During the Proterozoic the first multicellular organisms evolved. Among the plants there were blue-green algae, possessing a more complex internal structure, and in the cell structure, a nucleus. Blue-green algae excreted limy substances, formed carbonate structures when they accumulated. These were called stromatolites.

Two large groups of organisms gradually evolved. One had the ability to synthesize organic substances from carbon dioxide and water under effect of solar rays (photosynthesis). The other consumed organic materials. A division of a the Plant and Animal Kingdoms had occurred.

In the late Proterozoic (about 1 billion years ago), the oceans were inhabited by invertebrate animals: sponges, primitive echinoderms, medusa (jellyfish), coelenterates (corals), worms, foraminifera, radiolarians and a numerous group - archaeocytes - which later became totally extinct. The best-preserved fossils of the animals of this time period were discovered in Southern Australia and on the coast of the White Sea.

Academician V.I. Vernadskiy investigated the role of the organic kingdom in life of the Earth and came to the conclusion that living substances played an active part in all geological processes on the surface of the Earth and in the formation of atmosphere.
 
 

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