When one individual of a species is able to access its resources or escape predation better than another, it is has a greater chance of surviving and reproducing. This has been coined by Darwin as natural selection. Along with mutations, genetic drift, and migration, natural selection is the driving force of evolution. In some cases though, an organism may seem to have a trait that at first glance does not seem advantageous to its fitness. Fitness is an organism’s ability to survive, find a mate, and reproduce. This can often be explained be sexual selection.
Sexual selection is when a trait increases an organism’s ability to obtain or reproduce with a mate. Courtship rituals where males display their features to females are indicative of female choice or intersexual selection. The females of a species choose a mate based on a trait that they find attractive. There are also some species in which the male is the one who chooses the mate, and it is the female who has to court (Smith and Smith 2012). In some cases, a chosen trait has no other advantage for the organism, and can in fact hinder it. For example, a peacock has an extravagant tail. This tail serves no purpose in gathering food, and can be bulky and difficult for the peacock to drag around. A peahen will choose a mate with an ostentatious tail over one that is smaller because it shows to her that the male has increased fitness. Even with a cumbersome tail, he has eluded predators. Furthermore, it takes a lot of energy and resources to maintain this tail, demonstrating that he is a healthy individual with desirable genes.
There is also sexual selection in which males compete over access to females, called intrasexual selection. Male competition can be demonstrated by the e...
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...red. Certain characters, like shape or location of horns, could also be mapped on the diagram. Where these characters were mapped on the diagram would show when the trait diverged.
Based on development location of the horns, the scientists then grouped the species into five general classes. Horns that have extended from a vertex between the eyes are found on the back of the head. Other dung beetles may have horns in the middle of their head, growing out of the region between the eyes. Below this region is a broad plate at the front of the insect’s head, called the clypeus. Horns can even grow from here. The final classes of horns grow from the top part of the thorax, called the pronotum. They can come out from the center or from the sides of the beetle (Emlen et al. 2005B). In some cases, beetles would have horns in multiple locations; these can be seen in Figure 2.
Biological evolution is a change in the characteristics of living organisms over generations (Scott, 2017). A basic mechanism of evolution, the genetic drift, and mutation is natural selection. According to Darwin's theory of evolution, natural selection is a process in nature in which only the organisms best adapted to their environmental surroundings have a higher chance of surviving and transmitting their genetic characters in increasing numbers to succeeding generations while those less adapted tend to be eliminated. There has been many experimental research projects that relate to the topic of natural selection and evolution.
Evolution is the process by which organisms develop unique derived traits. Evolved traits that decrease an organism’s survival rate are selected against in a population. Traits that increase an organism’s survival rate, on the other hand, are often selected for, meaning that those traits will appear more frequently in the genetic codes of members in a population. This process of selection can take several forms, one of them called sexual selection. Sexual selection occurs when one member of a particular species selects a mate with more favorable traits than other members of their species. An example of sexual selection would be the evolution of “hairlessness” in modern humans. Modern humans do not have a single coat of undiversified hair, unlike
"Persistent female choice for a particular male trait values should erode genitive variance in male traits and thereby remove the benefits of choice, yet choice persists” (Miller, Christine and Allen Moore). This phenomenon is know as the Lek Paradox and has puzzled scientists for many years. Throughout all species there has been abundant evidence showing continuous female choice of male traits, yet there is still no definite answer as to what allows for genetic variance to be maintained, and why a specific trait never becomes fixed. Many hypotheses have been theorized and researched, all providing some explanation as to how this variance in species is maintained, from traits signaling resistance to parasites, according to Hamilton and Zuk, to the hypothesis of mutational and environmental affects. Condition-dependence can also provide information as to how the lek paradox is able to exist; this hypothesis will be looked at in this paper.
Natural selection is a theory suggesting that some genetic traits will be more common than another trait in a given environment in which the organisms live in. Natural selection is a slow and gradual process which will happen in the matter of generations of the species. The traits become less or more common depending on the environmental circumstances, in other words, selection pressure.
Females like to choose mates who have very bright colors as it is a sign of the male’s good health and vigor. The natural and sexual selection can affect populations in three ways: directional (environmental conditions change in a consistent direction; one extreme of phenotypes is favored), stabilizing (environmental conditions are relatively constant; intermediate phenotype is favored), and disruptive selection (environment has more than one type of useful resource; both extremes of phenotypes are favored). An example of directional selection is pesticide resistance since only the insects with a resistance are favored; an example of stabilizing selection is that the smallest lizards have a difficulty defending their territory whereas the largest lizards are most likely to be eaten by owls; an example of disruptive selection are the black-bellied seedcrackers since they either have a large beak (which they can use to eat had seeds), or a small beak (which allows them to eat soft seeds). Disruptive selection shows a balanced polymorphism, which is when two or more phenotypes are maintained in a
Natural and sexual selection are not random processes. If there is no difference between the individuals within the species there would be no selection. Sexual selection is related to mating, it acts on individual’s ability to obtain or successfully copulate with a partner. The idea of sexual selection was introduced by Charles Darwin in 1871; he revealed that there are organisms with traits which are not explained by the concept natural selection, for example the tail of a male peacock. His found two main ways in which sexual selection works, these are intra-sexual competition and inter-sexual selection. Intra sexual competition happens within species, usually between males. They compete against each other to be chosen as a mate by a member of opposite sex. Inter-sexual selection is choosing a mate among the members of opposite sex, usually done by females.
