Artificial selection to obtain cows yielding higher milk output represents

Options

A. Stabilizing selection as it stabilizes this character in the population.
B. Directional as it pushes the mean of the character in one direction.
C. Disruptive as it splits the population into two one yielding higher output and the other lower output
D. Stabilizing followed by disruptive as it stabilizes the population to produce higher yielding cows

Answer

**Step-by-Step Solution:**

1. **Understanding Artificial Selection**: Artificial selection is a process where humans intentionally select specific traits in organisms to enhance certain characteristics. In this case, farmers select cows that produce higher milk output.

2. **Identifying the Type of Selection**: The question asks which type of selection is represented by this process. The options include stabilizing selection, directional selection, and disruptive selection.

3. **Analyzing Stabilizing Selection**: Stabilizing selection occurs when intermediate phenotypes are favored over extreme phenotypes. This does not apply to our scenario since we are focusing on selecting for higher milk yield, which is an extreme trait.

4. **Analyzing Directional Selection**: Directional selection occurs when one extreme phenotype is favored over others, leading to a shift in the population towards that trait. In this case, selecting cows for higher milk yield represents directional selection, as we are favoring the extreme phenotype of high milk production.

5. **Analyzing Disruptive Selection**: Disruptive selection favors extreme phenotypes at both ends of the spectrum while selecting against intermediate phenotypes. This does not apply here since we are not selecting for both high and low milk producers simultaneously.

6. **Conclusion**: Based on the analysis, artificial selection for cows yielding higher milk output represents directional selection, as it favors the extreme phenotype of high milk production.

**Final Answer**: Artificial selection to obtain cows yielding higher milk output represents **directional selection**.

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