A population will not exist in Hardly-Weinberg equilbrium if

Options

A. there are no mutation
B. there is no migration
C. the population is large
D. individuals mate selectively

Answer

### Step-by-Step Solution:

1. **Understanding Hardy-Weinberg Equilibrium**: The Hardy-Weinberg principle states that allele frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences. This is known as genetic equilibrium.

2. **Conditions for Hardy-Weinberg Equilibrium**: There are five main conditions that must be met for a population to be in Hardy-Weinberg equilibrium:
- No mutations
- Random mating
- No gene flow (migration)
- Large population size (to prevent genetic drift)
- No natural selection

3. **Identifying Factors that Disrupt Equilibrium**: A population will not exist in Hardy-Weinberg equilibrium if any of the above conditions are violated. Specifically, if there is:
- **Mutation**: Changes in the genetic material can alter allele frequencies.
- **Non-random mating**: If individuals select mates based on certain traits, this can affect allele frequencies.
- **Migration**: Movement of individuals into or out of the population can introduce new alleles or remove existing ones.
- **Small population size**: In smaller populations, random events can have a larger impact on allele frequencies (genetic drift).
- **Natural selection**: If certain traits confer a survival advantage, those alleles will increase in frequency over time.

4. **Conclusion**: Based on the conditions listed, the population will not exist in Hardy-Weinberg equilibrium if individuals mate selectively. This violates the condition of random mating, which is essential for maintaining constant allele frequencies.

### Final Answer:
A population will not exist in Hardy-Weinberg equilibrium if individuals mate selectively.

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