the evolution of the atmosphere

Question 1

today, around what percentage of the atmosphere is nitrogen?

Answer 1

around 78%

Question 2

today, around what percentage of the atmosphere is oxygen?

Answer 2

around 21%

Question 3

today, what other gases are there small proportions of?

Answer 3

water vapour, carbon dioxide and noble gases such as argon

Question 4

how long have gases remained how they are now?

Answer 4

200 million years

Question 5

the earth is 4.6 billion years old, what does this mean for scientists?

Answer 5

scientists cant be sure about early atmosphere

Question 6

during the first billion years, what type of activity was there lots of?

Answer 6

intense volcanic activity

Question 7

what 5 gases did volcanoes release?

Answer 7

nitrogen, water vapour, carbon dioxide, methane and ammonia

Question 8

as the earth cooled, what did water vapour from volcanoes condense to form?

Answer 8

oceans

Question 9

in the early stage of earth, earths atmosphere consisted mainly of _____ ____ with little to no _____?

Answer 9

in the early stage of earth, earths atmosphere consisted mainly of carbon dioxide with little to no oxygen

Question 10

in the early stage of the earth, what 2 planets were earth’s atmosphere similar to?

Answer 10

mars and venus

Question 11

volcanoes released _____, which built up over time?

Answer 11

volcanoes released nitrogen, which built up over time

Question 12

some of the carbon dioxide from the volcanoes dissolved into oceans to form a ____ ____?

Answer 12

some of the carbon dioxide form the volcanoes dissolved into oceans to form a weak acid

Question 13

the carbon dioxide in the ocean reacted with sea minerals to form precipitates, which formed sediments of ______ ___ on the ___ ___?

Answer 13

the carbon dioxide in the ocean reacted with sea minerals to form precipitates, which formed sediments of carbonate rocks on the sea bed

Question 14

some of the carbon dioxide in sea was used to make ___ and __?

Answer 14

some of the carbon dioxide in sea was used to make corals and mussels

Question 15

when corals and mussels died, what did they form?

Answer 15

a sedimentary rock called limestone

Question 16

limestone removed ______ _____ from the atmosphere?

Answer 16

limestone removed carbon dioxide from the atmosphere

Question 17

2.7 billion years ago, ________ ___ first evolved in oceans?

Answer 17

2.7 billion years ago, photosynthetic algae first evolved in oceans

Question 18

photosynthetic algae did photosynthesis, which produced _____ into the atmosphere?

Answer 18

photosynthetic algae did photosynthesis, which produced oxygen in the atmosphere

Question 19

as oxygen levels built up in the atmosphere, it reached the point where _____ evolved?

Answer 19

as oxygen levels built up in the atmosphere, it reached the point where animals evolved