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