Sampling & fieldwork

Farmers can increase crop yield by controlling the conditions that plants grow in.

Draw one line from each substance to how the substance increases crop yield.

Figure 1 shows a food chain for a farmer’s field.

Figure 1

Which is the secondary consumer in the food chain?

Tick () one box.

Bees are insects that live in hives.

The bees fly in and out of the hives.

Figure 2 shows a crop growing in a field.

The farmer has added bee hives to increase the number of bees in the field.

Increasing the number of bees and other insects increases crop yield.

Which are two ways that increasing the number of insects in an area will increase crop yield?

Tick () two boxes.

Some farmers increase the size of hedgerows between fields where crops grow.

Suggest one reason why.

Peat comes from peat bogs.

Peat can be used to produce garden compost.

Table 1 compares peat compost with a sample of soil.

Young plants have short roots.

Explain one advantage of growing young plants in peat compost instead of in soil.

Peat can also be burnt as fuel.

Figure 3 shows part of the carbon cycle.

Name process A and process B.

Choose answers from the box.

Peat contains carbon compounds.

Explain why burning peat contributes to climate change.

Decay is an important process in the carbon cycle.

Which two types of organism cause decay?

Tick () two boxes.

Deforestation affects the carbon cycle.

Give one use of the land after the land has been cleared by deforestation.

Buttercups are small plants.

A student investigated the distribution of buttercup plants at different distances from a tree.

Figure 4 shows a piece of equipment being used to sample two areas.

What is the scientific name of the equipment shown in Figure 4 ?

Tick () one box.

Each small square on Figure 4 represents a percentage cover of 4%.

The student counted every small square that was at least half covered by buttercup plants.

At 1 metre away from the tree, buttercup plants had a percentage cover of 20%.

Determine the percentage cover of buttercup plants at 10 metres away from the tree.

Use Figure 4.

What is the independent variable in the investigation?

Tick () one box.

What is an advantage of calculating percentage cover instead of counting the number of buttercup plants in an area?

Tick () one box.

The student investigated the percentage cover of buttercup plants around a different tree.

Table 2 shows the results.

Calculate mean value X in Table 2.

Give one conclusion about the effect of distance from the tree on the percentage cover of buttercup plants.

Use Table 2.

Give two other factors that affect the percentage cover of buttercup plants around the tree.

Do not refer to distance from the tree.

Table 2 shows the results of the investigation.

Suggest two improvements to the investigation.

Buttercups are small plants.

Students investigated the distribution of buttercup plants at different distances from a tree.

Figure 2 shows quadrats being used to sample two areas.

What was the independent variable in this investigation?

Students counted every small square in the quadrat that was at least half covered by buttercup plants.

Determine the percentage cover of buttercup plants 10 metres away from the tree.

Use Figure 2.

The students placed:

• several quadrats 1 metre away from the tree

• several quadrats 10 metres away from the tree.

Give two factors the students should consider when deciding how many times to place a quadrat at each distance.

Do not refer to time available.

Figure 3 shows two different quadrats.

Explain two advantages of using quadrat B instead of quadrat A in the investigation.

You should include calculations in your answer.

A point quadrat can also be used to estimate the percentage cover of plants in an area.

Figure 4 shows a point quadrat.

When using a point quadrat, the pins are pushed down to the soil.

The number of pins that touch a buttercup plant is counted.

What are two advantages of using a point quadrat compared with using a square quadrat?

Tick () two boxes.

The percentage cover of buttercup plants can be estimated using the equation:

30 students each collected results from 50 pins.

The students then put all their results together.

Buttercup plants had a percentage cover of 7%.

Calculate the number of times a pin touched a buttercup plant.

Limpets are small animals with shells.

Limpets attach to rocks on sea shores.

Figure 9 shows limpets on rocks.

Limpets eat algae.

Limpets are prey for crabs.

Give the food chain for algae, crabs and limpets.

Students estimated the population of limpets on a sea shore.

The students were given a square quadrat.

Figure 10 shows the quadrat.

Calculate the area of the quadrat in m².

The total area of the sea shore was 1800 m².

The students sampled 2% of the total area of the sea shore.

Calculate the number of times the students needed to use the quadrat for the 2% sample.

Use your answer from Question 05.2

Explain why throwing a quadrat is not a random method to estimate population size.

Do not refer to safety in your answer.

Describe one method the students could use to plan where the quadrat should be randomly placed each time.

