Global warming

Peat bogs are estimated to contain twice as much carbon as all the world’s forests.

Figure 13 shows a section through part of a peat bog.

Layer A contains a lot of air.

Layer B:

• contains the dead remains of plants

• has a low pH

• contains very little oxygen

• contains carbon dioxide and methane.

Explain why most of the dead remains of plants in layer B do not decay.

The peat bog in Figure 13 is a stable community.

The moss produces biomass at a rate of 340 g/m²/year.

What is the approximate biomass of the moss that becomes biomass in primary

Tick (✓) one box.

The sundew plant shown in Figure 13 on page 38 has leaves with sticky hairs that trap and digest insects.

Digestion of the insects releases phosphates and simple compounds of nitrogen that are used by the sundew plant.

What substance can the sundew plant make using the phosphates ?

Tick (✓) one box.

What substance can the sundew plant make using the nitrogen ?

Tick (✓) one box.

Humans have destroyed large areas of peat bog to collect peat.

The peat provides fuel and provides compost for gardeners to use.

The peat comes from layer B in Figure 13 on page 38.

Layer B:

• contains the dead remains of plants

• has a low pH

• contains very little oxygen

• contains carbon dioxide and methane.

Figure 14 shows the removal of peat from a peat bog.

Explain how the destruction of peat bogs and the use of peat affects the temperature of the Earth’s atmosphere.

Peat bogs are estimated to contain twice as much carbon as all the world’s forests.

Figure 2 shows a section through part of a peat bog.

Layer A contains a lot of air.

Layer B:

• contains the dead remains of plants

• has a low pH

• contains very little oxygen

• contains carbon dioxide and methane.

Explain why most of the dead remains of plants in layer B do not decay.

The peat bog in Figure 2 is a stable community.

The moss produces biomass at a rate of 340 g/m²/year.

What is the approximate biomass of the moss that becomes biomass in primary

Tick () one box.

The sundew plant shown in Figure 2 on page 4 has leaves with sticky hairs that

trap and digest insects.

Digestion of the insects releases phosphates and simple compounds of nitrogen that are used by the sundew plant.

What substance can the sundew plant make using the phosphates ?

Tick () one box.

What substance can the sundew plant make using the nitrogen ?

Tick () one box.

Humans have destroyed large areas of peat bog to collect peat.

The peat provides fuel and provides compost for gardeners to use.

The peat comes from layer B in Figure 2 on page 4.

Layer B:

• contains the dead remains of plants

• has a low pH

• contains very little oxygen

• contains carbon dioxide and methane.

Figure 3 shows the removal of peat from a peat bog.

Explain how the destruction of peat bogs and the use of peat affects the temperature of the Earth’s atmosphere.

Scientists are very concerned about the changes in concentration of carbon dioxide in the Earth’s atmosphere. Figure 12 shows the concentration of carbon dioxide in the atmosphere between 1988 and 2014.

Describe two patterns shown in Figure 12. Use data from Figure 12 in your answer.

Give two human activities that affect the concentration of carbon dioxide in the atmosphere.

The trend shown in Figure 12 may continue for many years. Explain what effect the changing concentration of carbon dioxide in the atmosphere could have on living organisms.

Figure 10 shows a flightless bird called the dodo (Raphus cucullatus).

The dodo:

• was 1 m tall

• had a mass of 20 kg

• lived in rainforests on a tropical island

• ate fruits

• made its nest on the ground.

A female dodo laid only one egg each year.

Humans arrived on the island in the year 1507. By 1681 the dodo was extinct.

What is the genus of the dodo?

Tick (✓) one box.

Before the arrival of humans, there were no other large animals living on the island.

Suggest two reasons why the dodo became extinct soon after the arrival of humans.

Today, humans are cutting down large areas of tropical rainforests.

Suggest one use of the land after the trees have been removed.

Why does the removal of trees cause an increase in carbon dioxide in the atmosphere?

Tick (✓) two boxes.

What effect would an increase in carbon dioxide in the atmosphere have on global air temperature?

Tick (✓) one box.

‘Sustainable forestry’ reduces the harmful effects of cutting down trees on the environment.

Figure 11 shows a method of ‘sustainable forestry’.

Numbers 1–9 show different parts of a rainforest.

The trees are cut down in the sequence 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9

• The trees are cut down in only one area at any one time.

• It takes 30 years to cut down the trees in each area.

• The trees in the ‘Old growth’ area are never cut down.

How many years would it take to cut down the trees in all of the numbered areas in Figure 11 ?

The rainforest contains:

• 750 species of trees

• 400 species of birds

• 150 species of butterflies

• many other species of plants and animals.

Explain how the pattern of cutting down trees shown in Figure 11 stops the biodiversity of the rainforest being reduced.

Many scientists think that global air temperature is related to the concentration of carbon dioxide in the atmosphere.

Figure 14 shows changes in global air temperature and changes in the concentration of carbon dioxide in the atmosphere.

Complete Table 4. Use information from Figure 14.

Choose answers from the box.

You may use each answer once, more than once or not at all.

Many scientists think that an increase in carbon dioxide concentration in the atmosphere causes an increase in air temperature.

How would an increase in the concentration of carbon dioxide in the atmosphere cause an increase in air temperature?

Evaluate evidence for and against the theory that an increase in the concentration of carbon dioxide in the atmosphere causes an increase in air temperature.

Use data from Figure 14 and your own knowledge.

In each year, the concentration of carbon dioxide in the atmosphere is higher in the winter than in the summer.

Give one human activity that could cause the higher concentration of carbon dioxide in the winter.

Give one biological process that could cause the lower concentration of carbon dioxide in the summer.

Give two possible effects of an increase in global air temperature on living organisms.

Many scientists think that global air temperature is related to the concentration of carbon dioxide in the atmosphere.

Figure 3 shows changes in global air temperature and changes in the concentration of carbon dioxide in the atmosphere.

Complete Table 1. Use information from Figure 3.

Choose answers from the box.

You may use each answer once, more than once or not at all.

Many scientists think that an increase in carbon dioxide concentration in the atmosphere causes an increase in air temperature.

How would an increase in the concentration of carbon dioxide in the atmosphere cause an increase in air temperature?

Evaluate evidence for and against the theory that an increase in the concentration of carbon dioxide in the atmosphere causes an increase in air temperature.

Use data from Figure 3 and your own knowledge.

In each year, the concentration of carbon dioxide in the atmosphere is higher in the winter than in the summer.

Give one human activity that could cause the higher concentration of carbon dioxide in the winter.

Give one biological process that could cause the lower concentration of carbon dioxide in the summer.

Give two possible effects of an increase in global air temperature on living organisms.