(g) the ecological, economic and aesthetic reasons for maintaining…

The idea

Biodiversity is maintained for three overlapping kinds of reason, and a multiple-choice question will test whether you can classify a given example correctly. Ecological reasons concern the functioning of ecosystems: diverse communities tend to be more stable and resilient, and the organisms within them provide services such as pollination, nutrient cycling, soil formation and flood regulation. Economic reasons concern direct and indirect value to people: medicines derived from wild species, food crops and their wild relatives, timber, fisheries, tourism and the insurance value of genetic diversity against future disease or climate change. Aesthetic reasons concern cultural, recreational and intrinsic value: landscapes people value, wildlife watching, and the ethical view that species have worth beyond human use.

What earns the marks

• Ecological reasons: maintaining biodiversity supports ecosystem stability and resilience, so communities recover better from disturbance.
• Ecological reasons: diverse communities sustain services such as pollination, nutrient cycling and soil formation.
• Economic reasons: wild species and genetic diversity underpin medicines, crops, timber, fisheries and tourism.
• Economic reasons: genetic diversity acts as insurance against future pests, disease and environmental change.
• Aesthetic reasons: biodiversity has cultural, recreational and intrinsic value independent of direct use.
• Distinguish reasons for maintaining biodiversity from methods of maintaining it, which are a separate specification point.

Common mistakes and how to put them right

• Confusing a method (such as a nature reserve or a seed bank) with a reason for maintaining biodiversity.

  Put it right: A reason explains why biodiversity matters, a method explains how it is conserved.

• Treating aesthetic value as unimportant or non-scientific.

  Put it right: Cultural, recreational and intrinsic value are recognised aesthetic reasons in the specification.

• Assuming all economic value is from harvesting organisms.

  Put it right: Indirect value such as tourism and ecosystem services also counts as economic.

Exam tips

• Read the stem to see whether it asks for a reason or a method before choosing an option.
• Classify each option as ecological, economic or aesthetic, then match it to the stem.
• Eliminate options that describe conservation techniques rather than benefits of biodiversity.