Social groups of primates closely relate to sexual dimorphism, because how each of their communities interact with one another plays a large role in sexual selection. Sexual selection, as Darwin stated, is a key factor and cause in the morphological dimorphism between sexes of a species. Additionally, sexual selection comes from male competition, which directly correlates to primate’s social structures. For example, genus gorilla is a part of a polygynous mating system, which consists of one male and multiple female. This creates an environment where males must compete with one another to reproduce and create offspring. Due to this competition, males must prove to be strong and attract themselves to females to ensure reproductive success. These strong male traits are favored in sexual selection, because the females are highly particular about the male they mate with, so there become specific male traits that are most desirable. Therefore, in polygynous groups, sexual dimorphism is the greatest (Frayer, Wolpoff, 1985). In comparison, a monogamous primate such as genus hylobate or gibbons has a social structure that consists of a more nuclear based family. There is a lot less male competition because males do not mate with multiple females. Therefore, primates are less dimorphic in monogamous social structures (Frayer, Wolpoff,
The two books examined in this paper, Martin Daly and Margo Wilson's Homicide and David M. Buss's The Evolution of Desire, suggest that human mating strategies have an evolutionary basis. The book written by Martin Daly and Margo Wilson supplies the theoretical groundwork and the book written by David M. Buss gives validity and empirical support for the theory. The two books make a strong scientific argument for evolutionary adaptations as the most crucial element to understanding human sexuality and desire. According to this argument, the key to understanding human sexuality lies in the evolutionary origin of our species.
In To Kill a Mockingbird by Harper Lee, Atticus Finch says, "Shoot all the bluejays you want, if you can hit em', but remember it's a sin To Kill a Mockingbird." This quote demonstrates Atticus's firm belioef in the Golden Rule. The Golden Rule is to treat others how you want to be treated. Atticus follows the Golden Rule throughout the novel, including while defending Tom Robinson, a local African American accused of raping Mayella Ewell. Due to Atticus's firm belief in the Golden Rule and the fact he must live with himself before others and tries to teach his children the right thing to do, it makes sense for him to defend Tom Robinson.
In order to understand the present lifestyles relating to different approaches and tactics applied by humans in mate choice preferences, there is the need to refer to Darwin (1859, 1871) evolutionary perspectives. Darwin (1871) sexual selection is the driving force for males and females reproductive quest for their genes survival. These driving forces have been classified into two categories as intra-sexual and intersexual mate selection.Intersexual selection is male sexual selection process whereby males compete with other males and the females choose the strongest as their ideal partner. Intra-sexual selection occurs when the male species fight among themselves and the strongest gain access to females for
The traditional explication for the maintenance of sex was that the process of meiosis and fertilization engender genetic variation on which natural cull can act.
Darwin states that this struggle need not be competitive in nature and also entails a species’ efficiency at producing offspring. Natural selection works not as an active entity that seeks and exterminates species that are not suited for their environment; instead, it retains variations that heighten a species’ ability to dominate in the struggle for existence and discards those that are detrimental or useless to that species. Stephen J. Gould explains the case of r-selection in which a species’ chances of survival are most reliant on its ability to reproduce rapidly and not on its structure being ideally suited for its environment. Gould’s example shows the beneficial results of perceiving natural selection not as something that changes a species in accordance with its environment but as something that preserves characteristics beneficial in the s... ...
Natural selection is driven by reproductive success. If a species can reproduce and its offspring survive than any traits in its genotype that assisted in its survival will be passed on from generation to generation and ensure that the species will live on. Around the time the Theory of Evolution was suggested, society was very religious and very pressed on the Theory of Creation, so the publication of Darwin’s The Origin of Species by Means of Natural Selection caused a lot of controversy. Darwin gave the world strong evidence that natural selection and evolution played a major role in the development of the species that we see today. Of course natural selection is not the only process driving evolution.
According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
Natural selection is based on the concept “survival of the fittest” where the most favourable individual best suited in the environment survive and pass on their genes for the next generation. Those individual who are less suited to the environment will die.