Models Of Speciation By Sexual Selection On Polygen By Russell Lande

There is a better chance of the traits being passed on when sexual selection is at

The PBS Documentary, Why Sex?, starts out in the beginning with special guests, peacocks. The male peacocks’ tail features are not only for its unique beauty, but, they also attract other predators and female peahens only mate with well endowed males. Which in this case means if the male peacocks don’t have a “fancy” enough tail according to the female peahens, unfortunately means no sex permitted for them. Every living thing on this Earth is programed to pass their genes to the next generation. Even if that means you have to risk fighting or even dying for. For evolution to continue, sex is of greater importance than even life itself.

In what he called the ‘survival of the fittest’, Darwin suggested that through the process of natural selection animals with particular characteristics, as a result of possessing advantageous alleles, will survive. However, those with maladaptive genes cannot adapt to changes in environmental conditions, so will die or become extinct. Dowling (1994) stated that this process depends on three principles: species diversity, interaction and the spread of a species as a result of differential amplification. Sexual selection is another component of Darwin’s research, which explains the best strategies adopted for passing on genes to offspring. Moreover, there are problems with Darwin’s theory such as his attempts to generalise animal behaviour to the way in which humans interact in their environment. However, he has presented compelling evidence which is very scientific in its approach and methodology. Furthermore, contrary to Darwin’s evolutionary idea of survival of an individual, Dawkins (1976) suggested that the survival of the genes is more important.

Darwin suggested that females preferred certain phenotypic traits as females could gain direct benefit from these, for example, certain male characters are able to provide resources or offspring and increase fecundity (Mota, 2010) .

In the case of ring species, natural selection and sexual selection each play a role in the divergence of ring species. Selective pressures allowed one phenotype to survive better than others in a certain area; sexual selection could cause divergence because organisms choose mates based on phenotypes. In the case of salamanders, natural selection affected divergence because organisms with certain coloration survived better in coastal or inland environments. In warblers, sexual selection and natural selection seem to play a part in the divergence of the ring species, as forest density and migration distance is variable and affects survival of the species. Molecular and morphological evidence can be used to support multiple species by showing

Although sexual selection may seem like natural selection, they both happen to have different features that separate them from one another. Sexual selection involves dominance and competition between organisms. Furthermore, it deals with the attractiveness some traits hold when drawing attention to other mates. A common example is that of the peacock and its vibrant feathers. The peahens are attracted to flashy feathers that the peacock flaunts, and they will eventually choose the mate that displays itself as the most extravagant. Ultimately, they will procreate and the peacock will pass on the trait involving his feathers since he was chosen as a mate.

Albeit, the sexual selection theory is presumed force of natural selection causing individuals to develop reproductive strategies which maximize the like hood of their producing the fittest possible offspring. Otherwise, suggested a competition between males and competition for females as the two most likely mechanism of sexual selection theory.

Social scientist find it attractive to accept biological explanation concerning differences because, first biological explanations have the ring of “true” science to them: Because their theories are based on “objective scientific facts,” the arguments of natural scientists are extraordinary persuasive (Kimmel 20). The second biological explanations seem to accord with our own observations: Women and men seem too different to us most of the time (Kimmel 20). For example, women are more emotional therefore they seem to love chick flicks because of the meanings and actions of love, meanwhile men are more aggressive so they prefer to watch action movies. Lastly the third biological explanation would be that there’s also a certain conceptual tininess to biological explanations, because the social arrangements between women and men seem to stem directly and inevitably from the differences between us (Kimmel 20).

Most diploid species maintain a one to one sex ratio because it is evolutionarily stable (Fisher, 1930). However, when population ratios do not fit the Fisherian sex ratio of one to one, selection will favor the gene/allele that is in limited supply until their frequency is greater or equal to the competing gene (Fisher, 1930). Therefore, selection works at the level of the gene in maintaining evolutionarily stable Fisherian sex ratios.

The first few chapters discuss in depth both the general rules for mate selection and the differences in mate selection and varying preferences for male and female genders. As explained in the intro the author theorizes that the current behavior of humans in relation to mating behavior can be linked to our evolutionary past. He references Charles Darwin 's theory of evolution and his idea of natural selection, which is the the process through which organisms adapt to their environment and in doing so tend to

Natural selection is considered one of the most important processes for a variety of species and the environment which allows the fittest organisms to produce offspring. To prevent a species from extinction, it is necessary for them to adapt to the surrounding environment. The species which have the ability to adapt to new surroundings will be able to pass their genes through reproduction. Within the process of natural selection, it is possible for the original genetic make-up of a species to become altered. The team will report on the different processes of basic mechanisms of evolution, how natural selection results in biodiversity and why biodiversity is important to continued evolution. The sources of genetic

Sexual selection was an idea proposed by Darwin and refers to the process in which males and females attempt to maximize their chances of reproductive success. Within a species there are certain characteristics that make individuals attractive to potential mates. An example of this is in peacocks, female peacocks are attracted to males with long brightly colored tails, even though this makes them easier to be spotted by predators. This characteristic then evolves within the species due to how males with this characteristic have a higher chance of reproductive success and their characteristics being passed on to surviving offspring.

Sexual selection can best be described by the definition given by Darwin himself. Sexual selection is “the advantage which certain individuals have over other individuals of the same species solely in respect of reproduction” (Hosken et al, 2011). Sexual selection occurs throughout the animal kingdom, where male frogs dominate through the depth of their croak, and certain peacocks reign superior based on the colour and intricate detail on their tails. They remain superior to their lesser counterparts as they bear more admirable characteristics, from which they are chosen by females of the same species.

If these traits that it possesses that made it different were useful than that creature may reproduce more than normal. Of course in Darwin’s day DNA had not been discovered but it was known that traits were passed to offspring. Natural selection is when the organisms with good traits survive the trials of nature. Artificial selection is what breeders do, the cow that gives more milk, or the plant that produces larger fruit are selected to be reproduced. Encyclopedia Encarta defines natural selection as “the process by which environmental effects lead to varying degrees of reproductive success among individuals of a population of organisms with different hereditary characters, or traits. The characters that inhibit reproductive success decrease in frequency from generation to generation. The resulting increase in the proportion of reproductively successful individuals usually enhances the adaptation of the population to its environment”

“If no such variations exist, the population rapidly goes extinct because it cannot adapt to a changing environment” (O’Neil, 1998-2013). Scientists call this reproductive success. “Within a specific environment context, one genotype will be better than another genotype in survival or reproduction for certain reasons having to do with the way its particular features relate to the environment or relate to other organisms within the population” (Futuyma, 2000-2014). The theory of evolution is explicable through various kinds of scientific research.