What does selection advantage mean

For example, the peacock has a magnificent long tail to attract mates, giving them a reproductive advantage. The moths that camouflage to the bark of the tree to avoid predators and able to reproduce, give moths a survival advantage. For plants, they increase their spectrum of potential pollinators, giving plants a reproductive advantage. There are factors in reproductive advantage to consider such, as mate choice and sexual selection, which is why reproductive advantage is different from fitness.

Parental care is also a factor since taking better care of offspring often gives an advantage in later life. However, it is quantified over generations, since organisms negate the effects of the variation in a single year or breeding season. What are the four principles of evolution? How are these principles being carried out in natural selection?

The four principles of evolution by Charles Darwin are presented below. Competition : Each generation produces more individuals in a given environment. These individuals, however, compete with each other for natural resources.

Resources that make them survive and have a chance to pass on their genes to the next generation. Moreover, competition can either be intraspecific or interspecific. Intraspecific competition occurs among members of the same species.

For example, two lizards of the same species compete for mates in the same area. This kind of competition is the common factor of natural selection that leads an organism to have better adaptation in the population. Another type is interspecific competition in which members of two different species compete.

For example, predators of different species, in the same area compete for the same prey. This type of competition may lead the other species to go extinct. If that species is less adapted and gets fewer resources that the two different species need. Heritable differences : Genetic or trait differences can be found within the individual in the population. These differences are apparent as both visible or invisible traits that can be beneficial or not.

The variation then is preferred and essential, as it will provide a higher chance of species survival. Moreover, heritability is a concept that entails how much variation in a given trait is qualified for genetic variation.

It is said to be specific from one population in the same environment and changed over time as circumstances change. Like for example, the melanism of the peppered moth in England.

Industrialization produces air pollution to the area, soot from factories makes the tree darker. We know that formerly the peppered moth has a light color to blend the bark of the tree and lichens. In this case, dark moths became abundant than the light moths as the latter became vulnerable to predators. Survival of the Fittest : Genetic variance of an individual tends to be well-suited to their environment for survival and reproduction.

Fitness refers to advantageous traits- endurance, strength, speed, social skills, intelligence, etc. Though forces affecting survival were not equally the same on individuals, there were always variations. These variations would confer fitness over the others. We looked again at the example of peppered moths; the dark moth becomes more fit to the changing environment. As the dark moth fitness increased, it was able to survive and reproduce.

While light moths decrease in numbers, fitness is not favorable for them. Fitness denotes survival and reproduction in a specific environment.

Descent with Modification : A formation of a new species from a common ancestor due to reproductive isolation. There is a diversion of genetic characteristics that allow organisms to emerge distinctly from a common ancestor. For example, a population of tortoises on Galapagos island has a longer neck than those tortoises that live on dry lowlands.

The long-necked tortoises are selected because they could reach more leaves and access better food. When drought occurs, fewer leaves will be available in the islands. Those that can grasp more leaves have a better chance to survive than those who could not reach the leaves. As a result, long-necked tortoises are more likely to be reproductively successful.

By then, the long-necked trait will be passed on, to their offspring. In time, only long-necked tortoises will be available in the population. Because traits are inherited, these traits will be represented in the next generation. It will then lead to change in a population over generations through a process called descent with modification.

It happens when natural selection favors the intermediate states of character against the extreme character variation to survive.

Like for example, the height of the plants, the small plant received less sunlight compared to the tall plant. However, tall plants are vulnerable to wind disruption. Given these two pressures, the plant will maintain at medium height. Over time small plants and tall plants decrease in number while the medium plants continue to increase. In this scenario, the plants undergo stabilizing selection.

The plant diversity decreases as the population stabilizes on a particular trait value- the medium plants. This type of selection pushes the trait towards the average instead of extremes. Simply, stated that the cause of stabilizing selections increased the reproductive success that the median individual has. These extreme traits have a disadvantage in one way or another, thus decreased reproduction.

In directional selection, it occurs when a single phenotype favored, causing the frequency to shift into one direction. The population trait distribution will change toward the other extreme trait. In this case, a classic example is a peppered moth in England.

Before the industrial revolution, peppered moths are naturally light in color to blend in light-colored trees and lichens.

However, when air pollution from the industries makes trees darker in color. The light-colored moths on darkened trees become vulnerable for predators to spot. Peppered moths shift over time to become darker in color to camouflage dark-colored trees. The number of darker moths increases as they have a higher survival rate in habitats affected by air pollution.

