AQA GCSE Trilogy Biology Paper 2 Higher June 2022 question paper 8464/B/2H

This question is about the cycling of water and carbon in ecosystems.

Which reaction produces water? Tick (✓) one box.

The water cycle provides water for plants and animals on land before the water goes into lakes and seas.

Figure 1 represents the water cycle.

Name the processes 1 to 5 shown on Figure 1.

In 2007 the population of the world was 6 000 000 000 A study found that 4.5% of the population had severe water shortage.

Calculate how many people had severe water shortage. Give your answer in standard form.

Why do more people have severe water shortage now than in 2007? Tick (✓) two boxes.

Leaves on a tree contain carbon compounds. In autumn the leaves fall to the ground.

Microorganisms in the soil recycle carbon from the leaves so that the carbon is used for new plant growth. Explain how.

What is one benefit of fallen leaves for living plants? Tick (✓) one box.

Water pollution is a problem for humans and wildlife. Explain how human activities are polluting rivers, lakes and seas.

On a school field:

• one area of the soil was usually wet

• another area of the soil was usually dry.

Students investigated the effect of water in the soil on the number of buttercup plants growing in each area.

Water is an abiotic factor. Name one biotic factor which may affect the number of buttercups growing on the field.

Describe a method to investigate if the amount of water in the soil affects the number of buttercups in the field.

Scientists investigated the effect of soil nitrate ion concentration on the yield of corn. This is the method used.

1. Corn plants were grown in a large box of soil.

2. The soil nitrate ion concentration in the box was kept at 0 parts per million (ppm).

3. All the corn from each plant in the box was removed and weighed.

4. The mean mass of corn per plant was calculated.

5. Steps 1 to 4 were repeated for boxes containing soil with different concentrations of nitrate ions.

Figure 2 shows the corn plants in the box with a 20 ppm soil nitrate ion concentration.

Give two variables the scientists should have controlled in this investigation.

The scientists carried out a valid investigation. Table 1 shows the scientists’ results.

Complete Figure 3. You should:

• label the y-axis

• use a suitable scale for the y-axis

• plot the data from Table 1

• draw a line of best fit.

Table 1 is repeated below.

Describe the relationship between soil nitrate ion concentration and the mean mass of corn per plant. Use data from Table 1 in your answer.

Farmers add nitrate fertiliser to fields where they grow corn. Nitrate fertilisers are expensive.

Evaluate the economic and environmental implications of adding fertiliser to soil in nitrate ion concentrations ranging from 0 to 50 ppm

Blood glucose concentration in the human body needs to be kept within the normal range. Figure 4 shows that two hormones control blood glucose concentration.

Name the type of hormonal control shown in Figure 4.

Name hormones A and B in Figure 4.

Explain how the two hormones in Figure 4 keep the blood glucose concentration within the normal range for 3 hours after a meal.

Female reproductive hormones are used to treat infertility in women.

Follicle Stimulating Hormone (FSH) and then Luteinising Hormone (LH) can be injected into a woman to help her become pregnant by sexual intercourse. Explain how injecting FSH and then LH will help a woman to become pregnant.

In some women the injections of FSH and LH are the first steps for In Vitro Fertilisation (IVF). Describe the remaining steps in IVF.

There are two different processes of cell division in humans. Describe three differences between cell division to form sperm cells compared with cell division to form liver cells.

The polar bear is a mammal that lives in arctic habitats.

Complete Table 2 for the classification of the polar bear, Ursus maritimus.

Scientists have been measuring the area of sea ice in the Arctic since 1980. Figure 5 shows the area covered by sea ice every September.

Determine the annual rate of loss of sea ice between 1985 and 2017. A trend line has been drawn on Figure 5 to help you.

The total number of polar bears living on the arctic ice is not known. The hunting of polar bears has been banned or reduced in some areas. In some populations the average mass and height of polar bears has decreased. Polar bears eat seals. Seals live on the sea ice in winter and raise their pups there in early spring. In the summer seals live mainly in the sea catching fish to eat. Polar bears spend much of the year hunting seals on the sea ice and in the sea nearby. The sea ice area is at its lowest each year in September at the end of summer. The polar bears feed mainly in early spring, and again in autumn to build fat stores to survive the next winter. During the winter of 2017 scientists measured the metabolic rates of nine female polar bears and found them to be much higher than expected. Cameras attached to the female polar bears showed they had to swim long distances to find seals to eat.

Suggest why polar bears find it harder to catch seals in autumn than in spring.

Evaluate what might happen to the population of polar bears in the Arctic in the future.