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Abiotic Factors (AQA GCSE Combined Science: Trilogy: Biology): Revision Note

Exam code: 8464

Written by: Lára Marie McIvor

Reviewed by: Dr Natalie Lawrence

Updated on 23 September 2026

Types of abiotic factors

An abiotic factor is a non-living factor in the environment

Abiotic factor	Affect on community
Light intensity	Light is needed by plants for photosynthesis; more light leads to an increase in rate of photosynthesis and an increase in plant growth rate
Temperature	Affects the rate of photosynthesis in plants
Moisture levels	Plants and animals require water to survive
Soil pH and mineral content	Different species of plants are adapted to different soil pH levels and nutrient concentrations
Wind intensity and direction	Wind speed affects transpiration rate in plants; this affects the rate of photosynthesis as it ensures water and mineral ions are transported to the leaves
Carbon dioxide concentration in air	CO₂ is required for photosynthesis in plants; concentration therefore affects the rate of photosynthesis
Dissolved oxygen levels in water	Some aquatic organisms can only survive in water with high oxygen concentrations

Effect of abiotic factors

Exam questions can ask students to extract and interpret information from charts, graphs and tables relating to the effect of abiotic factors on organisms within a community

Worked Example

Plants of the same species were grown in tanks with different CO₂ levels. Their height was measured after 3 weeks and an average taken:

Bar chart showing the effect of carbon dioxide concentration on average plant height. The x-axis shows CO₂ concentration from 5% to 30%, and the y-axis shows average height of plants in cm. Average plant height increases from 10 cm at 5% CO₂ to 20 cm at 10%, 30 cm at 15%, 40 cm at 20%, 50 cm at 25% and 60 cm at 30%. — **Effect of carbon dioxide concentration on average plant height**

Use this image

What conclusion can you draw from this graph about the effect of CO₂ concentration on plant growth rate?

Explain your answer.

[3 marks]

Answer:

As CO₂ concentration increases, average plant height also increases. For example, at 5% CO₂, average plant height was 10 cm, but at 30% CO₂, average plant height was 60 cm. This shows that the higher the CO₂ concentration, the greater the plant growth rate. This is because CO₂ is used by plants for photosynthesis, which allows the plant to produce glucose for energy to grow.

Examiner Tips and Tricks

When answering questions that refer to a chart, graph or table, remember to reference specific figures from the data to support your answer, as seen in the example above.

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