Intensity of Selection: Definition

Correct Answer: Intensity of Selection

From the notes: Intensity of selection (i) = Selection differential (S) ÷ Phenotypic standard deviation (σP).

Key Formulae (from notes)

• i = S / σP
• S = i × σP
• Response to selection: R = h²S = i·h²·σP = i·σA·rAP

Factors Affecting Intensity of Selection (from notes)

1. Proportion of population selected (fewer animals selected → higher intensity)
2. Phenotypic standard deviation (σP)
3. Sex of animal under selection
4. Number of traits under selection
5. Accurate measurement of the trait

Factors Affecting Response to Selection (from notes)

1. Intensity of selection (i)
2. Additive genetic variance (σA)
3. Accuracy of selection (rAP)
4. Population size
5. Generation interval