to understand adpation's role in selection, we have to first understand how adaption is driven. Adaptions is driven by physical conditions and biological conditions. Terrain, weather, and climate are all examples of physical conditions that an animal must adapt to in order to survive. That's not all, animals are also driven to change and evolution by surrounding prey and predators. A prime example of this is the battle between newts, specifically toxic newts, and Garter snakes. Some newts are very toxic, and if eaten could kill hundreds of any of it's predators, except for one. The Garter snake has built up a resistance to toxic newts, and while eating them affects them, it doesn't kill them. In exchange for this resistance, the Garter snakes
A prime example of natural selection is the development of antibiotic resistance in bacteria. In a given population of bacteria, there may be some that carry a short segment of DNA coding for a protein which is resistant to a given antibiotic. If that population now encounters that antibiotic, there is a major selective pressure - those bacteria that do not have the antibiotic resistance gene will die. The only ones that will survive will be the ones carrying that gene. Therefore, those remaining antibiotic resistant specimens will be able to reproduce, passing along the antibiotic ...
In Mivart’s Genesis of Species, the author highlights the inconsistencies of Darwin’s natural selection theory. He supports his assertion by emphasizing how species placed in similar environments acquire different traits, questioning the long-term advantages of these evolved traits, and noting the logical inconsistencies of how traits can span in all directions.
Natural selection is associated with the phrase “survival of the fittest.” This basically means that the fittest individuals can not only survive, but are also able to leave the most offspring. The selection of phenotypes affects the genotypes. For example, if tall pea plants are favored in the environment, then the tall pea plants would leave more offspring behind, meaning that the offspring will carry tall alleles. Phenotypes that are successful have the best adaptations (characteristics that help an individual to survive and reproduce) to their environment. These adaptation arise from the interactions with living and nonliving aspects of the environment. Some nonliving aspects of the environment are climate, water availability, and concentration of mineral sin the
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 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.
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.
This chapter covers the variations of selection. Selection is a process, a description of how genes that produce better adaptations become more frequent over time. Species don’t try to adapt to their environment. Adaptation to the environment is inevitable if a species has the right kind of genetic variation. (pg. 117) The thought that “everything happens by chance” is essentially wrong. Evolution by selection is a combination of randomness and lawfulness. First a “random” process is the occurrence of mutations that generate an array of genetic variants, both good and bad; and then a “lawful” process (natural selection) that creates these variations. (pg.118) DNA is random, and this shows in humans and animals. For example, a humans parents
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.
“Animals are adapted to their conditions in subtle and marvelous ways (Boyd, R., & Silk, J. 1997:2).” It is commonly recognized that Darwin identified adaptations through Natural Selection: traits that are advantageous to survival will be retained in the population through reproduction. Natural Selection further indicates that traits will survive when they are most beneficial to an individual’s fitness. While Natural Selection and Mutation effectively explains adaptive fitness qualities and variance among populations, it fails to explain species beautiful ornamental traits that are not necessarily beneficial to fitness. The extravagant tails of a male peacocks, the neck of a giraffe, and bright colored plumage of birds are attributes designed to maximize reproductive success. Muscularity, sexual dimorphism (general size difference between sexes), male beards, penis size, calculated fat storage (in the breasts and hips for women), and co-parenting are adaptations in humans explained through sexual selection: specifically, through competition. Natural and Sexual Selection are competing and paralleling factors that define human evolution. While Natural Selection may define the necessity to impart certain genes, Sexual Selection quickly allows adaptations to occur through competition. Evolution
With the studies that Charles Darwin obtained he published his first work, “The Origin of Species.” In this book he explained how for millions of years animals, and plants have evolved to better help their existence. Darwin reasoned that these living things had gradually changed over time to help themselves. The changes that he found seemed to have been during the process of reproduction. The traits which would help them survive became a dominant trait, while the weaker traits became recessive. A good example of what Darwin was trying to explain is shown in giraffes. Long-necked giraffes could reach the food on the trees, while the short-necked giraffes couldn’t. Since long necks helped the giraffes eat, short-necked giraffes died off from hunger. Because of this long-necks became a dominant trait in giraffes. This is what Charles Darwin would later call natural selection.
Natural selection was one of the most important discoveries in the Nineteenth century, and it has changed peoples’ position ever since. Natural selection also provides people a new chance to find truth in the world. Even though it has been demonstrated for over one hundred years, we can still try to find new information from it. Today, natural selection is a very important subject that a lot of scientists try to use to explain different kinds of evolutionary questions.
It also allows species to survive. It produces new and different species through ancestral populations of organisms and moves them to new populations. Both natural selection and genetic drift decrease genetic variation. If they were the only mechanisms of evolution, populations would eventually become homogeneous and further evolution would be impossible. There are, however, mechanisms that replace variation depleted by selection and drift (Colby).
Many scientists in the past, such as Aristotle and Plato, believed that there were no changes in populations; however, other scientists, such as Darwin and Wallace, arose and argued that species inherit heritable traits from common ancestors and environmental forces drives out certain heritable traits that makes the species better suited to survive or be more “fit” for that environment. Therefore, species do change over a period of time and they were able to support their theory by showing that evolution does occur. There were four basic mechanisms of evolution in their theory: mutation, migration, genetic drift, and natural selection. Natural selection is the gradual process by which heritable traits that makes it more likely for an organism to survive and successfully reproduce increases, whereas there is a decline in those who do have those beneficial heritable traits (Natural Selection). For example, there is a decrease in rain which causes a drought in the finches’ environment. The seeds in the finches’ environment would not be soft enough for the smaller and weaker beak finches to break; therefore, they cannot compete with the larger and stronger beak finches for food. The larger and stronger beak finches has a heritable trait that helps them survive and reproduce better than others for that particular environment which makes them categorized under natural selection (Freeman, 2002).
The theory of natural selection is not limited to inheritable and beneficial variations of a species. It also relies a great deal on the population growth and death of a species. For a species to continue to exist it must make sure of a few things. It must first produce more offspring that survive. If this is not done then the species is obviously going to die off. It is also important for the species to propagate at such a rate as to allow for variance, for it is variance that will ultimately allow the animal to exist comfortably in his surroundings. In his studies, Darwin was led to understand that “…the species of the larger genera in each country would oftener present varieties, than the species of the smaller genera;” (p. 55). Thus the larger species would adapt while the smaller one would not. And to quote Darwin again, “…if any one species does not become modified and improved in a corresponding degree with its competitors, it will soon be exterminated.” (p. 102)
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.