Resources and environment, Year 8: more practice

The emergent layer

HintThink of the trees that stand clear above everything else.

The whyEmergent trees can reach 40 to 50 metres or more. They get full sunshine and strong wind.

The forest floor

HintLittle sunlight reaches it.

The whyVery little sunlight reaches the floor. Fallen leaves rot quickly there.

To shed heavy rain quickly

HintIt helps with the water that falls every day.

The whyRainforests have rain almost daily. Quick run-off keeps the leaves clear of fungi and algae.

In the leaf litter and the living plants, not deep in the soil

HintHeavy rain washes nutrients out of the ground.

The whyDead leaves rot fast in the heat and are absorbed by roots almost at once, so nutrients move quickly in a loop.

Soy (soya)

HintIt feeds farm animals around the world.

The whyLarge soy farms and cattle ranches are the main drivers of clearance in the Amazon basin.

Indonesia and Malaysia

HintBoth are on or near Borneo and Sumatra.

The whyPalm oil is used in food, cosmetics and fuel. Most of it comes from these two countries.

Trees store carbon, which is released when they are burnt or rot, and fewer trees remain to absorb carbon dioxide

HintThink about what gas plants take in from the air.

The whyForests are a carbon store and a carbon sink. Clearing them reduces absorption and releases stored carbon.

Coal

HintNatural gas is the cleaner of the two.

The whyCoal releases much more carbon dioxide than natural gas for the same energy.

It only produces power when the sun is shining

HintThink about the weather and the night.

The whyGas can run whenever it is needed, whereas solar output varies with cloud and daylight.

It sits on a plate boundary, so hot rock lies close to the surface

HintThink about volcanoes and the Earth's crust.

The whyIceland lies on the Mid-Atlantic Ridge. Heat from underground heats water, giving steam that turns turbines.