Book Definition: An organism's observable physical characteristics.


A phenotype (from Greek phainein, 'to show' + typos, 'type') is the composite of an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, phenology, behavior, and products of behavior (such as a bird's nest). Phenotypes result from the expression of an organism's genes as well as the influence of environmental factors and the interactions between the two.

In Your Own Words

  • Visible characteristics, such as eye color, skin color, hair color, etc.
  • Think of PHENOTYPE and PHYSICAL TRAITS. PT and PT. This will help you distinguish the difference.
  • What you can see on the outside.


  • Having freckles.
  • Having a dimple.
  • Skin tone, height, and shoe size.
  • Your Blood type.
  • Formation of toes, eye color, and hair color.
  • An example would be a birth defect caused by medical care.
  • A persons behavior

Practice Questions

1. Which of the following is an example of a phenotype?

A. Sally likes music
B. Sally is smart
C. Sally has a dimple on her right cheek
D. Sally inherited health conditions

2. What is the definition of phenotype?

A. Your genetic makeup
B. Your secret talent
C. Your personality type
D. Your visible characteristics and traits
E. A gene that determines risk for cancer

3. Which of the following is not an example of a phenotype?

A. Blonde Hair
B. Blue Eyes
C. Cancer
D. Big Lips
E. Pointy Nose

4. Blonde hair is an example of

A. Phenotype

Answers: 1.C 2.D 3.C 4.A

Additional Resources