa in various localities, the fossil locations dating from the Vendian can be assigned to three groups:
(1) Newfoundland (Mistaken Point Formation) and Charnwood Forest, UK.
(2) Ediacara Hills (SA), Baltica, Siberia (White Sea) and NW Laurentia.
(3) Namibia, SW Laurentia, S. America and S. China.

The assemblage comprises marine life forms with fossils dating from the Vendian, which is the latest period of the Precambrian, to the basal Cambrian period of the Phanerozoid Eon – 620 to ~543 Ma. Thus, the Vendian assemblages comprise the oldest known fossils of multicellular organisms. Undoubtedly, multicellular organisms evolved well before their fortuitous fossilization in deposits that have since become exposed. Many of these soft-bodied creatures went extinct during the Cambrian "explosion", but some members of this biota, including primitive worms, survived. [more, images, images, images ]

Images of fossils : Charniodiscus arboreus : Aspidella terranovica : Dickinsonia costata : Parvanorina minchami : Spriggina floundersi :

Descriptions & images of fossils White Sea Region of Russia : Cyclomedusa : Charnia : Eoporpita : Nemiana : Pteridinium : Ediacara Hills of South Australia : Arkarua : Dickinsonia : Dickinsonia sp : Spriggina : Spriggina sp : Tribrach : Kimberella : Mawsonites sp : Medusinites sp : Glaessnerina sp : Charnia sp :

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