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HOW LIFE HAS AFFECTED THE EARTH?

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Last updated over 1 year ago
17 questions
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Question 4
4.

Wait, how do we know how much oxygen was present before humans existed?

Because scientists have analyzed oxygen isotopes from gases trapped in __________.

Question 5
5.

What do you already know about EARLY EARTH'S ATMOSPHERE?

Question 6
6.

Predict how oxygen amounts have changed over time on Earth.
What would the line graph look like?

Question 7
7.

What is Table 1 data showing?

USING Table 1 data, on a separate graph paper, set up and graph "How OXYGEN Has Changed Over Time on Earth".

Hint: You can copy how to set it up.
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Now add the 10 GEOLOGIC EVENTS from Table 2 to the correct spots on your graph paper.
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Question 1
1.

The first bacteria on Earth _____ use oxygen.

Question 2
2.

Photosynthesis (by cyanobacteria and plants) ______ oxygen gas.

Question 3
3.

2 ways scientists think Earth started to get more oxygen in the air is by:

Question 8
8.

Does your graph on your paper look like anything you predicted in #6?

Question 9
9.

What is Table 2 data showing?

Question 10
10.

Look at the data table 1 again.

Which gas has made up the LARGEST portion of the Earth's atmosphere for most of Earth's history?

Question 11
11.

Which gas did not appear until about 2 billion years ago?

Question 12
12.

Which gas has been almost nonexistent since about 3 billion years ago?

Question 13
13.

When limestone deposits became common, which gas appeared in the atmosphere?

Question 14
14.

Look at your graph paper.

Which event from the 10 you copied is correlated with (related to) the increase in oxygen (and the decrease in CO2)? WHY?

Question 15
15.

Look at your paper graph.

How would you describe the TREND of oxygen levels throughout Earth's history?

Question 16
16.

If cyanobacteria started doing photosynthesis 3bya, how come it took 1 billion years to start seeing oxygen in the air?

Question 17
17.

If Venus and Mars' atmospheres have mostly CO2 and Earth's atmosphere is mostly N and O...

WHY do you think our atmosphere is so different?