What type of selection occurs when individuals in a population?

What type of selection occurs when individuals in a population?

The intermediate phenotype is preferred and becomes more prevalent in the population under stabilizing selection. Disruptive selection occurs when individuals with extreme phenotypes are preferred while others with intermediate phenotypes are chosen against by nature. This creates diversity in the population.

Stabilizing selection keeps a trait near its optimal value by choosing individuals with intermediate values for that trait. If the selective pressure is strong enough, the trait will be fixed for these intermediates. Disruptive selection removes individuals with traits far outside the norm for their population, so that new variants cannot appear in the population. This process can result in evolutionary change very quickly.

Natural selection is the main driver of evolution. It acts on phenotypes that provide an advantage in terms of survival or reproduction. These advantages could be achieved through better defense against natural predators or competition for food or mates. Natural selection can also act on behaviors such as protective measures taken against heat or cold, or techniques used to find food or avoid being eaten. It can select for or against differences between body parts: individuals with adaptations for survival in predator-rich environments tend to have larger brains and teeth than those who do not need to worry about danger from without. Selection can also act on characteristics hidden from view, such as hormones or enzymes produced by cells.

What type of selection favors both extremes?

Selection that is disruptive Disruptive selection supports both extreme phenotypes, as opposed to directional selection, which prefers just one extreme. Stabilizing selection favors the intermediate phenotype, resulting in a decrease in population variance over time. This is because individuals who are far apart from the mean have a lower probability of surviving to reproduce.

Disruptive selection can occur if there are beneficial mutations available in the environment that increase an individual's fitness more than their competitors' fitness. If this happens often enough, the average fitness of the population will increase, resulting in evolution toward increased fitness. There are two ways inization can increase an individual's fitness: by being better at avoiding predators or parasites, or by being stronger or faster than others in the population. If many individuals are fitting up towards either end of the spectrum, then they will be selected for and the population will evolve toward greater variability.

Stabilizing selection occurs when natural selection acts on variants that increase the average fitness of the group, but don't greatly affect each individual. Because individuals with different traits survive and reproduce, over time the population will reach an equilibrium where those with only slightly superior traits remain alive. For example, if the survival rate of individuals with red hair is not much higher than individuals with brown hair, then over time the population will contain only people with red hair.

What do stabilizing selection and disruptive selection have in common?

Variation exists in both scenarios, but the rate of variation differs. As a result, the only thing that both stabilizing and disruptive selection have in common is variance. In stabilizing selection, the variation rate is slow. As a result of disruptive selection, more phenotypic individuals are created. The rate of change in this case is high.

Which type of natural selection can result in the appearance of a new species?

Selection that is disruptive of the normal function of the gene/protein can also lead to evolutionary change. Disruptive selection occurs when an allele or genetic variant increases an individual's chance of survival and reproduces at the expense of its competitors. For example, an allele that makes its carriers resistant to malaria would be selected for if it increased the individuals' chances of surviving and reproducing compared with their susceptible counterparts. The evolution of new species can also occur as a result of disruptive selection. For example, if an allele made its carriers more likely to reproduce while reducing their odds of survival, then over time this would lead to a population composed only of individuals who were carriers of this allele. Such a population would be subject to what is known as "genetic drift", which is a random alteration in the frequency of alleles within a population caused by the fact that not all individuals in the population are genetically identical. If the rate of genetic drift is high enough, then after a very long time all members of the population will be carriers of just one allele at each locus, which would constitute a new species.

Disruption of the normal function of genes/proteins can also occur through mutation.

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Stanley Lopez

Stanley Lopez has been working in the media industry for over 10 years. He has held positions such as social media intern, newsroom assistant, and marketing director. Stanley loves his job because he gets to learn new things every day, meet new people, and help shape the world's view of events.


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