Introduction to the Proterozoic Era ... With the beginning of the Middle Proterozoic comes the first evidence of oxygen build-up in the atmosphere. This global catastrophe spelled doom for many bacterial groups, but made possible the explosion of eukaryotic forms.
www.ucmp.berkeley.edu/precambrian/proterozoic.html www.ucmp.berkeley.edu/precambrian/proterozoic.html
Proterozoic - Wikipedia, the free encyclopedia
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The Proterozoic (pronounced /ˌproʊt ə rəˈzoʊ ɪ k/ ) is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "ea...
en.wikipedia.org/wiki/Proterozoic
Geologic time scale - Wikipedia, the free encyclopedia
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The geologic time scale is a chronologic schema (or idealized model) relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and r...
en.wikipedia.org/wiki/Geologic_time_scale
Timeline of evolution - Wikipedia, the free encyclopedia
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This timeline of the evolution of life outlines the major events in the development of life on the planet Earth (See Organism). For a thorough explanatory context, see the history of Earth, and geol...
en.wikipedia.org/wiki/Timeline_of_evolution
Palæos: Proterozoic The Proterozoic Eon ... PROTEROZOIC EON Proterozoic 1 ... The Proterozoic Eon of Precambrian Time: 2500 to 542 million years ago...
www.palaeos.com/Proterozoic/Proterozoic.htm www.palaeos.com/Proterozoic/Proterozoic.htm
Brief and Straightforward Guide: What is the Proterozoic Eon? ... The Proterozoic Eon is one of four eons of time making up the history of this planet. It is the third of four eons, the first two with little preserved life, the last two with it. The eons include the Hadean, the Archean, the Proterozoic, and the Phanerozoic.
www.wisegeek.com/what-is-the-proterozoic-eon.htm www.wisegeek.com/what-is-the-proterozoic-eon.htm
Proterozoic Time ... During the Proterozoic time, the area that was to become the Ozarks became a part of the future North American continent. The oldest rocks in Missouri are of mid- Proterozoic age, 1.6 to 1.8 billion years old. ... Earth Geology Geologic Time Scale Proterozoic Eon;
www.watersheds.org/earth/gtime01c.htm
North America in the Archean eon ... In the late Archean eon, the plates of Earth's crust may have continued to move at a relatively high speed. Evidence of these wild times can be found in the ancient core of North America. The scars of tectonic events appear as rock outcrops throughout the part of northern North...
science.jrank.org/pages/4716/North-America.html
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Proterozoic Eon for Kids - the first multicellular creatures ... By 2.5 billion years ago, when the Archaean Eon ended and the Proterozoic Eon began, trillions of prokaryote cells lived in Earth's oceans. Some of these cells could photosynthesize their energy from sunlight, water, and carbon dioxide.
www.historyforkids.org/scienceforkids/geology/eras/prot... www.historyforkids.org/scienceforkids/geology/eras/proterozoic.htm