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PRECAMBRIAN  Era

Precambrian era, Precambrian picture

Oil painting : 24" x 30"

 

PRECAMBRIAN ERA
The Earth's surface was formed some 4600 millions years ago. In its earliest solid form our planet was one vast inhospitable desert and looked very different from today. Peaks and hills were of sharper outline; slopes were more abrupt. Without atmosphere or water, there was nothing to weather the rocks and wash the debris down into the valleys; and without water-borne sediment there was no soil. But in places the Earth displayed very high volcanic activity. As the crust was constantly broken down and remade, whole regions rose and sank.  New rocks appeared, only to be remelted, so that their entire structure altered. 

Some 4000 million years ago dense clouds hung over the bare Earth, often blocking out the sun's light. The Earth's surface experienced gigantic storms, while streams of molten lava gushed forth in many places. Volcanic activity released increasing amounts of gas and vapor from inside the Earth and these gradually formed an atmosphere too heavy to escape into space. Water began to appear in depression in the Earth's surface, first as pools, than as large sheets of water. In time these united to form the first oceans, while heat and cold, wind and water, disintegrated the rocks and produced the first sediments. Life itself did not yet exist, but the organic compounds needed to build living matter were already present.

Life originated on Earth about 3500 million years ago. In time, the first plants appeared, followed by the first invertebrates (animals without backbones). By about 2000 million years ago the shallower seabed was covered with different primitive single-celled organisms. These included blue-green algae, simple prokaryotes that marked an enormous step forward in the evolution of life, since they contain a complex green pigment called chlorophyll. This enables plants, using the energy of sunlight, to manufacture substances from non-living matter, such as carbon dioxide and water, for their food. In the process known as photosynthesis, green plants release oxygen, probably not present in the atmosphere before their time.

  

TIME - 4600-570 Million Years Ago


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Precambrian period
Cambrian period
Ordovician period
Silurian period
Devonian period
Carboniferous period
Permian period, Dimetrodon
Triassic dinosaur
Jurassic dinosaur pictures
Cretaceous dinosaur pictures
Tertiary prehistoric animals
Quaternary prehistoric animals

 

       

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