Suggest one hazard the students should be aware of when collecting data on the sea shore.

Do not refer to throwing quadrats in your answer.

Populations of limpets are monitored to assess the impact of pollution in water.

Suggest one type of pollution in water that may affect the population of limpets.

Limpets are small animals with shells.

Limpets attach to rocks on sea shores.

Figure 1 shows limpets on rocks.

Limpets eat algae.

Limpets are prey for crabs.

Give the food chain for algae, crabs and limpets.

Students estimated the population of limpets on a sea shore.

The students were given a square quadrat.

Figure 2 shows the quadrat.

Calculate the area of the quadrat in m².

The total area of the sea shore was 1800 m².

The students sampled 2% of the total area of the sea shore.

Calculate the number of times the students needed to use the quadrat for the 2% sample.

Use your answer from Question 01.2

Explain why throwing a quadrat is not a random method to estimate population size.

Do not refer to safety in your answer.

Describe one method the students could use to plan where the quadrat should be randomly placed each time.

Suggest one hazard the students should be aware of when collecting data on the sea shore.

Do not refer to throwing quadrats in your answer.

Populations of limpets are monitored to assess the impact of pollution in water.

Suggest one type of pollution in water that may affect the population of limpets.

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.

Figure 1 shows a river next to a field.

Describe a method to investigate how the distance from the river affects the number of different plant species in the field. You should explain how to use a transect in your method.

Students used a valid method to investigate how the distance from the river affects the number of different plant species in the field. Figure 2 shows the results.

What is shown by the data in Figure 2 ? Tick (✓) one box.

Cows walk on the ground near the river more than they walk on the ground further

from the river.

Which is an abiotic factor that could affect the number of different plant species found near the river? Tick (✓) one box.

Increasing numbers of cows are being farmed across the world. Explain the environmental implications of increasing numbers of cows being farmed.

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. On the field the students marked out:

• an area of 10 m by 10 m on the wet soil

• an area of 10 m by 10 m on the dry soil.

Describe how a quadrat can be used to measure the size of the buttercup population on the wet soil area.

What type of factor is water in the soil? Tick (✓) one box.

Give two factors which might affect the number of buttercups growing on the school field. Do not refer to water in your answer.

Complete the sentence. Choose the answer from the box.

In this investigation the number of buttercups in each quadrat was

Figure 2 shows a quadrat on an area of the school field.

Calculate the area of the quadrat.

The mean number of buttercups in one quadrat was 8 Calculate the number of buttercups per m² Use your answer from Question 02.5

In a laboratory another group of students investigated the effect of soil acidity on the growth of beans. This is the method used.

1. Put soil with a neutral pH in two large boxes.

2. Add acid to the soil in one box.

3. Plant some bean seeds in each box.

4. Water the seeds over 3 weeks.

5. After 3 weeks, measure the height of the bean plants in each box.

6. Calculate the mean height of bean plants in each box.

Give two improvements the students could make to the method to give more valid results.

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

Calculate mean value X in Table 1.

What conclusion can the students make about the effect of acid soil on the growth of bean plants?

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.

Figure 2 shows one species of bird on a bird feeder.

The birds use their beaks to reach nuts inside the bird feeder.

Cats sometimes eat the birds.

Give the food chain for the birds, cats and nuts.

Which organism in the food chain you gave in Question 03.1 is the primary consumer?

Cats are one biotic factor that affects the size of the bird population.

Which two of the following are biotic factors?

Tick (✓) two boxes.

Figure 3 shows the mean beak length of this species of bird from 1982 to 2007.

What was the mean beak length in 2000?

What type of adaptation is beak length?

Tick (✓) one box.

Figure 3 shows evidence of evolution in this species of bird.

Scientists have concluded that beak length in this species of bird is increasing.

Complete the sentences about the evolution of this species of bird.

Choose answers from the box.

The difference in beak length in the bird population

is called.

A change in a gene affects the beak length.

Change in a gene is called.

The birds with the longest beaks get more food.

Getting more food improves a bird’s chances of

survival and.

This process of evolution takes place over more

than one.

Birds of this species:

• live for about 3 years

• produce up to 24 eggs every year.

Why is evolution easier to study in birds than in humans?

Tick (✓) one box.

Bacteria also provide evidence for evolution.

Which statement describes evidence for evolution?

Tick (✓) one box.

