evolution of the atmosphere

Question 1

what was the earths surface like in its first billion years

Answer 1

It was covered in volcanoes that erupted and released gases.

Question 2

what gases made up the early atmosphere

Answer 2

Mostly carbon dioxide with little or no oxygen. Volcanoes also released nitrogen, water vapor, methane, and ammonia

Question 3

how did the oceans form

Answer 3

The water vapor in the early atmosphere condensed into liquid water, forming oceans.

Question 4

how was carbon dioxide removed from the atmosphere

Answer 4

• It dissolved in oceans and formed carbonate sediments.
• It was absorbed by plants and algae during photosynthesis.
• It was trapped in fossil fuels and sedimentary rocks.

Question 5

how did fossil fuels form

Answer 5

• Coal, crude oil, and natural gas formed from dead sea organisms that were buried and compressed over millions of years.
• Limestone formed from calcium carbonate shells and skeletons of marine organisms.

Question 6

when did algae evolve and why was it inportant

Answer 6

Algae evolved 2.7 billion years ago, followed by green plants. They released oxygen through photosynthesis.

Question 7

what is the word equation for photosynthesis

Answer 7

Carbon dioxide + water → glucose + oxygen

Question 8

why was the increase in oxygen levels significant

Answer 8

It allowed animals to evolve as they required oxygen for respiration.

Question 9

what are the current % of gases in the atmosphere

Answer 9

• 80% nitrogen
• 20% oxygen
• Small amounts of carbon dioxide, noble gases, and water vapor