The result of stabilizing is the over-representation in a specific trait. For example, the
coats of a species of mice in a forest will all
be the best color to act as camouflage in their environment. Other examples include human birth weight, the number of eggs a bird lays, and the density of cactus spines.
How does stabilizing selection occur?
In summary, stabilizing selection happens
when extreme phenotypes on both ends of the spectrum are unfavorable
. This type of selection leads to enrichment of intermediate phenotypes and narrowing of the range of variation.
What causes stabilizing selection?
In that way, like all forms of selection, the cause of stabilizing selection is
the increased fitness and reproductive success that the median individuals have
. The extreme versions or traits have a disadvantage, in one way or another. This disadvantage, in evolutionary terms, is decreased reproduction.
What can cause disruptive selection?
Disruptive selection occurs when individuals
of intermediate phenotype are less fit than
those of both higher and lower phenotype, such that extremes are favored. This may occur if there are two diverse food sources or predators with diverse preferences for, say, size of prey.
Why is stabilizing selection more common?
Stabilizing selection tends
to remove the more severe phenotypes
, resulting in the reproductive success of the norm or average phenotypes. This means that most common phenotype in the population is selected for and continues to dominate in future generations.
What do stabilizing selection and directional have in common?
Stabilizing and directional selection both drive homogeneity in a specific trait, reducing diversity. In the case of stabilizing selection
any extreme variations are selected against while
in directional selection one extreme is selected for.
What is Stabilising selection a level biology?
In stabilising selection an
average phenotype is selected for and extremes of the phenotype are selected against
. In an area where trees were less dark, and where there was less light lichen, moths at either extreme of colouration would be less successfully camouflaged and would be selected against.
Could stabilizing selection lead to a new species?
Could stabilizing selection lead to the creation of a new species? Justify your
reasoning
using what you’ve learned from Model 2. no , the individuls in the species just become more alike. It’s unlikely to change the ablity to mate within the population to produce fertile offspring.
Does Stabilising selection lead to speciation?
When mating is nonselective,
stabilizing selection always prevents speciation
. The population starts splitting because of assortative mating, but after a few generations individuals with intermediate phenotype increase in frequency because of natural stabilizing selection.
Which result might be a consequence of stabilizing selection?
Stabilizing selection results in
a decrease of a population ‘s genetic variance when natural selection favors an average phenotype and selects against extreme variations
. In directional selection, a population’s genetic variance shifts toward a new phenotype when exposed to environmental changes.
What is a good example of disruptive selection?
Sometimes called Diversifying selection. This type of selection favors both the extremes at the expense of the average. An example of this is
rabbits
. In this example the rabbits have either black and white fur co-dominant genes, black fur represented by “B ? and white fur represented by “b ?.
How does disruptive selection increase genetic variation?
Under disruptive selection, individuals with extreme values for a trait have greater reproductive success than individuals with intermediate values. Because
the values for the trait in the resulting population are further from the population mean
, the variation of the trait is increased.
How do stabilizing and disruptive selection differ?
how do stabilizing and disruptive selection differ?
Stabilizing selection reduces the amount of variation in a trait
. Disruptive selection increases the amount of variation in trait.
Is stabilizing selection rare?
Stabilizing selection appears to be the more common form of
nonlinear selection
. The most common model of stabilizing selection used in evolutionary quantitative genetics is the Gaussian stabilizing selection model (56).
What does it mean stabilizing?
1 : to make stable, steadfast, or firm. 2 : to
hold steady
: such as. a : to maintain the stability of (something, such as an airplane) by means of a stabilizer. b : to limit fluctuations of stabilize prices.
Does stabilizing selection increase fitness?
Natural selection on polygenic traits can take the form of: Stabilizing selection:
Intermediate phenotypes have the highest fitness
, and the bell curve tends to narrow. Directional selection: One of the extreme phenotypes has the highest fitness. The bell curve shifts towards the more fit phenotype.
How does Diploidy preserve genetic variation?