Caffeine is a drug that decreases reaction time. A group of sixteen students investigated the effect of caffeine on reaction time. The students were all 15-year-old girls. The group was divided into 8 pairs of students. This is the method used.

1. Student A starts two stopwatches at the same time.

2. Student A then gives one of the stopwatches to Student B.

3. Student A says “stop” at the same time as stopping her stopwatch. Student B stops her stopwatch as quickly as possible after Student A says “stop”.

4. The difference in time shown on the two stopwatches is recorded. This is the reaction time of Student B.

5. Student B drinks a caffeinated drink.

6. The students wait 15 minutes and then repeat steps 1 to 4.

Suggest one control variable the students should have used in the investigation. Do not refer to age or sex in your answer.

Suggest two sources of random error when using this method to measure a person’s reaction time.

Table 1 shows the results.

Why can a mode not be determined for the data in Table 1 ?

The students decided the result from pair 8 was anomalous. The students calculated that the mean decrease in reaction time was 0.030 seconds. Describe how the students calculated the mean decrease in reaction time.

Caffeine causes the release of adrenaline. Adrenaline affects heart rate. Explain how the effect of adrenaline on heart rate might cause reaction time to decrease.

Adenosine is a different chemical made by the body.

Adenosine binds to receptors on relay neurones. Adenosine decreases the number of impulses in relay neurones. Figure 5 shows how caffeine binds to adenosine receptors on a relay neurone. When caffeine binds to adenosine receptors it blocks the receptor so adenosine cannot bind.

Label X shows the gap between the sensory neurone and the relay neurone. What is the name of the gap labelled X ?

Suggest why reaction time decreases when caffeine binds to adenosine receptors.

This question is about biodiversity. A farmer:

• grows only wheat crops

• has used all his small fields to make a few large fields

• cuts down trees in his woodlands to burn as fuel.

What are two ways the farmer could increase biodiversity on his farm? Tick (✓) two boxes.

Students investigated the effect of cutting down trees in the woodland. This is the method used.

1. Mark out a 10 m by 10 m area where trees have been removed.

2. Place a 1 m × 1 m quadrat at six random positions in the area.

3. Record the number of plant species present.

4. Record the number of invertebrate species seen among dead leaves on the ground.

5. Repeat steps 1 to 4 in an area where there are trees.

Suggest one improvement the students could make to their method.

The students made this prediction: ‘There will be more invertebrate species living in the area where there are trees.’

Explain why the students’ prediction may be correct.

Table 1 shows the students’ results.

The students decided that one result was anomalous. Draw a ring around the anomalous result in Table 1.

How does removing trees affect the number of invertebrate species living among the dead leaves on the ground? Use Table 1.

There were more plant species growing in the area where there were no trees. Explain why.

Human reactions are a response to an external change.

Reflex actions help to protect the body against damage. Figure 2 shows the nervous pathway for a reflex action.

A stimulus from the hot pan will cause the muscle in the arm to contract and move the finger away. Describe how the stimulus from the hot pan reaches the muscle in the arm.

A student investigated whether using the right hand or the left hand had an effect on reaction time. The student only tested right-handed people. Describe a method for the student’s investigation. Include details of the test you would use for reaction time.

A different student carried out an investigation to see if playing tennis improved reaction time. The student used two groups of six people. Table 1 shows the results.

Calculate mean value X in Table 1.

What is the dependent variable in the student’s investigation?

The student concluded: ‘Playing tennis improves reaction time.’

Give one piece of evidence which supports the conclusion.

Give one piece of evidence which does not support the conclusion.

Some students estimated the population of daisy plants in a field.

This is the method used.

1. Place a quadrat randomly on the field.

2. Count and record the number of daisy plants in the quadrat.

3. Repeat steps 1 and 2 another four times.

How could the students have made sure the quadrats were placed randomly?

Describe the piece of equipment called a quadrat.

Table 1 shows the results.

Calculate mean value X.

The field is a rectangle 100 m wide and 150 m long.

Calculate the area of the field.

The quadrat used by the students had an area of 1.0 m²

Estimate the population of daisy plants in the field.

Use your answers to Question 02.3 and Question 02.4

More daisy plants grew in some parts of the field compared to other areas of the field.

Give two biotic factors that may affect where daisy plants grow in the field.

The students noticed that the daisy plants growing near a building were smaller.

Explain why smaller daisy plants grew near the building.

Figure 4 shows a food chain in a garden.

bean plant → blackfly → spider → blackbird

Which term describes the spider in this food chain?

