Sexual selection
Sexual selection is a biological mechanism that influences how physical traits develop within a species, particularly in relation to attracting mates. It involves two primary components: mate choice, where one sex selects a partner based on desirable characteristics, and competition, where individuals of the same sex vie for access to mates. This process is a subset of natural selection and plays a significant role in the evolution of species by enhancing reproductive success. For example, male frogs may attract females through specific mating calls, while male animals often display physical prowess or ornaments, such as bright colors or antlers, to impress females and deter rivals.
Historically, Charles Darwin proposed that sexual selection contributes to species adaptation and survival, suggesting its impact on both animal behavior and human relationships. In modern contexts, sexual selection generates significant discussion across various fields, including evolutionary psychology and sociobiology. Factors influencing mate preferences can range from physical traits to displays of intelligence and creativity. Additionally, society's evolving standards of beauty and desirability reflect ongoing sexual selection processes. Current research continues to explore how these dynamics influence population health and species survival, indicating that sexual selection remains a relevant and complex topic in the study of biodiversity and human behavior.
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Sexual selection
Sexual selection is how physical traits develop in a species, enhancing chances for success in attracting mates; it is also the choice of a mate based on certain characteristics of a member of the opposite sex of that species. Sexual selection is a mechanism of natural selection, which claims a species survives, adapts, and evolves physiologically, behaviorally, biochemically, and developmentally, reflecting influences of genetics and environment. Sexual selection involves two actions, the outcomes of which are to guarantee reproduction: one member of one biological sex selects a mating partner of the other sex of the same species. The second refers to the competition between members of the same sex getting access to a member of the opposite sex and ensuring a willingness to mate. Croaking is the mating call of frogs. Females choose male partners based on the tone and tenor of male croaking and what they value in the male’s territory. Males in some species become aggressive or thrilling in sexual selection by showing off their physical prowess to impress the females and scare away other males.
Background
Nineteenth-century naturalist and geologist Charles Darwin studied the origins of life forms and their changes. He concluded that species descend from common ancestors in the process of natural selection by sexual selection. Species reproduce in order to maintain their existence. Biologists sometimes refer to this as artificial selection in selective breeding. Natural scientists believe sexual selection is the mechanism leaving the strong to survive and the weak to fall to extinction if they do not adapt. Species developed physical traits to attract mates, like coloration in birds, increased size for strength and dominance among certain animals, or adornments like antlers.
Sexual selection actions occur before copulation and after sexual intercourse. Depending on the species, these include male-to-male combat. Females also have a choice of action. In certain mammals and birds, females are known to purge sperm from males with whom they do not want to procreate. Darwin further theorized THAT sexual selection in humans is affected by appearances. Men have beards and are hairy after millions of years of sexual selection. In the twenty-first century, there are theories suggesting human behavior, including humor, musical abilities, art and verbal creativity, and other attractive characteristics, plays an important role in ensuring survival. Human sexual selection might be the reason males have traditionally had sex with more than one female: multiple wives to produce many offspring. Wealth and power are significant traits in human sexual selection. King Solomon had one thousand wives and thousands of offspring.
Females have also been choosy, selecting males with whom they are willing to mate when in their power to do so. Females of most species sexually select males who are healthy, physically attractive, providing access to food and safe quarters; females want to feel safe, protected from other harassing males, parasites, and diseases. Following the act of sexual intercourse, females in some species can eject sperm. Females mate with different males, choosing which male’s sperm they want to fertilize their eggs.
Sexual Selection Today
One English geneticist and statistician concludes that the purpose of sexual selection is to increase the value-preferred traits, thus increasing positive feedback between male and female.
Sexual selection in humans is a flash point for controversy, sparking great debate in theology, politics, and science. Controversy about sexual selection kept biologists from including it in natural selection for nearly four decades in the mid-1900s. The debate centers on three fields of studies: evolutionary psychology, human behavioral ecology, and sociobiology.
