An example of a population of finches on a mainland having genetic stabilizing selection involves clutch size and variation in beak size.
David Lack studied a small in 1947.
Birds that lay too many eggs per nest are more likely to migrate to an island where the seeds are stable.
Birds have lower fitness values than those that lay an intermediate number.
Many offspring die due to inadequate crack open the larger seeds when a bird lays too many eggs.
In addition, the strain on the parents themselves the course of many generations will result in a may decrease their likelihood of survival and consequently their ability population of finches carrying alleles that promote larger beak size.
A new not contributing many individuals to the next generation is a way that directional selection may arise.
The most successful parents are those that produce an intermediate clutch new allele, which may confer a higher fitness in individuals that carry it size.
The mouse has dark brown fur.
The dark brown individuals mouse is more fit than the light colored mice.
Number of mice are more likely to survive and reproduce.
The highest fitness in the population's environment is determined by the pattern of natural selection.
There is a population of mice with a dark fur.
Mouse with darker fur are more likely to survive and reproduce.
Individuals with darker fur are more likely to be chosen over others.
The change in fur color is shown in the graphs.
Suppose the climate on an island changed so that the average temperature went up.
The climate change is irreversible.
The people with intermediate traits are the most fit.
The results of stabilizing selection on clutch size are shown in the graphs.
The fitness values of a particular genotype are higher in one environment and lower in another.
cies are more likely to survive in different environmental conditions
Number of individuals metal-resistant alleles are likely to be carried by plants on contaminated soil.
This pattern of natural selection selects for two different phenotypes, each of which is most Population after fit in a particular environment.
The colonial bentgrass (Agrostis capillaris) has metal-resistant alleles that allow it to grow on contaminated soil.
The grass doesn't show metal tolerance in uncontaminated soils.
Heterogeneous environments have led to the existence of metal-resistant and metal-sensitive alleles in the population.
The graphs show the change in the bentgrass population before and after selection.
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