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A GENERALIZED HISTORY OF EARTH. TIMES. This can be done several ways I choose to break Earth’s history into nine time periods. ~~5 billion years - - - - - 4.6 billion years. Extrapolation for the most part Formation of solar system—accumulation of space trash. 4.6 billion years - -
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TIMES • This can be done several ways • I choose to break Earth’s history into nine time periods
~~5 billion years - - - - - 4.6 billion years Extrapolation for the most part Formation of solar system—accumulation of space trash
4.6 billion years - - - - - - -3.8 billion years Heating and melting of earth Out-gassing; early atmosphere Segregation of and cooling of entire Earth Early crust Early seas Beginnin of Plate Tectonics Life—single cell, anaerobic, prokaryotic, bacteria
3.8 billion years - - - - - 2.5 billion years Seas, freshsalty Life – earliest plants, prokaryotic, photosynthesis Atmosphere, more O, less CO2
Photosynthesis (within plant cell) • Energy (radiant) • CO2 C(in tissues) + O2
2.5 billion years - - - - - 1.7 billion years Some critical level of oxygen ppt of iron oxides Seas lose their Fe Accumulation of the Iron Formations
Generalized reaction • Not ballanced or proper oxidation states • Fein solution + O2 FeO.nH2O ppt
1.7 billion years - - - - - 540 million years Eukaryotic cells! Life forms go nuts Seas and atmosphere approach modern compositions Sexual reproduction!!!!!
Importance of sexual vs. asexual reproduction • Asexual (prokaryotic life) like a clone – like-like-like-like-like-like-like • Sexual (eukaryotic life) exchange and mixing of genes – great variability unlike-ikulen-different-efefident-tenidffee
540 million years - - - - - - 245 million years Hard parts!! Plate movements Fish Land plants Amphibians Seed ferns and scale trees reptiles
Hard parts • Shell – CaCO3 • Kytton – complex, organic, C-bearing • Bone – CaPO4 • Teeth – CaPO4 • Scales -- • Cellulose (sort of) – complex, organic, C-bearing
Hard parts -- importance • Protection and structure • Key to fossilization • Hence, key to information preservation
245 million years - - - - - 66 million years Great extinction Plate movements 1 Cone bearing plants Dinosaurs Mammals Plate movements 2 Birds Flowering plants
BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY marine invertebrates marine invertebrates marine invertebrates marine invertebrates marine invertebrates marine invertebrates marine invertebrates marine invertebrates marine invertebrates marine invertebrates A GREAT EXTINCTION AT245 MILLION YEARS
66 million years - - - - - 1.6 million years Extinction Earliest horse Grasses Earliest hominids
BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY DINOSAURS A MAJOR EXTINCTION AT66 MILLION YEARS
1.6 million years - - - - 1,200 years NOW The ice ages
The Ice Ages • A time of climatic vairation • Four times cold • Four times ice caps and glaciers • Spaced by warm (like now) • Including warm before and now