Geologic Time By kcaperton Period: Jan 1, 2015 to Nov 17, 2015 Precambrian Time Feb 9, 2015 First crustal rocks form Precambrian Time Mar 30, 2015 Earths surface is cool enough for liquid water Apr 12, 2015 First known unicellular life appears Jul 14, 2015 Earths atmosphere starts to become oxygen rich Aug 31, 2015 First known multicellar life appears Sep 29, 2015 First fungi appear Nov 15, 2015 First shelled organisms, such as arthopods and mollusks, appear. Period: Nov 17, 2015 to Dec 10, 2015 Paleozoic Time Nov 19, 2015 First possible vertabrates appear Nov 21, 2015 Modern, oxygen-rich atmosphere has formed. Nov 24, 2015 First land appears Nov 28, 2015 First anthropods appear on land Nov 30, 2015 First amphibians appear Dec 2, 2015 First reptiles appear Dec 5, 2015 Formation of pangea is complete Dec 9, 2015 Permian mass extinction results from major enviromental changes Period: Dec 10, 2015 to Dec 25, 2015 Mesozoic Time Dec 11, 2015 Pangea begins to break apart Dec 13, 2015 First mammals appear Dec 16, 2015 First primitive birds appear Dec 19, 2015 First flowering plants (angiosperms) appear Dec 21, 2015 First modern birds appear Dec 25, 2015 The last dinosaurs become extinct. Catastarphic merteorite impct occurs. Dec 25, 2015 Modern mammal famlilies, including whales, carnivores, hoofed animals, and primates have apeared. Period: Dec 25, 2015 to Dec 31, 2015 Cenozoic Time Dec 26, 2015 First grasses appear Dec 27, 2015 India collides with asai and antartica drifts over the south pole Dec 28, 2015 First hominids (early human ancestors appear) Dec 29, 2015 Modern ice age begins Dec 31, 2015 Modern humans appear
