Examkin

Question

Difficulty: EasyContinuous and Discontinuous Variation

During a biology practical session, students recorded various inherited characteristics in their peer group. Which of the following traits demonstrates discontinuous variation?

  1. A
    Height
  2. ABO blood groupAnswer
  3. C
    Body weight
  4. D
    Skin color

Answer

ABO blood group
ABO blood group exhibits discontinuous variation because individuals fall into clear-cut, distinct phenotypic categories (A, B, AB, and O) without intermediate phenotypes, and the trait is strictly inherited without environmental modification.

Step-by-Step Solution

1
Identify the distinguishing characteristic of discontinuous variation.
Discontinuous variation produces distinct, non-overlapping phenotypic categories without intermediate forms, usually under monogenic control.
Qualitative traits are determined by major alleles at one or very few gene loci.
2
Evaluate the phenotypic distribution of each listed trait.
Height, body weight, and skin color display continuous gradations across a population spectrum. In contrast, ABO blood group classifies individuals strictly into discrete groups (A, B, AB, or O).
Blood groups show clear-cut phenotypic distinction unaffected by environmental factors.

Key Concept

Discontinuous phenotypic variation in human traits
Estimated Time:45s
Rate this question

Topics

Continuous and Discontinuous Variation

More questions from this topic