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directional selection in biology short 1 sentence definition, 2 simple examples, and 1 short sentence using it 9th grade level

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Answered by GPT-5 mini AI
Definition: Directional selection is when natural selection favors individuals at one extreme of a trait, causing the population's average trait to shift in that direction over time.

Examples:
1. During the Industrial Revolution, darker peppered moths became more common in polluted forests because they were better camouflaged from predators.
2. Bacteria exposed to antibiotics evolve so that resistant strains (the extreme) become more common than non-resistant ones.

One short sentence using it: Directional selection caused the finches' beaks to get larger after a long drought.