Biodiversity

Define the biological term population.

Ecologists monitored the biodiversity of birds in a protected woodland.

They recorded the number of bird species breeding in the woodland on the same day, every year for a 30-year period.

Figure 4 shows their results.

Figure 4

Figure 4 not reproduced here due to third-party copyright restrictions

The figure is taken from the following website:

Figure 1a. Anne E. Magurran, Stephen R. Baillie, Stephen T. Buckland, Jan McP. Dick, David A. Elston, E. Marian Scott, Rognvald I. Smith, Paul J. Somerfield, Allan D. Watt, Long-term datasets in biodiversity research and monitoring: assessing change in ecological communities through time, Trends in Ecology & Evolution, Volume 25, Issue 10, 2010, Pages 574-582, ISSN 0169-5347, https://doi.org/10.1016/j.tree.2010.06.016.

Which statement correctly represents the species richness of the woodland?

Tick () one box.

A student studying the information in this question concluded that all woodlands should be protected to increase the biodiversity of birds.

Evaluate the student’s conclusion.

It is not possible to extrapolate the data for the number of bird species recorded breeding each year beyond 1979.

Explain why.

In this woodland, the ecologists measured the similarity in the bird community by comparing each year to 1949 using an index of similarity.

This index ranges from 1.0 for total similarity to 0.0 for total dissimilarity.

Figure 5 shows their results.

Figure 5

Figure 5 not reproduced here due to third-party copyright restrictions

The figure is taken from the following website:

Figure 1b, Anne E. Magurran, Stephen R. Baillie, Stephen T. Buckland, Jan McP. Dick, David A. Elston, E. Marian Scott, Rognvald I. Smith, Paul J. Somerfield, Allan D. Watt, Long-term datasets in biodiversity research and monitoring: assessing change in ecological communities through time, Trends in Ecology & Evolution, Volume 25, Issue 10, 2010, Pages 574-582, ISSN 0169-5347, https://doi.org/10.1016/j.tree.2010.06.016.

Suggest how the changes in the index of similarity in the bird community provide evidence for the process of succession.

In Figure 5, the index of similarity for the last 10 years remains fairly constant.

Name the stage of a succession this represents.

Suggest one reason why the index of similarity is not absolutely constant.

The Living Planet Index (LPI) is an index designed to monitor the state of the world’s biodiversity.

The LPI is arbitrarily scaled to be 1.0 in 1970, the baseline year.

Figure 6 shows the LPI from the Living Planet Report, 2008. The dotted lines represent ± 2 standard deviations from the mean, which includes over 95% of the data.

Figure 7 shows an alternative version of Figure 6 published on a news website.

Figure 6 Figure 7

Figures 6 and 7 not reproduced here due to third-party copyright restrictions

The figures are taken from the following website:

Figure 2a and 2b, Anne E. Magurran, Stephen R. Baillie, Stephen T. Buckland, Jan McP. Dick, David A. Elston, E. Marian Scott, Rognvald I. Smith, Paul J. Somerfield, Allan D. Watt, Long-term datasets in biodiversity research and monitoring: assessing change in ecological communities through time, Trends in Ecology & Evolution, Volume 25, Issue 10, 2010, Pages 574-582, ISSN 0169-5347, https://doi.org/10.1016/j.tree.2010.06.016.

The news website published the headline:

The LPI shows human activities cause significant decrease in biodiversity.

Suggest three reasons why this headline is not valid.

Use all the information provided.

Turn over for Section B

Section B

one question.

You are advised to spend no more than 45 minutes on this section.

Scientists investigated the effect that the release of heated water into a river from a power station had on the biodiversity of a local fish community over 29 years.

They measured the species richness and the number of fish of each species at the same site in October every year. The scientists used this information to calculate an index of diversity (d) of fish for each year.

Figure 7 and Figure 8 show their results.

The scientists used the following formula to calculate the index of diversity (d) of fish.

where N = total number of fish of all species and n = total number of fish of each species

In some years, the values were N = 624 and Σ n (n –1) = 64 792

Which years had these values?

