Eveloution Of The Early Atmosphere

Question 1

What is the atmosphere made up of today

Answer 1

80% nitrogen
20% oxygen
<1% other gases

Question 2

What was the atmosphere like in the first billions of years

Answer 2

Really dry
Intense volcanic activity
Loads of co2, water vapour and nitrogen
Smaller amounts of methane and ammonia

Question 3

In the first billions of years what did the atmosphere mainly consist of

Answer 3

Co2

Question 4

What happened to the water vapour from the first billions of years

Answer 4

It condensed to form the oceans

Question 5

What happened to the co2 from the early atmosphere

Answer 5

It dissolved in the oceans
Formed precipitates
Then sediments (sea bed)

Question 6

What started to happen 2.7 billion years ago

Answer 6

Alge began to appear
Green plants evolved

Question 7

Why did the amount of CO2 reduce in the atmosphere

Answer 7

As green plants evolved
More photosynthesis was occurring
Taking in carbon and releasing oxygen

Question 8

What did the increase in oxygen levels allow to happen

Answer 8

Allowed animals to evolve

Question 9

What happened why the plants died and fell into the oceans

Answer 9

Fell to the seabed
Formed sedimentary rock, oil and gas
This trapped the carbon

Question 10

What does crude oil and natural gas form from

Answer 10

Dead plankton

Question 11

What does coal from from

Answer 11

Type of sedimentary rock formed from thick deposits of dead plant material

Question 12

What does limestone form from

Answer 12

Type of sedimentary rock Made from the calcium carbonate incorporated into sea creatures shells and skeletons