Biodiversity within a community
A marine biology research team investigated the biodiversity of macroinvertebrates in three zones of a coastal estuary system undergoing adjacent land development:
- An undisturbed salt marsh
- An agricultural buffer zone (impacted by runoff)
- A restored tidal channel connecting two isolated patches of marsh
Their findings are summarized in the graph below:
Based on this study, answer the following questions:
What data would the research team need to collect to calculate Simpson's index of diversity (ddd) for the macroinvertebrates in each habitat? Do not include sampling equipment in your answer.
State two procedures the researchers should have followed to ensure that the collected samples provided a representative measure of the diversity in each zone.
Urban development and coastal agricultural expansion often fragment wetlands, increasing the relative area of agricultural buffer zones at the expense of undisturbed marshes. Use the data in the graph to suggest how this land-use change affects macroinvertebrate biodiversity.
Coastal developers are being encouraged to establish and maintain restored tidal channels connecting isolated patches of salt marsh. Suggest and explain one ecological benefit of these tidal channels and one practical or economic disadvantage to a developer of maintaining them.
Define the biological term community.
Which statement correctly describes the species richness of a community?
- The total number of individual organisms of all species in a habitat
- The number of different species in a community
- The proportion of each species relative to the total number of individuals
- The variety of abiotic factors present within a community
An agricultural researcher compared a heavily-fertilized monoculture ryegrass pasture to a restored wildflower meadow. Both areas were found to contain exactly 15 species of beetles.
Explain why calculating an index of diversity is a more useful measure of biodiversity than recording only species richness in this comparison.
A group of biology students investigated the biodiversity of ground-dwelling invertebrates in three zones of a managed forest:
- the woodland interior
- the woodland edge (near open grassland)
- a narrow woodland corridor connecting two larger blocks
Their results are shown in Figure 1 below.
Based on this study, answer the following questions:
What data would the students need to collect to calculate Simpson's index of diversity for the invertebrates in each habitat? Do not include sampling apparatus in your answer.
Give two ways the students would have ensured their calculated index of diversity was representative of each habitat.
Forest management practices sometimes result in larger forests being fragmented into smaller, isolated blocks, increasing the proportion of forest edge relative to forest interior. Use Figure 1 to suggest why invertebrate biodiversity decreases when forests are fragmented into smaller blocks.
Landowners are being encouraged to preserve and plant woodland corridors between isolated woodland blocks. Suggest and explain one ecological advantage and one practical or economic disadvantage to a developer or landowner of maintaining woodland corridors on their land.
Define the biological term community.
Which statement correctly describes the species richness of an ecosystem?
- The total number of individuals of all species present
- The number of different species present in a community
- The relative abundance of each species present
- The variety of different habitats within an ecosystem
Explain why calculating an index of diversity is a more useful measure of biodiversity than recording only species richness.
Biodiversity within a community Questions
Practise AQA A Level Biology Biodiversity within a community with exam-style questions for A Level Biology. 4 questions, matched to the AQA A Level Biology (7402) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.