Abiotic and Biotic Factors
Get to grips with Abiotic and Biotic Factors for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Abiotic factors are non-living, such as light, temperature and water, while biotic factors are living, such as predators, food and disease.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Organisms are affected by two kinds of environmental factor. Abiotic factors are non-living; biotic factors are living.
Abiotic factors include light intensity, temperature, moisture levels, soil pH and mineral content, wind intensity and direction, carbon dioxide levels for plants, and oxygen levels for aquatic animals. Each affects how well an organism can survive in a habitat.
Biotic factors include the availability of food, new predators arriving, new pathogens, and competition between species where one may outcompete another so numbers fall. A change in either type of factor can affect the size of a population.
Revision notes
Abiotic factors
Light intensity, temperature, moisture levels, soil pH and mineral content, wind intensity and direction.
Carbon dioxide levels affect plants, and oxygen levels affect aquatic animals. All are non-living components of the environment.
Biotic factors
Availability of food, new predators arriving, new pathogens, and competition.
If one species outcompetes another so that its numbers are no longer sufficient to breed, that species may die out in the habitat.
Effects on populations
A change in an abiotic factor such as a drought reduces water availability, so plant numbers fall and animals dependent on them decline too.
A change in a biotic factor such as a new predator reduces prey numbers. Either can destabilise a community.
Key points
- Abiotic factors are non-living.
- Abiotic factors include light, temperature and moisture.
- Soil pH and mineral content are abiotic.
- Biotic factors are living.
- Biotic factors include food availability and predators.
- Competition is a biotic factor.
Worked examples
Example 1
Give three abiotic factors that affect a community. [3 marks]
Model answer
Light intensity (1 mark), temperature (1 mark), and moisture levels or soil pH (1 mark).
Example 2
Explain the difference between an abiotic and a biotic factor. [2 marks]
Model answer
An abiotic factor is a non-living component of the environment, such as temperature or light intensity (1 mark). A biotic factor is a living component, such as the availability of food or the presence of predators (1 mark).
Example 3
Explain how the arrival of a new predator could affect a community. [2 marks]
Model answer
The new predator would eat the prey species, so the prey population would fall (1 mark). Other species that depend on that prey for food would then also decline, affecting the whole community (1 mark).
Common mistakes
Calling competition an abiotic factor.
Competition involves living organisms, so it is biotic.
Saying carbon dioxide affects all organisms equally.
It is listed as affecting plants; oxygen levels affect aquatic animals.
Giving only one type of factor.
Questions often want both abiotic and biotic examples.
Confusing abiotic and biotic.
Abiotic means non-living; biotic means living. The a- prefix means without.
Exam tips
- Remember abiotic means non-living and biotic means living.
- Learn several examples of each.
- Explain effects through a chain: factor changes, population changes, community changes.
- Give the number of factors the marks require.
Key terms
- Abiotic
- A non-living environmental factor.
- Biotic
- A living environmental factor.
- Habitat
- The place where an organism lives.
- Population
- All the individuals of one species in an area.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.