What mistakes do students make with Biodiversity within a community?

Generalising from one sampled site to a whole river, region or country without saying that the data may not be representative. Giving two conservation reasons that are really the same point, such as 'protects animals' and 'protects species'. Using biodiversity and species richness as interchangeable words when the question distinguishes them.

What are the exam tips for Biodiversity within a community in Biology AQA A-Level?

In any evaluate question about biodiversity data, check three things: how many sites, over what period, and against what control or comparison. State the habitat and the scale in your first sentence so the rest of your answer stays anchored to it. For 'suggest two reasons' questions, make the two reasons clearly different ideas, because near-duplicates score once.

AQA · A-Level · Biology

Course version: 7402 · Version from Sept 2016

Biodiversity can relate to a range of habitats, from a small local habitat…

Full specification wording

Biodiversity within a community: Biodiversity can relate to a range of habitats, from a small local habitat to the Earth.

Biodiversity is the variety of living organisms in an area, and the area can be any size: a single pond, a hedgerow, a stretch of river downstream of a power station, a rainforest, or the whole…

Checked against the AQA 7402 specification (opens in a new tab) on 19 September 2026.

Point 1 of 4
2 key terms

Study notes

From the checked teaching notes for this specification point.

The idea

What earns the marks

Stating the scale of habitat the biodiversity figure refers to, from a single site to the whole Earth.
Criticising a conclusion because the data come from only one site or community and may not be representative.
Criticising a conclusion because sampling took place at only one time of year, when the community may differ at other times.
Distinguishing species richness from genetic diversity when a question asks which level of biodiversity a figure measures.
Explaining that a larger habitat can support more species or more niches, so its biodiversity is likely to be greater.

Common mistakes and how to put them right

Generalising from one sampled site to a whole river, region or country without saying that the data may not be representative.
Giving two conservation reasons that are really the same point, such as 'protects animals' and 'protects species'.
Using biodiversity and species richness as interchangeable words when the question distinguishes them.
Forgetting that sampling in a single month may miss seasonal species, which is a routinely credited evaluation point.
Answering a conservation question with economic reasons only when the marks are for biological ones.

Exam tips

In any evaluate question about biodiversity data, check three things: how many sites, over what period, and against what control or comparison.
State the habitat and the scale in your first sentence so the rest of your answer stays anchored to it.
For 'suggest two reasons' questions, make the two reasons clearly different ideas, because near-duplicates score once.

Try the lesson

The start of the Biodiversity within a community: Biodiversity can relate to a range of habitats, from a small local habitat to the Earth. lesson, made from checked teaching notes for this specification point.

Have a go first

Biodiversity can be assessed at various scales, from a small local habitat to the entire Earth. When comparing the biodiversity of a single garden pond to the global biodiversity of freshwater ecosystems, which statement is correct?

Tip: press 1 to 4 to choose

Listen

Biodiversity is the variety of living organisms in an area, and the area can be any size: a single pond, a hedgerow, a stretch of river downstream of a power station, a rainforest, or the whole planet. The scale has to be stated, because a measurement made in one place does not describe another. That is the basis of a standard exam criticism: data collected at one site, or in one month, describe that community at that time and cannot be generalised to all communities or to the whole year. Biodiversity is also measured at more than one level, including the number of species in a community, the genetic variety within a species, and the range of habitats present, and questions often turn on which level a given figure actually measures. A strong answer earns marks for these points. stating the scale of habitat the biodiversity figure refers to, from a single site to the whole Earth. criticising a conclusion because the data come from only one site or community and may not be representative. criticising a conclusion because sampling took place at only one time of year, when the community may differ at other times. distinguishing species richness from genetic diversity when a question asks which level of biodiversity a figure measures. Exam tip: In any evaluate question about biodiversity data, check three things: how many sites, over what period, and against what control or comparison.

See it

A top-down flowchart starting from a node reading 'Biodiversity: variety of living organisms in an area'. This branches into three parts. The first branch is 'Scale of habitat must be stated', which leads to two nodes: 'Small local habitat' and 'Whole Earth'. The second branch is 'Levels of biodiversity', leading to three nodes: 'Number of species in a community', 'Genetic variety within a species' and 'Range of habitats present'. The third branch is 'Limits on conclusions', leading to two nodes: 'Data from one site may not be representative' and 'Sampling at one time of year may miss seasonal species'. — It shows that biodiversity applies at any habitat scale, is measured at several levels, and that conclusions are limited by single-site or single-time sampling.

Key words

Say what each word means before you turn the card.

scale of biodiversity

Try answering aloud or in your head before turning the card.

levels of biodiversity

Try answering aloud or in your head before turning the card.

See every definition

scale of biodiversity: The range of habitats a biodiversity figure relates to, from a small local habitat to the Earth, which has to be stated.
levels of biodiversity: Biodiversity is measured at more than one level, including the number of species in a community, the genetic variety within a species, and the range of habitats present.

Label the diagram

Some boxes have lost their names. Pick the right name for each number.

The diagram again, with 3 boxes numbered instead of named. A top-down flowchart starting from a node reading 'Biodiversity: variety of living organisms in an area'. This branches into three parts. The first branch is 'Scale of habitat must be stated', which leads to two nodes: 'Small local habitat' and 'Whole Earth'. The second branch is 'Levels of biodiversity', leading to three nodes: 'Number of species in a community', 'Genetic variety within a species' and 'Range of habitats present'. The third branch is 'Limits on conclusions', leading to two nodes: 'Data from one site may not be representative' and 'Sampling at one time of year may miss seasonal species'.

1Box 1
2Box 2
3Box 3

0 of 3 labelled

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