1. Directional Selection: This type of selection favors one extreme phenotype over the other extreme and the intermediate phenotypes. This results in a shift in the population's overall trait distribution towards the favored extreme.

* Example: The evolution of antibiotic resistance in bacteria. Bacteria that are resistant to a particular antibiotic are more likely to survive and reproduce, leading to a population dominated by resistant strains.

2. Stabilizing Selection: This pattern favors intermediate phenotypes and selects against extreme phenotypes at both ends of the spectrum. This leads to a reduction in variation and the maintenance of the status quo.

* Example: Human birth weight. Babies with very low or very high birth weights have higher mortality rates than those with average birth weights. This stabilizes the distribution of birth weights around the optimal range.

3. Disruptive Selection: This pattern favors both extreme phenotypes while selecting against intermediate phenotypes. This can lead to the emergence of distinct subpopulations within a species.

* Example: The beak size in Darwin's finches. During periods of drought, finches with either very small or very large beaks had a survival advantage, while those with intermediate beak sizes struggled to find food. This resulted in two distinct populations of finches with different beak sizes.

It's important to remember that these patterns are not mutually exclusive, and natural selection can act in different ways within a single population at the same time.