a generalized history of earth
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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 - - - - - - -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
Accumulation of the Iron Formations
2.5 billion years - - - - - 1.7 billion years
Some critical level of oxygen
ppt of iron oxides
Seas lose their Fe
Generalized reaction Not ballanced or proper oxidation
states
Fein solution + O2 FeO.nH2O ppt
Sexual reproduction!!!!! 1.7 billion years - - - - - 540 million years
Eukaryotic cells! Life forms go nuts Seas and
atmosphere approach modern compositions
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-tenidffeetenidffee
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 KeyKey to fossilization Hence, key to information
preservation
Shells of various sorts
Fish have bone and teeth
245 million years - - - - - 66 million years
Great extinction Plate movements 1 Cone bearing
plants Dinosaurs Mammals Plate movements 2 Birds Flowering plants
A GREAT EXTINCTION AT245 MILLION YEARS
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
PLATE CONFIGERATION ATABOUT 180 MILLION
YEARS
Some new players in the game of life
PLATE CONFIGERATION AT ABOUT 120 MILLION
YEARS
66 million years - - - - - 1.6 million years
Extinction Earliest horse Grasses Earliest hominids
A MAJOR EXTINCTION AT66 MILLION YEARS
BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY BIO FAMILY
DINOSAURS
Three new players in the game of life
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
AND CAME THE ICE AND COVERED ~25% OF THE
LAND
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