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Published byMarcus Baldwin Modified over 9 years ago
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Overview of natural history
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Breakdown of time Different periods of Earth’s history are broken into sets of time –just like a year is broken into months, weeks, days and hours Earth history is broken into eons, eras, periods, epochs
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Eons – Millions and Billions of years Haden: Earth before life evolved 4.6 to 3.5 Billion years ago (13% of Earth’s history) Achaean: Earth with only bacteria like cells 3.5 to 2.5 Billion years ago (28% of Earth’s history) Proterozoic: Multicellular life forms 2.5 BYA to 540 MYA (48% of Earth’s history) Phanerozoic: Dinosaurs to now 540 MYA – present day (11% of Earth’s history)
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How time periods are distinguished Major geological events: The movement of tectonic plates to form continents & super- continents Changes in climate: a change from an ice ace to a warming period Mass extinctions or explosions: Changes in the types of life forms on earth
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Haden Eon 4.6-3.5 BYA So hot that the rock was molten & Water was vapor Lifeless, little O 2 in the atmosphere Relative to a calendar year: Jan 1 st – Feb. 25 th
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Achaean Eon 3.5-2.5 BYA Earth cooled enough to have a crust & ocean Life forms in the sea Bacteria & photosynthetic blue-green algae Feb. 25 th - April 17 th
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Proterozoic Eon: Precambrian Era 2.5 BYA – 540 MYA Super continent Rodinia 21% O 2 in Atmosphere First complex cell -July 13 th First multicellular organism (seaweed/algae) –Aug 31 st
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Haden lifeless Earth Achaean Prokaryotic life Little O 2 Review of Earth’s first 3.9 Billion years Proterozoic Eukaryotic life, multicellular plants, First plants & soft bodied animals in oceans later vascular plants fish, arthropods in ocean Insects, amphibians & reptiles on land
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Paleozoic Era From the Cambrian explosion to the dawn of the dinosaurs
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Cambrian - Permian period:540 MYA – 248 MYA Cambrian: Starts with a burst of new life forms & all life in ocean Plants & animals evolved from simple seaweed & sponges to fish in the oceans & insects, amphibians, and early reptiles on land 1 Mass extinction in the ocean Nov. 17 – Dec 6
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Triassic period to Holocene Epoch 248 MYA – present From the early dinosaurs to extinction 65 MYA 1 st mammals, birds, and flowering plants The ice age to modern civilization Dec 7 th - Midnight Dec 31 st
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Review of last 248 Million years First Dinosaurs Last Dinosaurs Flowering Plants First Mammals First bird First monkey First human
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Review 1.What was the surface of the earth like during the Haden Era? 2.During which era did multicellular life evolve? 3.Which is a shorter period of time and eon or an era? 4.Which came first birds or mammals?
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