Use Figure 8 and the formula above to work out your answer.

In 1997, the scientists recorded the highest species richness, but the lowest value of d over the 29 years.

Describe and explain how these results for 1997 were possible.

A journalist studied Figure 7 and Figure 8 (on page 16) and concluded that releasing heated water from a power station has no effect on local fish communities.

Use all the information to suggest reasons why the journalist’s conclusion might not be valid.

Describe the structure and function of the nucleus.

Name the main polymer that forms the following cell walls.

Scientists investigated the effect of the number of fungal species in soil on the diversity of plant species.

Table 1 shows their raw data for soil containing 14 fungal species.

Suggest one reason the scientists used biomass instead of the number of individuals of each plant species when collecting data to measure diversity.

The scientists used this equation to calculate the plant species index of diversity.

where n = shoot biomass of each plant species and N = total shoot biomass of all plant species

Use this equation to calculate the index of diversity for the data in Table 1.

Index of diversity

Figure 1 shows the plant species index of diversity the scientists calculated when the soil contained 0, 1, 2, 4 and 8 fungal species.

Figure 1

Figure 1 not reproduced here due to third-party copyright restrictions

Sometimes farmers stop growing crops on an area of land to allow the natural ecosystem to recover. The plant species index of diversity of these areas previously used to grow crops is different from nearby land that has never been used to grow crops.

Suggest and explain how the plant species index of diversity would be different in these areas previously used to grow crops.

Use Figure 1 and your knowledge of the effect of farming on biodiversity in your answer.

A group of students investigated biodiversity of different areas of farmland. They collected data in each of these habitats:

• the centre of a field

• the edge of a field

• a hedge between fields.

Their results are shown in Figure 4.

What data would the students need to collect to calculate their index of diversity in each habitat?

Do not include apparatus used for species sampling in your answer.

Give two ways the students would have ensured their index of diversity was representative of each habitat.

Modern farming techniques have led to larger fields and the removal of hedges between fields.

Use Figure 4 to suggest why biodiversity decreases when farmers use larger fields.

Farmers are now being encouraged to replant hedges on their land.

Suggest and explain one advantage and one disadvantage to a farmer of replanting hedges on her farmland.

Bees are flying insects that feed on nectar made in flowers. There are many different species of bee.

Scientists investigated how biodiversity of bees varied in three different habitats during a year. They collected bees from eight sites of each habitat four times per year for three years.

The scientists’ results are shown in Figure 4 in the form they presented them.

What is meant by ‘species richness’?

From the data in Figure 4, a student made the following conclusions.

1. The natural habitat is most favourable for bees.

2. The town is the least favourable for bees.

Do the data in Figure 4 support these conclusions? Explain your answer.

1. The natural habitat is most favourable for bees.

2. The town is the least favourable for bees.

The scientists collected bees using a method that was ethical and allowed them to identify accurately the species to which each belonged.

In each case, suggest one consideration the scientists had taken into account to make sure their method

2. allowed them to identify accurately the species to which each belonged.

Suggest and explain two ways in which the scientists could have improved the method used for data collection in this investigation.

Three of the bee species collected in the farmland areas were Peponapis pruinosa, Andrena chlorogaster and Andrena piperi.

What do these names suggest about the evolutionary relationships between these bee species? Explain your answer.

Ecologists investigated changes in grassland communities on large islands off the coast of Scotland between 1975 and 2010. On each island, they used data from a number of sites to determine the change in mean species richness and the change in mean index of diversity.

Table 1 shows plant species recorded at one site, on one island, in 1975.

Calculate the index of diversity for this site using the formula:

Outline a method the ecologists could have used to determine the plant species richness at one site.

Some of the ecologists’ results are shown in Table 2. They carried out a statistical test to find out whether any differences between the 1975 and 2010 means were significant. The values for P that they obtained are also shown in Table 2.

Do these data show that there were any significant changes in the grassland communities on these islands? Give reasons for your answer.