The Four Conditions for LifeName______
Global Geography
Page 44 – 48
Answer the following questions in point form (for your notes – not to pass in).
Why can’t the other planets in the solar system support life?
List the four conditions that allow life to exist on Earth.
Why is the distance of Earth from the sun important?
What does the rotation of the Earth do?
What does Earth’s gravity do?
What does the Earth’s magnetic field do?
What is the range of temperature on Earth (lowest to highest)?
What is the range of Earth’s average temperatures?
How does Earth’s atmosphere act like a greenhouse?
What would happen if there wasn’t enough water(H2O) or carbon dioxide (CO2) in the atmosphere?
What are two reasons plants are important?
What is albedo?
What fraction of the Earth is covered by water?
In what three ways is water needed for the Earth to function?
List three reasons why water is essential to living things.
What gas makes up most of the atmosphere on Venus and Mars?
How is the atmosphere on Earth different?
How did the atmosphere change when plant life began to grow?
List three ways the atmosphere helps to protect the living things on Earth.
The Four Conditions for LifeName______
Global Geography
Page 44 – 48
Answer the following questions in point form (for your notes – not to pass in).
Why can’t the other planets in the solar system support life?
They are too hot or too cold, have high levels of radiation, no water or no atmosphere
List the four conditions that allow life to exist on Earth.
- mild temperatures
- lots of water
- atmosphere that supports life
- radiation from the sun is blocked by the atmosphere
Why is the distance of Earth from the sun important?
- we are just the right distance to give us a mild average temperature
What does the rotation of the Earth do?
- it allows the heat of the sun to spread out over the planet from day to night (otherwise one side would be always hot and the other cold)
What does Earth’s gravity do?
- keeps the atmosphere’s gases from escaping into space
What does the Earth’s magnetic field do?
- prevents particles and radiation from the sun from entering the atmosphere
What is the range of temperature on Earth (lowest to highest)?
- -50ºC to +50ºC
What is the range of Earth’s average temperatures?
- 10ºC to 20ºC
How does Earth’s atmosphere act like a greenhouse?
- it lets in light but traps heat
- the light is changed into heat when it reaches the surface, so the Earth and atmosphere get warm near the surface
What would happen if there wasn’t enough water(H2O) or carbon dioxide (CO2) in the atmosphere?
- these gases control the greenhouse effect
- without them, the temperatures around the world would drop
What are two reasons plants are important?
- plants control water and CO2
- provide areas of dark surface which absorb the sunlight and turn it into heat (both things balance thetemperature)
What is albedo?
- is a measure of how much light is reflected (high albedo means white surfaces, like snow and low albedo means dark surfaces like forests)
What fraction of the Earth is covered by water?
- two thirds
In what three ways is water needed for the Earth to function?
- absorbs heat and moves it around
- provides the water that is needed in the atmosphere
- dissolves nutrients and moves them around
List three reasons why water is essential to living things.
- makes up a large part of their bodies
- circulates nutrients and gases in the body
- is the liquid in which chemical reactions of life occur
What gas makes up most of the atmosphere on Venus and Mars?
- almost entirely carbon dioxide (CO2)
How is the atmosphere on Earth different?
- mainly nitrogen (78% N2) followed by oxygen (21% O2) and only small amounts of other gases
How did the atmosphere change when plant life began to grow?
- removed carbon dioxide (CO2) and produced oxygen (O2)
List three ways the atmosphere helps to protect the living things on Earth.
- maintains even temperatures; shields earth from meteors and particles; and protects the surface from radiation