When the environment changes often, the population undergoes directional selection. Thus, there is a shift of population genetic variance towards new fit phenotypic variance. When the characteristic falls at one end, and, the other phenotypic spectrum favored over the others, the selection is directional. This type of selection removes an individual from the center of a phenotypic distribution. It occurs when natural selection favors both extreme continuous variations.

In this selection, the distribution becomes bimodal. Two extreme variations will become more common that eventually lead to two new distinct species. Like for example, coloration allows an organism to match or blend its background to prevent recognition from predators. In the case of oysters, light-colored oysters are more hidden than intermediate-colored oysters.

Dark-colored oysters, on the other hand, blend into the shadows of the rocks. Hence, intermediate-colored oysters are more vulnerable to be eaten by the crabs. The light-colored and dark-colored oysters will survive and reproduce. This type of selection that produces more variations is called polymorphism.

The organism that is more capable of securing mates is said to be more fitted to the environment. The existence of a particular trait among members of one sex can somehow gain attraction to the opposite sex. Like for example, in Drosophila flies, some of them have yellow body coloration as a result of spontaneous mutation.

In contrast, others have normal yellowish-gray pigmentation. Yellowish gray coloration male is more preferred than yellow-colored males by female flies. Another example is the stags male deer. The antlers of stags increase prowess in competition. Thus, in a contest of strength, those with better antlers have the advantage of winning and securing a mate. Thus, sexual selection leads to increased size and aggressiveness in males.

The ultimate goal of sexual selection is to reproduce in which an individual needs to maximize the ability to obtain a mate and produce viable offspring. Sexual selection is also referred to as nonrandom differential reproduction as a result of differential access to mate and reproductive labors. Like for example, the peacock tail, when sexual selection favors the evolution of conspicuous courtship structures, then it enhances mating success.

This type of natural selection is an interaction between organisms in which the predator captures and eats the part or whole body of the other organism-the prey.

Predators and prey often have advantageous traits arising from natural selection that help them perform better in the environment. Like for instance, prey has a defense adaptation to escape from predators. These defenses vary in nature, might be chemical, mechanical, and behavioral.

For example, the millipede has both chemical and body defense. It produces noxious substance and curls into a defensive ball when threatened.

Many organisms used their coloration or body shape to avoid predators. For example, the chameleon changes color to blend its surroundings. Over time the process of natural selection can change the organism to make them better predators and more defensive prey. Either way, adaptation changes the entire predator-prey dynamic. If an organism cannot adapt with an appropriate defense, it may somehow go extinct. This type of natural selection involves altruistic behavior. Kin selection occurs when natural selection favors traits or character that benefits related members of the groups.

For instance, worker bees show altruistic behavior by spending their lives working the hive but never have an opportunity to reproduce on their own. However, all bees in the hives are close relatives. The traits of the worker bees will be passed on to the next generation indirectly through the queen. So, the queen produced more related offspring resulting in higher fitness of the worker bee even though it never reproduces directly.

It appears that worker behavior would not be promoted or maintained by natural selection. Because any factor causing such behavior seems likely to be eliminated from the population. Since it is not from worker bees differential reproductive success but that of the queen.

What are some examples of natural selection? View all related items in Oxford Reference ». Search for: 'selective advantage' in Oxford Reference ». All Rights Reserved.

Under the terms of the licence agreement, an individual user may print out a PDF of a single entry from a reference work in OR for personal use for details see Privacy Policy and Legal Notice. Oxford Reference. Publications Pages Publications Pages. Recently viewed 0 Save Search. Your current browser may not support copying via this button. Subscriber sign in You could not be signed in, please check and try again. This type of natural selection occurs when selective pressures are working in favour of one extreme of a trait.

Therefore when looking at a distribution of traits in a population, a graph tends to lean more to one side:. Example: Giraffes with the longest necks are able to reach more leaves to each.

Selective pressures will work in the advantage of the longer neck giraffes and therefore the distribution of the trait within the population will shift towards the longer neck trait. This type of natural selection occurs when selective pressures are working in favour of the two extremes and against the intermediate trait. This type of selection is not as common. When looking at a trait distribution, there are two higher peaks on both ends with a minimum in the middle as such:.

Example: An area that has black, white and grey bunnies contains both black and white rocks. Both the traits for white and black will be favored by natural selection since they both prove useful for camouflage.

The intermediate trait of grey does not prove as useful and therefore selective pressures act against the trait. Sch oolTutoring Academy is the premier educational services company for K and college students. We offer tutoring programs for students in K, AP classes, and college. To learn more about how we help parents and students in Hastings, Nebraska visit: Tutoring in Hastings, Nebraska.

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