Phenotype - GCSE Biology Definition
Reviewed by: Emma Archbold
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What is phenotype?
In GCSE biology, phenotype can be defined as the observable characteristics of an organism. This can be an organism’s external characteristics, such as eye colour, or internal characteristics, such as blood type.
For most characteristics, the phenotype of an organism is determined by a combination of genetic and environmental factors:
phenotype = genotype + environment
The interaction between genetics and environment can be seen in an individual’s height; genetic factors influence how tall an individual can become, but environmental factors, such as childhood diet, are also significant.
Some phenotypic characteristics are determined by genetic factors alone, e.g. blood type, and some are determined by environmental factors alone, e.g. scarring.
Phenotype revision resources to ace your exams
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