BC: The End
FC: Islam Mekky 7-4 2-27-2013
1: topic: Proterozoic table contents introduction 2 plants 4 animals 6 climate 8 summary 10 bibliography 11 the end 12
2: INTRODUCTION The Proterozoic was the fourth of the eons of earth history, lasting some two gig years, almost half the age of the earth. The Proterozoic is the time when more or less modern plate tectonics began to govern over other process in determining the form of earth's crust. Everything is happening faster. The magma, on which the continents floated on, is hotter, less viscous, and closet to the surface. Life developed from the infant stage of single celled organisms to an adolescence of eukaryote and early plants, fungi, and animals.
4: PLANTS One of the most important events of the Proterozoic was the gathering up oxygen in earth's atmosphere. Oxygen was undoubtedly released by photosynthesis well back in Archean time's rimbesella is often compared to mollusks. Cynobacteria produced oxygen through the process of photosynthesis. Cynobacteria used sunlight, food, and water by the process of photosynthesis by getting the food needed.
6: ANIMALS Animals The first advanced single-celled, eukaryotes and multi-cellular life, Trancevillian Group Fossils, roughly coincides with the start of the accumulation of free oxygen. Also the fossils found in Proterozoic Eon. This way has been due to an increase in the oxidized nitrates that eukaryotes use, as opposed to cynobacteria and as during the Proterozoic that the first symbiotic relationships between mitochondria (for nearly all eukaryotes) and chloroplast (for plants and some protists only) and their host evolved. The blossoming of eukaryotes such as asitarchs did not preclude the expansion of cynobacteria; in fact, stromatobites reached their greatest abundance and diversity during the Proterozoic, peaking roughly 1200 million years ago.
7: The boundary between Proterozoic and the Phanerozoic eons was set at the base of the Cambrian period when the first fossils of animals including trilobites and archeocyathicly appeared. Eukaryotes are concluded the start of free oxygen. As years passed fossils of animals and life were found in Proterozoic Eon
8: CLIMATE At the end of the Proterozoic the planet was hit with an Ice Age so hard that many scientists believe most of the Earth was covered in glaciers. This period was called the Cryogenian for its low temperatures. Glaciers extended and contracted in a series of rhythmic pulses, possibly reaching so far as the equator. It is generally considered to be divisible into at least two major worldwide glaciers. The Sturtian glaciations persisted from 750 million years ago to 700 Ma, and the Marinoan glaciations which ended approximately 635 Ma. The deposits of the glacial tillite also occur in places that were at the low attitudes during the Cryogenian, a phenomenon which led to the hypothesis of deeply frozen planetary oceans called “Snowball Earth”.
9: The climate was cold at the end of the Proterozoic causing the Ice Age because of its tectonics. At the beginning of the Proterozoic Eon maybe it was warm.
10: SUMMARY The Proterozoic Eon means “earlier life”. It lasted for almost half the age of the Earth. Proterozoic is an Eon divided into Eras. Fossils identified earlier animals that lived at that time. There were single-celled eukaryotes and there are many-celled that had been specialized by scientists. The first fossils were discovered in the period of Proterozoic Eon. Plants didn't really exist, but there was chloroplasts which used light to convert it into energy by organisms.
11: Bibliography | 1.MAK. "Palaeos Proterozoic: The Proterozoic Era." Palaeos: Life Through Deep Time. N.p., 12 Nov. 2003. Web. 10 Apr. 2013.