Biodiversity

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

Maize is a crop plant.

A variety of maize has been genetically modified (GM) to be resistant to a herbicide.

Explain how growing GM herbicide-resistant maize can produce a larger yield than growing non-GM maize.

Explain how growing a GM herbicide-resistant crop can decrease the biodiversity of animals.

Bees are a type of insect.

The number of insects near a crop can be increased by planting hedgerows.

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

Suggest two reasons why increasing the number of insects can increase crop yield.

Hedgerows provide habitats for insects.

Give one reason why increasing hedgerow habitats increases insect numbers.

Some farmland contains areas of peat.

When peat is dug up:

• the oxygen levels in the peat increase

• the peat decays quickly.

Explain why increasing the level of oxygen in peat contributes to climate change.

Otters are mammals that live in river ecosystems.

Figure 5 shows an otter.

Define the term ‘ecosystem’.

Otters are an important species for the stability of the river community.

Describe two ways animal species may be important for the stability of a whole community.

Sewage was accidentally added to a river.

The sewage moved with the river water and affected:

• the number of bacteria in the water

• the concentration of dissolved oxygen in the water.

Samples of river water were analysed at different distances from where the sewage was added.

Table 2 shows the results.

The number of bacteria at 5.0 km was greater than the number of bacteria where the sewage was added.

Calculate how many times greater.

A student concluded:

‘number of bacteria concentration of dissolved oxygen’

Explain why the student’s conclusion is not correct.

Use Table 2.

Otters:

• live in water and on the land

• eat mainly fish.

The concentration of dissolved oxygen has decreased in a river where otters live.

Explain how the decrease in the concentration of dissolved oxygen in the river water will affect the population of otters.

Figure 6 shows the money spent on conserving biodiversity in the UK by the government.

Describe the trends in the money spent on conserving biodiversity from 2005 to 2011.

Use data from Figure 6 in your answer.

Calculate the percentage decrease in the money spent on conserving biodiversity from 2013 to 2017.

Use the equation:

Give your answer to 2 significant figures.

Conservation of peat bogs can help maintain biodiversity.

Give two uses of peat taken from peat bogs.

Describe two ways to increase biodiversity in the UK.

Do not refer to money spent or to peat in your answer.

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.

There is a need to grow enough food for all the people in the world. Growing enough food affects habitats and biodiversity.

What is meant by the term biodiversity?

Peat bogs are being destroyed because peat is used by humans. Destroying peat bogs also reduces biodiversity.

Give one use of peat taken from peat bogs.

Explain why the use of peat is harmful to the environment. Do not refer to biodiversity in your answer.

Intensive farming, where a single crop is grown on a large area of land year after year, is more cost effective for farmers. It is efficient to use fertilisers and to burn the waste so the land is ready to use the next year. Planting a single crop reduces biodiversity. Suggest two ways that this type of farming can damage the environment. Do not refer to biodiversity in your answer.

Most of the world’s production of antibiotics is used in farming. Antibiotics are given to animals to prevent the spread of disease.

Explain how the widespread use of antibiotics in farming is a threat to human life.

Animals have adaptations to survive in their environment.

These adaptations may be structural, behavioural or functional.

Draw one line from each animal adaptation to the type of adaptation it is.

Animal adaptation
Type of adaptation

Plants also have adaptations.

Orchid plants have adaptations which make them one of the most successful plant groups.

Orchids rely on insects for pollination.

Figure 2 shows an orchid.

Which two features help orchids survive?

Tick (✓) two boxes.

Many orchid species grow in tropical rainforest ecosystems.

What name describes the variety of all the different species found in an ecosystem?

Tick (✓) one box.

Some species of orchid may become extinct because of deforestation.

Give one reason why tropical rainforests are being cut down.

Give one factor that might cause a species of orchid to become extinct.

Do not refer to deforestation in your answer.

Scientists have analysed the entire genetic material of one species of orchid.

What chemical is the genetic material made from?

What is the name for the entire genetic material of an organism?