New insights from science offer heuristic value in understanding sexual selection. Antlers and horns not only deter predators, but also help determine the winner among males in tournaments for dominance; this has been found in studies to lead to first-choice access to females for copulation. Eye contact among butterflies and fish is used to ward off predators. A ten-year-long study of flour beetles reported in 2015 that sexual selection of mates ensures the health of the population and prevents extinction. The recent studies and reports from anthropologist David Puts suggests that sexual selection among humans in advanced nations make beauty, fashion, and physical fitness important criteria in mating.
According to studies, women prefer intelligence, creativity, and humor for long-term relationships, but not necessarily near their time of ovulation. Then they prefer characteristics of good genes that indicate the males are free from diseases, have larger penises for pleasure and sperm retention, have vigor and a masculine look, appear dominant, and capable of physically protecting females against predators. The importance of contests between males in sexual selection is recorded in ancient literature, history (the battle between Caesar and Mark Antony for the love of Cleopatra sparked a war), theatrical operas, Shakespeare, and modern-day soap operas.
Sexual selection has become an industry in the digital age. Mate choice theories are the fodder for "dating sites." Concomitantly, the exercise business, the penchant for extreme sports, the popularity of contact sports, the predilection to build muscle and cut the fat, and healthy eating all demonstrate the competitive lengths to which males will go to attract a mate. There are less savory actions in male competitiveness for sexual selection—bullying, macho gangster dress and lifestyle, and violence. Female beauty enhancements like makeup, hairstyling, physical fitness, and plastic surgery can be considered modern-day actions to attract a mate. Plumage elaboration in birds and ornamentation and adornments in animals correlate with human sexual selection.
With new technologies, modern science finds there are selfish genetic elements present in the cell of an organism. These undermine normal patterns of inheritance, increasing these genes in subsequent generations. This opened a new field of study exploring the influence of selfish genetic elements on male and female reproduction and shaping mating systems. There are studies underway on the impact on sexual selection of mate choice; what mate preferences are learned traits, and how and when such learning takes place. New technologies and the plethora of research money are fueling fascinating research and study about sexual selection, reproduction, and the future of species.
Bibliography
Betzig, Laura. "Politics as Sex: The Old Testament Case." Evolutionary Psychology. 3 (2005): 326-46. Web. 19 June 2016.
Brennan, Patricia L. R. "Sexual Selection." The Nature Education Knowledge Project. Nature Education, 2014. Web. 19 June 2016.
Dale, James, et al. "The Effects of Life History and Sexual Selection on Male and Female Plumage Colouration." Nature. Springer Nature. Macmillan Publishers 527 (November 2015): 367-70. Print.
Janicke, Tim. "Sexual Selection: Competition for Resources Provided by Mating Partners." Behavioral Ecology, 13 Mar. 2024, doi.org/10.1093/beheco/arae016. Accessed 25 Nov. 2024.
Mosing, Miriam A., et al. "Did Sexual Selection Shape Human Music? Testing Predictions From the Sexual Selection Hypothesis of Music Evolution Using a Large Genetically Informative Sample of Over 10,000 Twins." Evolution and Human Behavior36.5 (September 2015): 359-66. Web. 19 June 2016.
Puts, David A. "Beauty and the Beast: Mechanisms of Sexual Selection in Humans." Evolution and Human Behavior 31. (2010): 157-75. Web. 19 June 2016.
Van Whyhe, John, ed. "The Complete Works of Charles Darwin Online." Darwin Online. Arts and Humanities Research Council, 2002. Web. 19 June 2016.
Verzijden, Machteld N., et al. "The Impact of Learning on Sexual Selection and Speciation." Trends in Ecology & Evolution 27. 9 (September 2012):.511-19. Web. 19 June 2016.
Wedell, Nina, and Tom Price. "Selfish Genetic Elements and Sexual Selection." Current Perspectives on Sexual Selection 9 (29 2015): 165-90. Web. 19 June 2016.