Tick (✓) one box.

Many of the spiders in the garden died.

What is likely to happen to the number of blackflies in the garden?

Tick (✓) one box.

Give a reason for your answer to Question 05.2

Table 2 shows the estimated biomass of organisms in the garden.

What conclusion can be made about biomass in food chains?

Complete Figure 5.

You should:

• label the y-axis

• plot the data from Table 2.

Explain why a garden is not a stable community.

Some students estimated the population of daisies in a school field. This is the method used.

1. Find a place where some daisies are growing.

2. Put the quadrat down.

3. Count and record the number of daisies in the quadrat.

4. Repeat steps 1–3 at four different places in the field.

5. Calculate the mean number of daisies per quadrat.

6. Use the data to estimate the total number of daisies in the field.

Which two improvements would increase the validity of this method? Tick (✓) two boxes.

With an improved method the students calculated the mean number of daisy plants to be 7.65 per quadrat. The students used a quadrat measuring 50 cm × 50 cm Figure 3 shows the school site and the dimensions of the school field.

Calculate the population of daisy plants on the school field. Give your answer in standard form to 2 significant figures.

The students noticed a very uneven distribution of daisy plants in the field. Explain how different biotic factors and abiotic factors could have caused an uneven distribution of daisy plants. Use Figure 3 on page 20.

A class of eight students measured the population of water fleas living at the edge of a large pond.

This is the method each student used.

1. Put some pond water in a white tray.

2. Take a pond net and scoop at the edge of the pond a few times.

3. Empty the pond net into the water in the tray.

4. Count the number of water fleas in the tray.

Figure 6 shows a student working.

The students did not control some variables.

Give two variables the students should have controlled to make this a valid method.

The eight students then used a different method to obtain valid results.

Table 2 shows their results.

Calculate the students’ mean value for the population of water fleas at the edge of the pond.

What was the range of the students’ results?

Suggest one reason why such a wide range of results was found.

The teacher then sampled the centre of the pond eight times.

His mean value was 12 water fleas per 1000 cm³ pond water.

What conclusion can you make about the distribution of water fleas in the pond?

Use the students’ mean value from question 04.2 to compare with the teacher’s mean value.

Scientists counted some different invertebrates living in a pond in 2014 and in 2016

Table 3 shows the results.

Calculate the change in the number of bloodworms between 2014 and 2016

Calculate the number of shrimps in the pond in 2016 as a percentage of the number of shrimps in the pond in 2014

Invertebrate species found in a pond can be used as an indicator of the pollution level.

Table 4 shows which species can survive in different levels of pollution.

What conclusion can you make about the change in the level of pollution in the pond between 2014 and 2016?

Give one reason for your conclusion.

Use the data in Table 3 and Table 4

Water pollution and global warming are two problems that have been caused by the rapid increase of the human population.

Suggest two other problems caused by the rapid increase of the human population.

Many biotic and abiotic factors can affect the growth of plants.

Are the factors in Table 6 biotic or abiotic?

Tick one box for each factor.

Two students investigated the effect of light intensity on the distribution of small plants.

The plants are growing under a tree in a park.

The students made the following hypothesis:

‘As you move outwards from a tree there will be more plant growth.’

Explain why the students thought their hypothesis would be correct.

The students used two pieces of equipment.

Give the scientific name of each piece of equipment.

A square frame measuring 0.5 m × 0.5 m

An electronic device to measure light intensity

This is the method used.

1. Fix one end of a tape measure at the base of the tree.

2. Fix the other end of the tape measure 11 metres from the tree.

3. At 0 metres put the square frame on the ground.

4. Identify all the plant species growing inside the frame.

5. Estimate and record the percentage cover of each plant species.

6. Measure the light intensity inside the frame.

7. Put the square frame on the ground every 2 metres along the tape to 10 metres.

8. Repeat steps 4 – 6 in every frame.

Figure 9 shows the equipment in this investigation.

Calculate the total area sampled.

The whole investigation was done as quickly as possible on the same day.

Suggest one reason why.

Give one way the investigation could be improved.

Table 7 shows the results.

Which plant species in Table 7 will only grow at high light intensity?

What conclusion can be made about the relationship between light intensity and the total percentage cover of plants?

Use data from Table 7 in your answer.

Light intensity might not be the cause of this pattern of plant distribution.

Suggest one different factor that may cause these results.

Give one reason for your answer.