Self-Check: The Atmosphere and Life on Earth
Check your understanding of the atmosphere’s effect on life on Earth by answering each question below. Answer the questions for yourself and then click to see the answer.
We often say that Earth has the "just right" amount of oxygen. Why is this so?
If Earth had any less oxygen, the planet could not support animal metabolism, since oxygen is an essential component of the red blood cells, and necessary for metabolic functioning. If Earth had just five percent more oxygen, then combustion would take place too easily and organic materials would burn.
As you will learn later in this unit, ozone at the ground-level is considered an undesirable pollutant. However, in the upper atmosphere, ozone is necessary for life on Earth. Why is atmospheric ozone not a pollutant?
Atmospheric ozone protects Earth from excessive levels of harmful UV radiation.
Which gases contribute most to Earth’s greenhouse effect? How does human activity impact the levels of those gases?
Carbon dioxide and methane are two greenhouse gases, both of which are elevated in the atmosphere by burning fossil fuels, by agriculture, and deforestation.
