BC: THE END
FC: Layal Gharib section: 7-3 date:
1: My topic is the Proterozoic Era. TABLE CONTENTS: Proterozoic Era pages: Time: 1 what was occurring: 2 plants: 3 animals: 4 climate: 5 summary: 6 bibliography: 7 the end: 8
2: the Proterozoic era started 25 billion years ago.
4: when the Archean eon ended and the Proterozoic eon began, trillions of Prokaryote cells lived in the earths oceans. some of these cells could photosynthesize their energy from sunlight, water, and carbon dioxide.
6: PLANTS: Although early fossils are now thought to occur in older Archean rocks for many years. the oldest evidence of life was known from the Proterozoic strata. the Proterozoic represents the last stage of what was one called the Precambrian the 3.7 billion year long period before the Paleozoic Era.
8: ANIMALS The first traces in life happened nearly 3.5 billion years ago, in the early Archean. fossils have been identified from the era until the late Archean when Stromatolites layered mounds (a collection of objects laid on top of each other), that are produced by the growth of microbial mats, they become common in the rock record.
10: climate The end of the Proterozoic saw at least 2 snowball Earths, so severe that the surface of the oceans may have been completely frozen. this happened about 710 and 640 MA. in the Cryogen ion period. these severe glaciations are less easy to explain than the early Proterozoic snow ball Earths.
12: Summary: what i understood from my topic is that the word Proterozoic came from a Greek word. Proteros (first) and zoon (life). the climate at the end of the Proterozoic saw at least 2 snowball earths that were so severe that the surface of the oceans may have been completely frozen. the first traces of life appeared nearly 3.5 billion years ago in the early Archean.
13: Bibliography | "Proterozoic Eon - Science for Kids!." Kidipede - Science for Kids - Homework Help for Middle School. N.p., n.d. Web. 10 Apr. 2013.