Biosphere Basics
The biosphere is the living skin of the planet. Trace the great biomes from the equator to the poles, see how local factors reshape them, and learn how the biosphere keeps every one of us alive.
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The living skin of the planet
The biosphere is the thin layer of Earth where living things exist. Across it, climate divides the world into great biomes, from steamy rainforests to frozen tundra. This module maps the biomes from the equator to the poles, and shows how the biosphere acts as a life-support system for every living thing, including us.
The language of the biosphere
Four ideas run through this module:
From the equator to the poles
Put these biomes in order, starting at the equator and moving toward the poles.
- Tropical rainforest, near the equator
- Hot desert, about 30 degrees from the equator
- Temperate forest, in the mid-latitudes
- Boreal forest, in the high northern latitudes
- Tundra, near the poles
Match each biome to its climate
- Tropical rainforest
- Hot desert
- Boreal forest
- Tundra
- Hot and wet all year round
- Hot and very dry
- Cold, with coniferous trees
- Freezing, with low-growing plants
Life at the equator
Which biome is found near the equator, where it is hot and wet all year?
- Tropical rainforest
- Hot desert
- Tundra
- Boreal forest
Local factors change the pattern
Latitude sets the broad pattern of biomes, but local factors change what grows in one place. Altitude makes higher land colder; the rock and soil decide what can root; drainage sets whether the ground is wet or dry; and aspect, the direction a slope faces, controls how much sunlight it gets.
Spot the local factors
Select the TWO LOCAL factors that affect where a biome is found.
- Altitude
- Drainage of the soil
- Distance from the equator
- The price of timber
A life-support system
The biosphere keeps us alive in two big ways: by giving us resources and by regulating the environment.
Match each biosphere service
- Regulating the atmosphere
- Regulating the soil
- Regulating water
- Providing resources
- Plants absorb carbon dioxide and release oxygen
- Roots hold the soil and recycle nutrients
- Storing and slowly releasing water
- Giving people food, wood and medicine
The biosphere in words
The _____ is the living layer of Earth, divided into large ecosystems called _____. Their global pattern is set mainly by _____, though local factors like altitude change it too. The biosphere gives people _____ such as food and timber, and it regulates the gases in the _____.
Living with the land
How do INDIGENOUS local people usually use the resources of a biome such as a rainforest?
- On a small scale, taking only what they need
- On a huge industrial scale for export
- By clearing all the forest at once
- Not at all, they never use it
Biomes and the biosphere
Tap the TWO statements that are TRUE.
- A biome is a large ecosystem defined by its climate.
- Plants in the biosphere absorb carbon dioxide and release oxygen.
- Tundra is a hot, wet biome found near the equator.
- Latitude is a local factor rather than a global one.
- The biosphere provides no useful resources for people.
Two ways to use a forest
Judge how a rainforest is being used in three situations.
- A local community hunts and gathers only what it needs, leaving the forest to recover. What kind of use is this?
- A company clears a large area of forest to plant a single crop for export. What kind of use is this?
- The cleared forest no longer absorbs as much carbon dioxide or holds the soil in place. Which biosphere services have been lost?
A life-support system
Explain why the biosphere is described as a life-support system. Describe the resources it provides for people, and at least two ways it regulates the environment.
- Explain what the biosphere is
- Describe the resources it provides, such as food, water and timber
- Explain how it regulates the atmosphere, for example the balance of gases
- Explain how it regulates the soil or the water cycle