AQA GCSE Trilogy Biology Paper 2 Foundation June 2023 question paper 8464/B/2F

Figure 1 shows a place where peat is being removed from a peat bog.

Why is peat removed from peat bogs? Tick (✓) one box.

Peat can decay. Name one type of organism that causes decay.

Complete the sentences. Choose answers from the box.

The organisms that cause decay respire. The gas used for respiration is. The gas produced by respiration is.

Peat bogs cover a total area of 3 700 000 km². In 2020, 46% of peat bogs were frozen.

How can the area of peat bogs that were frozen be calculated? Tick (✓) one box.

The percentage of peat bogs that are frozen decreases each year. Suggest why the percentage of peat bogs that are frozen is decreasing.

Which two human activities decrease the area of land available for other animals and plants? Tick (✓) two boxes.

A student investigated the effect of either seeing a stimulus or hearing a stimulus on reaction time.

First, the student measured their reaction time to seeing a colour change. This is the method used.

1. Sit in front of a computer with a reaction timer program open.

2. Press a key on the keyboard as quickly as possible when the computer screen changes colour.

3. Record the reaction time.

4. Repeat steps 1 to 3 four more times and calculate the mean reaction time.

Next, the student measured their reaction time to hearing a sound. This is the method used.

5. Sit in front of a computer with a reaction timer program open.

6. Press a key on the keyboard as quickly as possible when the computer produces a sound.

7. Record the reaction time.

8. Repeat steps 5 to 7 four more times and calculate the mean reaction time.

Table 1 shows some variables in this investigation.

Identify each variable as an independent variable, a dependent variable or a control variable. Tick (✓) one box in each row on Table 1.

How could the method be improved? Tick (✓) one box.

A shorter reaction time means the student reacted faster. The student reacted faster as each test was repeated. Suggest one reason why the student’s reactions got faster.

Table 2 shows the results.

Complete Figure 2. You should:

• plot the data from Table 2 as a bar chart

• label each bar

• label the y-axis.

Compare the reaction time when seeing the stimulus with the reaction time when hearing the stimulus.

A student investigated how the distance from a river affects the number of different plant species. Figure 3 shows a river between two fields.

A, B and C show the positions of three transects. Where should the student position another transect for this investigation? Draw the extra transect line on Figure 3.

The student recorded the number of different plant species at 1 m intervals along each transect.

Which piece of equipment should be used at 1 m intervals along the transect? Tick (✓) one box.

Figure 4 shows the results.

What was the mean number of different plant species 5 m from the river?

What is the effect of increasing distance from the river on the mean number of different plant species?

The minimum and maximum values on Figure 4 show the range of results at each distance from the river. Why is it useful to know the range of results? Tick (✓) one box.

Cows are kept in the fields. Fewer plants are found where the cows often walk on the ground. The number of cows is one biotic factor that affects the number of plants. Which two factors are abiotic factors? Tick (✓) two boxes.

Explain why a decrease in the number of plants across the world increases global warming.

Salmon are fish. A species of salmon has the binomial name Oncorhynchus keta.

Table 3 shows the classification for this species of salmon. Complete Table 3. Choose answers from the box.

Figure 5 shows sea lice attached to the skin of a salmon.

Sea lice are small animals that feed on the skin and blood of salmon. On a salmon farm, the salmon are fed with food made from soya plants.

Which food chain represents the salmon, sea lice and soya plants? Tick (✓) one box.

What do the arrows in a food chain represent? Tick (✓) one box.

Some salmon are more resistant than other salmon to sea lice infections. Salmon farmers selectively breed salmon.

Salmon farmers select salmon that are most resistant to sea lice and breed these salmon together. What is the next stage in selectively breeding salmon that are resistant to sea lice? Tick (✓) one box.

When is the process of selective breeding finished? Tick (✓) one box.

Salmon that do not have sea lice are more profitable for the salmon farmer. Suggest one reason why.

What is a disadvantage of selectively breeding salmon? Tick (✓) one box.

Other fish farmers have produced genetically modified (GM) salmon.

GM salmon grow large enough to sell in 18 months. Non-GM salmon grow large enough to sell in 3 years. GM salmon need 25% less food than non-GM salmon to get to the same size.

Suggest two advantages of farming GM salmon instead of farming non-GM salmon.

GM salmon are often farmed a long distance from where wild, non-GM salmon live. What is an advantage of farming GM salmon a long distance from where wild salmon live? Tick (✓) one box.

Homeostasis is the control of internal body conditions. Control of body temperature is an example of homeostasis.

Draw one line from each part involved in temperature control to the function of that part. Part involved in

Why is homeostasis important? Tick (✓) two boxes.

The body temperature of a long-distance swimmer can change with the

length of time swimming in cold water. Figure 6 shows how the body temperature of one swimmer changed in the first 4 hours of a 6-hour swim.

Describe the trend shown in Figure 6.

Determine the change in body temperature in the first 4 hours of the swim.

Hypothermia is a dangerously low body temperature of 35 °C or colder. Predict when the swimmer was first at risk of hypothermia. You should extend the line on Figure 6.

Swimming in cold water decreases the insulin concentration in the blood.

Complete the sentence. Choose the answer from the box.

Insulin is a hormone. Which organ system produces hormones?

Complete the sentence. Choose the answer from the box.

When insulin concentration in the blood increases, blood glucose concentration

Give one risk factor for Type 2 diabetes.

Sexual reproduction in humans involves the production of egg cells and sperm cells.

Name the type of cell division that produces egg cells and sperm cells.

Sexual reproduction produces offspring that are genetically different from each other. Give two reasons why sexual reproduction causes variation in the offspring.

Polydactyly is an inherited disorder.

The allele for polydactyly is dominant, D. A person with two copies of the allele d will not have polydactyly.

A person with the genotype DD is homozygous. What word describes the genotype Dd ?

A person with the genotype Dd and a person with the genotype dd plan to have a child. Determine the probability that the child will have polydactyly. You should:

• complete the Punnett square diagram

• identify any offspring genotype that would have polydactyly.

Embryos can be screened for the alleles that cause inherited disorders. Give two advantages of embryo screening.

It is estimated that 99.9% of all species that have ever existed are now extinct.

Why is the percentage of species that are extinct only an estimate? Tick (✓) one box.

What evidence is used to study species that have become extinct?

A bacterium called Clostridioides difficile (C. difficile) can infect the human digestive system. C. difficile can multiply and produce toxins. The toxins cause diarrhoea. Doctors are concerned that new strains of C. difficile may evolve. Antibiotics may not be able to kill these new strains. Explain how the evolution of antibiotic resistant C. difficile can be slowed down.