Stabilizing selection

This is thought to be the most common mechanism of action for natural selection because most traits do not appear to change drastically over time.

[4] This means that most common phenotype in the population is selected for and continues to dominate in future generations.

In order for a population to adapt to changing environmental conditions they must have enough genetic diversity to select for new traits as they become favorable.

The fourth type of data is DNA sequences from the genes contributing to observes phenotypic differences.

They can involve studying the changes that causes natural selection in the mean and variance of the trait, or measuring fitness for a range of different phenotypes under natural conditions and examining the relationship between these fitness measurements and the trait value, but analysis and interpretation of the results is not straightforward.

However, most quantitative traits (height, birthweight, schizophrenia) are thought to be under stabilizing selection, due to their polygenicity and the distribution of the phenotypes throughout human populations.

1: directional selection : a single extreme phenotype favoured.
2, stabilizing selection : intermediate favoured over extremes.
3: disruptive selection: extremes favoured over intermediate.
X-axis: phenotypic trait
Y-axis: number of organisms
Group A: original population
Group B: after selection
Depending on the environmental conditions, a grey wolf may have an advantage over wolves with other variations of fur color. Wolves with fur colors that do not camouflage appropriately with the environmental conditions will be spotted more easily by the deer, resulting in them not being able to sneak up on the deer (leading to natural selection).
Bicyclus anynana with wing eyespot, which experiences stabilizing selection to avoid predation.
The Siberian husky experiences stabilizing selection in terms of their leg muscles, allowing them to be strong but light.