Earth's Atmosphere is made mostly of what elements?
Nitrogen, Oxygen, and Argon
Terrestrial planets' atmospheres are mostly made of what elements?
Carbon dioxide and Nitrogen
Jovian planets' atmosphere are mostly made of what elements?
Hydrogen and Helium
What was the time interval of Earth's first atmosphere?
4.6-4 billion years ago
What was the time interval of Earth's second atmosphere?
4-3.3 billion years ago
What was the time interval of Earth's third atmosphere?
3.3-.4 billion years ago
What was the time interval of Earth's fourth atmosphere?
.4-present billion years ago
Earth's primitive atmosphere consisted of what elements?
Mainly H2 and He, minor amounts of NH3 and CH4
Earth's primitive atmosphere is similar to what other atmosphere?
the atmosphere of Jovian planets
How was NH3 and CH4 disassociated from the atmosphere during the primitive stage?
heat and UV radiation
What happened to H2 and He after NH3 and CH4 became disassociated during the primitive stage?
H2 and He escaped into space
What happened after H2 and He escaped during the primitive stage?
N became enriched
What did Earth's second atmosphere mainly consist of?
CO2, H2O, N, SO2 and high vapor pressure
What had a large impact on Earth's second atmosphere?
volcanic outgassing and impact degassing
When did oceans form?
During Earth's second atmosphere
How and when did oceans form?
by the cooling and condensing of water vapor approximately 3.9-3.9 billion years ago
What are two formations that occurred during the formations of oceans and how did they form?
pillow basalt: formed because of lava extrusions underwater. Marine sediments: fine-grained sediment that has accumulated by the settling of particles through the water column to the ocean floor beneath the open ocean far from land
Did anaerobic life still exist in the deep ocean even though there was no UV radiation filtering?
What still remained during the Earth's second atmosphere?
anoxic atmospheric conditions
What increased and decreased during the Earth's third atmosphere?
increasing O2 and decreasing CO2
What formed limestone in the ocean, and when?
During the Earth's second atmosphere, precipitation of calcite in ocean and absorption of CO2
What occurred during Earth's third atmosphere due to an increase in O2 and a decrease in CO2?
photo-dissociation and photosynthesis
What is photo-dissociation?
a chemical reaction in which a chemical compound is broken down by photons
What were the elements in the Fourth atmosphere?
Mainly N, O2, and Ar
What did photosynthesis produce during Earth's third atmosphere?
What is the evidence of early life forms in the ocean during Earth's third atmosphere?
stromatolites, fossil cyanobacteria, and banded-iron formations
Why are banded-iron formations relevant?
the result of oxygen released by photosynthetic cyanobacteria (bluegreen algae), combining with dissolved iron in Earth's oceans to form insoluble iron oxides, which precipitated out, forming a thin layer on the substrate, which may have been anoxic mud (forming shale and chert).
What are Eukaryotic bacteria?
oxygen mediating enzymes
What did the ozone layer make possible?
surface layer marine life, respiratory metazoans, and land plants possible
When did oxygen saturate the mantle and crust?
1 billion years ago
Where on Earth did life most likely originate?
When did marine plants advance to multicellular plants?
.8 billion years ago
When did the ozone layer develop?
During Earth's third atmosphere
How did the ozone originate?
Ozone in the Earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O2), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O2 to create ozone, O3.
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