The Precambrian Time

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The Precambrian Time. Felipe González . Valentina Stozitzky. María Alejandra Vargas . Daniela Ramos. Daniel Pérez. 10B. 4.5 billon years ago. The earth was born!!!. Geologists and paleontologists. Stop! Notice fabulous table on your book. Geologic time scale. - PowerPoint PPT Presentation

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The Precambrian Time

Felipe Gonzlez.Daniela Ramos.Mara Alejandra Vargas.Daniel Prez.Valentina Stozitzky.10B

4.5 billon years ago

The earth was born!!!4Geologists and paleontologists

Geologic time scale-relative, absolute dating.-major divitions of the geologic time scale. Eons

Stop! Notice fabulous table on your bookEraPeriodsPRECAMBRIAN It means before the cambrian period. Before the formation of rocks with recognizable fossils.Cryptozoic or "obscure life.90%

term was originally used to refer to the whole period of earth's historythere are some hard-to-discern fossils in some Precambrian rocks"crypt" = "hidden," and "zoon" = "lifeIt covers almost 90ofthe entire history of the earthDivided into three Eons



Precambrian Environment

The atmosphere was reduced into gases and oxygen.The planet had a redish tint.The seas had a green bright tone.

Oxygen began to be produced in large quantities.Oxygen had chimical reactions: Iron and oxidable surfaces.The planet developed a solid crust that created water vapor.Scientist think that seas were created by a volcanic catalist.When evolving life forms developed photosynthesis, oxygen began to be produced in large quantities, causing an ecological crisis sometimes called the Oxygen Catastrophe.Older rocks contain massive banded iron formations that were apparently laid down as iron and oxygen first combined

Important infoScientists think the first seas gave rise to life.

hot, mineral-rich volcanic vents actied as catalysts for chemical reactions .

Other bubbles contained self-replicating substances.The water bubbles that formed-1st cell membranes.

chemicals around them combined to produce energy-using, living cells.

The first living organism were microscopic bacteria founded in fossils.Fossilized bacteria and blue-green algae 3,500 million years ago.Eukaryotic cells2,100 million years after.Protozoa.Found mainly in the oceans.Forms of life

Invertebrates.Evolved later on (700 million years ago)

Sponges, corals, jelly fishHADEAN EONFrom 4567 to 3800 mya.

Formation of the Solar SystemFormation of the Earth.Moon is created.Oceans of liquid rock, boiling sulfur, and impact craters everywhere.The air is hot, thick, steamy.No oxygen -water vapor.-carbon dioxide.The big bangSplashh!No rocks of this time have been found.

ARCHAEAN EONFrom 3800 to 2500

Surface of the Earth molten solid rock.Water condensed in liquid form.

15 hours long. 1st Prokaryotes appeared.-oxygen producing bacteria.- cyanobacteria (blue-green algae).Atmosphere (75% nitogen,15% carbondioxide.)

The continents have not formed yet. (global ocean)PROTEROZOIC EONFrom 3800 to 2500 Divided in Era and Periods

Paleoproterozoic Era Siderian Period - Stable continents first oxygen is found -oceans and atmosphere.Oxygen catastrophekilled many organisms.Start of Huronian ice age.PROTEROZOIC EONFrom 3800 to 2500

Rhyacian Period - Organisms with mitochondria capable of aerobic respiration appear.Orosirian Period - Mountain development- Oxygen starts accumulating in the atmosphereStatherian Period -single-celled life appeared.- lots of bacteria and archaeans.PROTEROZOIC EONFrom 3800 to 2500MesoproterozoicEra CalymmianPeriod)-Oxygenbuildsup intheatmosphere.-Formationof ozonelayer.- Eukaryotic(nucleated)cellsappear.EctasianPeriod- lots of green (Chlorobionta) and red (Rhodophyta)algae.StenianPeriod- Spore-gameteformation sexualreproduction.- Formationofthesupercontinent.



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