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What is Free Evolution? Free evolution is the idea that natural processes can cause organisms to develop over time. This includes the appearance and growth of new species. Numerous examples have been offered of this, including various varieties of fish called sticklebacks that can be found in fresh or salt water and walking stick insect varieties that favor specific host plants. These are mostly reversible traits, however, cannot explain fundamental changes in body plans. Evolution by Natural Selection Scientists have been fascinated by the evolution of all the living organisms that inhabit our planet for ages. Charles Darwin's natural selection theory is the best-established explanation. This is because people who are more well-adapted have more success in reproduction and survival than those who are less well-adapted. As time passes, the number of individuals who are well-adapted grows and eventually forms a new species. Natural selection is an ongoing process that is characterized by the interaction of three factors that are inheritance, variation and reproduction. Sexual reproduction and mutations increase genetic diversity in a species. Inheritance is the transfer of a person's genetic traits to their offspring, which includes both recessive and dominant alleles. Reproduction is the production of fertile, viable offspring, which includes both sexual and asexual methods. Natural selection only occurs when all of these factors are in balance. For instance the case where a dominant allele at a gene allows an organism to live and reproduce more often than the recessive one, the dominant allele will become more prevalent in the population. However, if the allele confers a disadvantage in survival or reduces fertility, it will disappear from the population. This process is self-reinforcing meaning that a species with a beneficial characteristic is more likely to survive and reproduce than one with an unadaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the more offspring it produces. Individuals with favorable characteristics, like a longer neck in giraffes or bright white colors in male peacocks, are more likely to survive and produce offspring, which means they will become the majority of the population over time. Natural selection only affects populations, not on individual organisms. This is an important distinction from the Lamarckian theory of evolution, which states that animals acquire characteristics through use or neglect. For instance, if the giraffe's neck gets longer through stretching to reach prey, its offspring will inherit a longer neck. The length difference between generations will continue until the neck of the giraffe becomes too long that it can not breed with other giraffes. Evolution by Genetic Drift Genetic drift occurs when the alleles of a gene are randomly distributed within a population. In the end, only one will be fixed (become common enough to no longer be eliminated by natural selection) and the rest of the alleles will decrease in frequency. In extreme cases this, it leads to a single allele dominance. The other alleles are essentially eliminated and heterozygosity has diminished to zero. In a small number of people this could lead to the complete elimination the recessive gene. This scenario is called the bottleneck effect and is typical of the evolution process that occurs when the number of individuals migrate to form a group. A phenotypic bottleneck can also occur when survivors of a disaster like an outbreak or mass hunt event are confined to the same area. The survivors will share an dominant allele, and will share the same phenotype. This may be the result of a war, an earthquake or even a cholera outbreak. The genetically distinct population, if it remains, could be susceptible to genetic drift. Walsh, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a “purely outcome-oriented” definition of drift as any departure from the expected values of different fitness levels. They cite a famous instance of twins who are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces. This kind of drift could play a significant part in the evolution of an organism. It is not the only method for evolution. Natural selection is the most common alternative, where mutations and migration keep phenotypic diversity within the population. Stephens argues that there is a major difference between treating drift as a force, or a cause and treating other causes of evolution, such as selection, mutation and migration as forces or causes. He claims that a causal-process explanation of drift lets us differentiate it from other forces, and this differentiation is crucial. He further argues that drift has an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined based on population size. Evolution by Lamarckism When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, also referred to as “Lamarckism is based on the idea that simple organisms transform into more complex organisms adopting traits that are a product of the organism's use and misuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher levels of leaves in the trees. This causes giraffes' longer necks to be passed to their offspring, who would then become taller. Lamarck, a French zoologist, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. According to Lamarck, living things evolved from inanimate material through a series gradual steps. Lamarck was not the first to suggest that this could be the case, but the general consensus is that he was the one giving the subject its first general and thorough treatment. The most popular story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection, and that the two theories battled out in the 19th century. 무료에볼루션 prevailed which led to what biologists refer to as the Modern Synthesis. The theory denies that acquired characteristics are passed down from generation to generation and instead argues that organisms evolve through the selective influence of environmental factors, including Natural Selection. Although Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries paid lip-service to this notion however, it was not a central element in any of their theories about evolution. This is partly because it was never tested scientifically. However, it has been more than 200 years since Lamarck was born and, in the age of genomics, there is a large body of evidence supporting the heritability of acquired traits. This is also referred to as “neo Lamarckism”, or more generally epigenetic inheritance. This is a variant that is as reliable as the popular neodarwinian model. Evolution through the process of adaptation One of the most common misconceptions about evolution is that it is driven by a sort of struggle for survival. This view is inaccurate and ignores other forces driving evolution. The struggle for survival is more precisely described as a fight to survive within a particular environment, which may involve not only other organisms but as well the physical environment. To understand how evolution operates it is important to understand what is adaptation. It refers to a specific feature that allows an organism to survive and reproduce in its environment. It could be a physiological structure such as feathers or fur, or a behavioral trait such as a tendency to move into the shade in hot weather or stepping out at night to avoid the cold. The capacity of an organism to draw energy from its environment and interact with other organisms as well as their physical environment, is crucial to its survival. The organism must have the right genes to create offspring and be able find sufficient food and resources. Moreover, the organism must be capable of reproducing at a high rate within its environment. These factors, together with gene flow and mutation, lead to a change in the proportion of alleles (different types of a gene) in a population's gene pool. This change in allele frequency can result in the emergence of new traits and eventually new species in the course of time. Many of the characteristics we find appealing in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from the air feathers and fur for insulation long legs to run away from predators and camouflage to conceal. To understand adaptation it is crucial to discern between physiological and behavioral traits. Physiological adaptations like the thick fur or gills are physical characteristics, whereas behavioral adaptations, like the tendency to search for friends or to move to shade in hot weather, are not. It is important to remember that a the absence of planning doesn't cause an adaptation. A failure to consider the implications of a choice, even if it appears to be rational, may cause it to be unadaptive.