How does diploidy help to preserve genetic variation? It allows recessive alleles that may not be favored in the current environment to be preserved in the
gene pool by propagation of heterozygotes
. … The ultimate source of new alleles are mutations, random changes in the nucleotide sequences of an organism’s DNA.
What are the five conditions impacting the Hardy Weinberg equilibrium?
The conditions to maintain the Hardy-Weinberg equilibrium are:
no mutation, no gene flow, large population size, random mating, and no natural selection
. The Hardy-Weinberg equilibrium can be disrupted by deviations from any of its five main underlying conditions.
Which of these occurs in a population during stabilizing selection?
In stabilizing selection, what occurs in a population?
The population shifts toward one of two extreme phenotypes
. Both extreme phenotypes shift toward the middle. The intermediate phenotype becomes more common.
What is the difference between balancing and stabilizing selection?
The key difference between stabilizing and balancing selection is that
stabilizing selection is a type of natural selection which favours average phenotypes in a population
while balancing selection is the maintenance of multiple alleles of a gene within a population in order to enhance genetic diversity.
Which is a requirement for natural selection to occur?
Four conditions are needed for natural selection to occur:
reproduction, heredity, variation in fitness or organisms
, variation in individual characters among members of the population. If they are met, natural selection automatically results.
Which type of selection maintains stable frequencies?
For example, if heterozygotes at a locus have higher fitness than homozygotes (a scenario known as heterozygote advantage or overdominance),
natural selection
will maintain multiple alleles at stable equilibrium frequencies.
How does Diploidy help to preserve genetic variation See Concept 23.4 page?
How does diploidy help to preserve genetic variation? It allows recessive alleles that may not be favored in the current environment to be preserved in
the gene pool by propagation in heterozygotes
.
Which of the following describes stabilizing selection?
Stabilizing selection is a descriptive term for
what happens to an individual trait when the extremes of the trait are selected against
. This increases the frequency of the trait in the population, and the alleles and genes which help form it.
Which of the following is an example of stabilizing selection on size?
Because most traits do not change drastically over time, stabilizing selection is considered to be the most common mechanism for natural selection. Other examples of stabilizing selection are
the birth weight of humans and the number of eggs a bird lays (clutch size)
.
In which country would you most likely find a higher incidence of lactase persistence?
High percentages of lactase persistence phenotype are found in traditionally pastoralist populations like Fulani and Bedouins. Lactase persistence is prevalent in Nguni and certain other pastoralist populations of
South Africa
as a result of the dairy they consume in their diet.
How do stabilizing and disruptive selection differ mastering bio?
Stabilizing selection reduces the amount of variation in a trait
. Disruptive selection increases the amount of variation in a trait.
What are the 3 types of natural selection?
- Stabilizing Selection.
- Directional Selection.
- Disruptive Selection.
What is the rarest distribution pattern in nature?
The rarest distribution pattern in nature is
random
.
Why are the large finches now living on the?
Why are the large finches now living on
the Galápagos Islands
different from the original source population from a nearby island? -Genetic drift occurred in the two populations. … A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island.
Which phenomenon will prevent genetic drift?
The correct answer is The
population size
is large. The genetic drift leads to the extinction of original species in a less dense population….
What is disruptive selection simple?
Disruptive selection, also called diversifying selection,
describes changes in population genetics in which extreme values for a trait are favored over intermediate values
.
Is Melanism an industrial?
industrial melanism, the darkness—of the skin, feathers, or fur—acquired by a population of animals living in
an industrial region where the environment is soot-darkened
.
What is purifying natural selection?
In natural selection, negative selection or purifying selection is
the selective removal of alleles that are deleterious
. This can result in stabilising selection through the purging of deleterious genetic polymorphisms that arise through random mutations.
Can natural selection be harmful?
If negative selection is too strong for the whole population,
extinction will occur
, unless the population is rescued in time. Extinction can occur if the negative selection considered is “hard” selection, which actually reduces the number of surviving offspring that are produced.
