AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Variation: the conditions in which they have developed (environmental causes)
Environmental variation is caused by the conditions in which an organism develops.
- 2 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Environmental variation is caused by the conditions in which an organism develops. These conditions include diet, temperature, light, water, minerals, exercise and accidents. For example, a plant grown in dim light may be tall and thin, while a plant of the same species grown in bright light may be short and bushy. A person's body mass can be affected by diet and exercise, and a scar is caused by an accident rather than by genes. Some characteristics, such as height or body mass, are affected by both genes and the environment. Environmental causes do not change the alleles an organism inherits, so they are not passed on to offspring in the same way as genetic variation.
What earns the marks
- Environmental variation is caused by the conditions in which an organism develops.
- Examples of environmental factors include diet, temperature, light, water, minerals, exercise and accidents.
- Environmental factors can change characteristics such as height, body mass, leaf size or scar formation.
- Some characteristics are affected by both genetic and environmental causes.
- Environmental causes do not change the alleles inherited by an organism.
- Identical genotypes can produce different phenotypes in different environments.
Common mistakes and how to put them right
Writing that environmental factors change genes or alleles.
Put it right: They affect how an organism develops but do not alter the inherited alleles.
Giving only one environmental factor, such as diet, when a question asks for environmental causes generally.
Put it right: Include a range of factors.
Confusing a characteristic that is mainly genetic, such as blood group, with one that is strongly affected by the environment, such as body mass.
Exam tips
- Name the environmental factor and state the effect it has on the characteristic.
- Use a clear example, such as a plant in dim light growing tall and thin, to show understanding.
- If a characteristic has both causes, mention the inherited alleles and the environmental factor.
Try the lesson
The start of the Variation: the conditions in which they have developed (environmental causes) lesson, made from checked teaching notes for this specification point.
Have a go first
Which of these is an environmental cause of variation in a plant?
Listen
Environmental variation is caused by the conditions in which an organism develops. These conditions include diet, temperature, light, water, minerals, exercise and accidents. For example, a plant grown in dim light may be tall and thin, while a plant of the same species grown in bright light may be short and bushy. A person's body mass can be affected by diet and exercise, and a scar is caused by an accident rather than by genes. Some characteristics, such as height or body mass, are affected by both genes and the environment. Environmental causes do not change the alleles an organism inherits, so they are not passed on to offspring in the same way as genetic variation. A strong answer earns marks for these points. Environmental variation is caused by the conditions in which an organism develops. Examples of environmental factors include diet, temperature, light, water, minerals, exercise and accidents. Environmental factors can change characteristics such as height, body mass, leaf size or scar formation. Some characteristics are affected by both genetic and environmental causes. Exam tip: Name the environmental factor and state the effect it has on the characteristic.
Key words
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Environmental variation
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Interaction of genes and environment
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See every definition
- Environmental variation
- Caused by the conditions in which an organism develops, including diet, temperature, light, water, minerals, exercise and accidents.
- Interaction of genes and environment
- Some characteristics, such as height or body mass, are affected by both genes and the environment.
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