Section B Flashcards
(29 cards)
What does the term biosphere mean?
The “living globe.
Is a thin layer around the earth that supports life.
What are the three layers of the biosphere?
Atmosphere
Lithosphere
Hydrosphere
What is the atmosphere?
All of the gases surrounding the Earth.
How thick is the atmosphere?
500 km thick
What is the composition of gases in the atmosphere?
78% nitrogen and 21% oxygen.
Why is nitrogen important?
Needed for plant growth
Why is oxygen important?
Needed by organisms and maintained by photosynthesis
What else does the atmosphere contain besides gases?
Atmospheric dust (e.g., soot, pollen).
What essential function does the atmosphere perform related to harmful rays from the sun?
It filters out most lethal radiation.
How much of the sun’s energy is absorbed by the atmosphere?
20%.
What are the main gases in the atmosphere and their approximate percentages?
78%, Oxygen – 21%, Other (CO₂, etc.) – 0.97%.
How many layers are there in the atmosphere?
4 layers
What are the characteristics of the atmospheric layer from 0–10 km in altitude?
Average temperature: 15°C to 60°C, contains 80% of gases, supports most life, weather occurs in this layer.
What atmospheric layer contains the ozone layer and absorbs UV radiation?
The layer from 10–50 km (stratosphere).
What is ozone (O₃), and where is it found?
It is an inorganic molecule found in the stratosphere
- What type of radiation does ozone absorb from the sun?
UV radiation.
What is the ozone hole
A region in the ozone layer that has thinned.
Where have ozone holes been identified?
Over Antarctica and the Canadian Arctic
What can increased UV radiation at the ground level cause?
Crop surface damage and increased cases of skin cancer
What are two reasons for ozone layer depletion?
Reaction of ozone with chlorofluorocarbons (CFCs).
Natural cycles in the atmosphere.
What is the lithosphere?
All land on Earth from surface to 100 km below.
Where does the lithosphere run?
Under the continents and oceans.
What warms the lithosphere?
The sun and molten material in the Earth’s mantle
What does the hydrosphere include
All water on Earth.
