QUESTION 31 (5 marks)
A floodplain contains reed beds, open water and woodland. Surveys record 32 bird species. Within one duck species, individuals carry different alleles for bill colour.
a) Identify the three levels of biodiversity represented, linking each to one observation. [3 marks]
b) Explain why counting bird species alone cannot describe all the biodiversity of this floodplain. [2 marks]
Practice marking scheme
Answer
a) Ecosystem: the three habitat types; species: 32 bird species; genetic: bill-colour alleles within ducks. b) Species richness omits genetic and ecosystem variation.
Working
Biodiversity can be described at several levels. Distinct ecosystems contribute ecosystem diversity; the number and relative abundance of species contribute species diversity; variation in alleles within a species contributes genetic diversity. A bird-species count measures one component of species diversity and provides no direct measurement of within-species genetic diversity or the diversity of ecosystem types.
Marking criteria
- Links the different habitat types to ecosystem diversity. [1 mark]
- Links the 32 bird species to species diversity. [1 mark]
- Links within-species alleles to genetic diversity. [1 mark]
- States that a species count does not measure genetic diversity. [1 mark]
- States that a species count does not measure ecosystem diversity or species evenness. [1 mark]
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
View the QCAA syllabusCompare your working with the guide above.