Early Atmosphere - Planets

Question 1

What is Earth’s early atmosphere predicted to have been and why?

Answer 1

(mostly) carbon dioxide

Both Venus and Mars are rocky planets with a magma interior, like Earth
Both Venus and Mars have a carbon dioxide atmosphere due to volcanic activity

Early Earth had high levels of volcanic activity
We can assume that Earth also had high levels of carbon dioxide and water vapour from eruptions

Question 2

What type of planet is Earth?

Answer 2

rocky planet

Question 3

What type of interior does Earth have?

Answer 3

magma

Question 4

What type of planets/moons are:

1) Venus
2) Mars
3) Titan (Saturn’s moon)

Answer 4

1) Rocky
2) Rocky
3) Ice

Question 5

What type of interiors do these planets/moons have:

1) Venus
2) Mars
3) Titan (Saturn’s moon)

Answer 5

1) magma
2) magma
3) ice

Question 6

What is the current atmosphere of these planets:

1) Venus
2) Mars
3) Titan (Saturn’s moon)

Answer 6

1) carbon dioxide
2) carbon dioxide
3) nitrogen

Question 7

Why can’t Earth be compared to Titan/why wasn’t the main atmospheric gas nitrogen?

Answer 7

Titan is an ice moon with an ice interior, while Earth is a rocky planet with a magma interior.

This means that their atmospheres are likely different.

Question 8

What caused the change in nitrogen concentration in the atmosphere?

Answer 8

(ammonia makes nitrogen if reacted with oxygen/ nitrogen is unreactive)

as more oxygen was released into the atmosphere it reacted with ammonia to make nitrogen

the nitrogen didn’t react with anything so the levels kept increasing

Question 9

State how cooling changed the composition of the Earths atmosphere.

Answer 9

cooling caused water vapour in the atmosphere to condense and form oceans

Question 10

Explain how photosynthesis changed the composition of the Earth’s atmosphere.

Answer 10

photosynthesis uses carbon dioxide and water to make oxygen and glucose

the level of carbon dioxide decreased and oxygen levels increased

Question 11

Explain what has caused the percentage of carbon dioxide to decrease.

Answer 11

-The oceans absorb/dissolve carbon dioxide

• Plants use carbon dioxide for photosynthesising
• The number of plants kept increasing

-Early sea creatures formed shells using carbon dioxide/calcium carbonate, allowing the oceans to absorb more carbon dioxide

Question 12

What is the formula for calcium carbonate?

Answer 12

CaCO₃

Question 13

Give the name of some of the earliest photosynthetic microorganisms

Answer 13

cyanobacteria/blue green algae