C1.1 The Earths Sea And Atmosphere

Question 1

Which gas is most likely to have made up a large part of the earths early atmosphere?

Answer 1

Nitrogen

Or Carbon Dioxide

Question 2

What released these gases into the atmosphere?

Answer 2

Volcanoes

Question 3

Where is evidence that there was an absence of oxygen in the earths early atmosphere?

Answer 3

The iron compounds found in the oldest rocks only form in the absence of oxygen.

Question 4

What happened as the earth became older, and how did it affect the gases?

Answer 4

It cooled down over time, and so the water vapour in the atmosphere became the oceans.

Question 5

What happened when seas appeared?

Answer 5

A lot of the carbon dioxide dissolved into the sea, allowing marine animals to develop. They became buried when they died to form sedimentary rocks.

Question 6

What was the effect of plants on the atmosphere?

Answer 6

They removed atmosphere from the atmosphere and gave out oxygen through photosynthesis. This increased the oxygen levels and allowed more complex organisms to flourish.

Question 7

What does the Ozone layer do?

Answer 7

It blocks the harmful rays from the sun to allow even more complex organisms, like us, to develop.

Question 8

What are three main factors that contribute to the atmosphere changing today?

Answer 8

1. Burning fossil fuels
2. Deforestation
3. Livestock farming

Question 9

What two gases do volcanoes release and how do they effect the atmosphere?

Answer 9

1. Sulphur dioxide- It reacts with sunlight, water, oxygen and dust to form volcanic smog.
2. Carbon dioxide- It contributes to global warming.

Question 10

What is our main source of information about the early atomsphere?

Answer 10

Antarctic Ice cores.