atmospheres

Question 1

when was the first atmosphere?

Answer 1

3.5 - 4.5 billion years ago

Question 2

how did the first atmosphere develop?

Answer 2

outgassing or the release of gases from volcanoes to the atmosphere (gases such as CO2, H2O, H2S, N2, CH4, and CO)

Question 3

what organisms thrived during the time period of the first atmosphere?

Answer 3

anaerobic organisms thrived during this time as they did not rely on oxygen to survive

Question 4

how did the first atmosphere transform?

Answer 4

“giant impact hypothesis” - the theory that a celestial body collided with the earth, displacing a huge volume of atmospheric material; this later transformed the moon + destroyed earth’s atmosphere

Question 5

when was the second atmosphere?

Answer 5

2 - 3.5 billion years ago

Question 6

how did the second atmosphere develop?

Answer 6

developed when a huge volume of gas (gases such as H2O, CO2, and N2) and steam were released from the earth’s surface by volcanic activity

Question 7

how did oceans developed as a result of the release of gas and steam during the second atmosphere?

Answer 7

as earth cooled, the steam condensed into liquid water forming the oceans through precipitation

Question 8

what organisms were prevalent during the second atmosphere?

Answer 8

cyanobacteria thrived in the oceans which used sunlight to combine carbon dioxide and water into sugar and oxygen (photosynthesis), leading to no free oxygen available during this time period

Question 9

how did the excess of free oxygen from the second atmosphere lead to the development of the third atmosphere?

Answer 9

cyanobacteria thrived, causing the excess of oxygen - led to mass extinction of anaerobic species which then led to the third atmosphere