Phenotype: GCSE Biology Definition

Emma Archbold

Written by: Emma Archbold

Reviewed by: Naomi Holyoak

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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

You can explore phenotype further using our GCSE revision notes, topic questions and flashcards for your specific exam board:

Meet all your GCSE biology revision needs using our revision resources linked below. This includes revision notes, videos, flashcards and exam questions with student-friendly mark schemes.

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Emma Archbold

Author: Emma Archbold

Expertise: Biology

Prior to working at SME, Emma was a Biology teacher for 5 years. During those years she taught three different GCSE exam boards and two A-Level exam boards, gaining a wide range of teaching expertise in the subject. Emma particularly enjoys learning about ecology and conservation. Emma is passionate about making her students achieve the highest possible grades in their exams by creating amazing revision resources!

Naomi Holyoak

Author: Naomi Holyoak

Expertise: Biology

Naomi graduated from the University of Oxford with a degree in Biological Sciences. She has 8 years of classroom experience teaching Key Stage 3 up to A-Level biology, and is currently a tutor and A-Level examiner. Naomi especially enjoys creating resources that enable students to build a solid understanding of subject content, while also connecting their knowledge with biology’s exciting, real-world applications.

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