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What is Free Evolution? Free evolution is the concept that the natural processes that organisms go through can lead them to evolve over time. This includes the development of new species as well as the transformation of the appearance of existing species. This has been demonstrated by numerous examples of stickleback fish species that can be found in salt or fresh water, and walking stick insect types that prefer specific host plants. These reversible traits cannot explain fundamental changes to the basic body plan. 무료에볼루션 by Natural Selection Scientists have been fascinated by the development of all living creatures that live on our planet for centuries. The most well-known explanation is that of Charles Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well-adapted. Over time, the population of individuals who are well-adapted grows and eventually develops into an entirely new species. Natural selection is a cyclical process that involves the interaction of three factors that are inheritance, variation and reproduction. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity within a species. Inheritance refers to the passing of a person's genetic characteristics to their offspring, which includes both recessive and dominant alleles. Reproduction is the generation of fertile, viable offspring which includes both sexual and asexual methods. Natural selection only occurs when all these elements are in harmony. If, for example an allele of a dominant gene makes an organism reproduce and survive more than the recessive gene, then the dominant allele is more prevalent in a population. However, if the gene confers an unfavorable survival advantage or reduces fertility, it will be eliminated from the population. The process is self reinforcing meaning that an organism that has an adaptive characteristic will live and reproduce more quickly than those with a maladaptive feature. The greater an organism's fitness which is measured by its ability to reproduce and endure, is the higher number of offspring it will produce. Individuals with favorable traits, like the long neck of Giraffes, or the bright white color patterns on male peacocks, are more likely than others to live and reproduce, which will eventually lead to them becoming the majority. Natural selection is only an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics through use or neglect. For example, if a giraffe's neck gets longer through stretching to reach for prey and its offspring will inherit a more long neck. The difference in neck length between generations will continue until the giraffe's neck gets so long that it can no longer breed with other giraffes. Evolution through Genetic Drift In the process of genetic drift, alleles at a gene may reach different frequencies in a population by chance events. Eventually, one of them will attain fixation (become so widespread that it can no longer be removed by natural selection), while the other alleles drop to lower frequencies. This can result in a dominant allele in the extreme. The other alleles are eliminated, and heterozygosity falls to zero. In a small population this could lead to the complete elimination of recessive gene. This is known as a bottleneck effect and it is typical of evolutionary process when a large amount of people migrate to form a new group. A phenotypic bottleneck can also occur when survivors of a disaster such as an epidemic or a massive hunting event, are condensed in a limited area. The survivors will share a dominant allele and thus will have the same phenotype. This could be caused by a war, an earthquake, or even a plague. The genetically distinct population, if left, could be susceptible to genetic drift. Walsh Lewens and Ariew employ a “purely outcome-oriented” definition of drift as any deviation from the expected values for variations in fitness. They cite a famous example of twins that are genetically identical and have the exact same phenotype and yet one is struck by lightening and dies while the other lives and reproduces. This type of drift can play a very important role in the evolution of an organism. It is not the only method for evolution. The primary alternative is a process known as natural selection, where phenotypic variation in the population is maintained through mutation and migration. Stephens argues there is a vast distinction between treating drift as an agent or cause and considering other causes, such as selection mutation and migration as causes and forces. 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 a direction: that is it tends to reduce heterozygosity. He also claims that it also has a magnitude, which is determined by population size. Evolution through Lamarckism Biology students in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is often called “Lamarckism” and it asserts that simple organisms evolve into more complex organisms through the inheritance of traits that are a result of the organism's natural actions, use and disuse. Lamarckism is typically illustrated by a picture of a giraffe stretching its neck further to reach the higher branches in the trees. This would cause giraffes' longer necks to be passed onto their offspring who would grow taller. Lamarck was a French zoologist and, in his inaugural lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th May 1802, he presented an original idea that fundamentally challenged the previous understanding of organic transformation. In his view living things evolved from inanimate matter via the gradual progression of events. Lamarck was not the first to make this claim, but he was widely regarded as the first to offer the subject a comprehensive and general explanation. The most popular story is that Lamarckism was an opponent to Charles Darwin's theory of evolution through natural selection and that the two theories fought it out in the 19th century. Darwinism ultimately won which led to what biologists refer to as the Modern Synthesis. 무료 에볼루션 denies that acquired characteristics can be passed down through generations and instead argues organisms evolve by the selective action of environment factors, including Natural Selection. Lamarck and his contemporaries supported the notion that acquired characters could be passed down to the next generation. However, this notion was never a central part of any of their evolutionary theories. This is due in part to the fact that it was never tested scientifically. It's been more than 200 years since the birth of Lamarck, and in the age genomics, there is a growing evidence base that supports the heritability acquired characteristics. This is referred to as “neo Lamarckism”, or more often epigenetic inheritance. It is a variant of evolution that is just as valid as the more popular Neo-Darwinian model. Evolution through Adaptation One of the most commonly-held misconceptions about evolution is that it is being driven by a struggle for survival. This view is inaccurate and ignores other forces driving evolution. The fight for survival can be more precisely described as a fight to survive in a specific environment, which could be a struggle that involves not only other organisms but also the physical environment. To understand how evolution works it is important to think about what adaptation is. It refers to a specific characteristic that allows an organism to survive and reproduce in its environment. It can be a physiological feature, like feathers or fur or a behavior like moving into shade in hot weather or stepping out at night to avoid cold. The capacity of a living thing to extract energy from its surroundings and interact with other organisms and their physical environments, is crucial to its survival. The organism must have the right genes for producing offspring and to be able to access sufficient food and resources. The organism must be able to reproduce at the rate that is suitable for its specific niche. These elements, along with gene flow and mutations can cause an alteration in the ratio of different alleles in a population’s gene pool. The change in frequency of alleles could lead to the development of new traits, and eventually, new species in the course of time. Many of the characteristics we admire in animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, feathers or fur for insulation and long legs for running away from predators and camouflage to hide. However, a thorough understanding of adaptation requires attention to the distinction between behavioral and physiological traits. Physical characteristics like thick fur and gills are physical traits. Behavior adaptations aren't, such as the tendency of animals to seek companionship or move into the shade in hot temperatures. It is important to keep in mind that the absence of planning doesn't cause an adaptation. A failure to consider the consequences of a decision even if it appears to be logical, can cause it to be unadaptive.