IGCSE Biology glossary
Phenotype
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
The observable features of an organism that result from its genotype and its environment. For example, round seeds or brown eyes.
What to include in an exam answer
The word 'observable' (or 'physical features') is what earns the mark. In monohybrid cross answers, give phenotype ratios in words tied to the trait (3 round: 1 wrinkled), not just 3:1.
Example in context
Giving a cross outcome: 'The phenotype ratio is 3 tall: 1 short, because the dominant allele is expressed whenever at least one copy is present.'
Related syllabus topic
Inheritance