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What is Free Evolution? Free evolution is the concept that natural processes can cause organisms to evolve over time. This includes the appearance and development of new species. A variety of examples have been provided of this, including various kinds of stickleback fish that can live in either salt or fresh water, and walking stick insect varieties that prefer particular host plants. These typically reversible traits cannot explain fundamental changes to basic body plans. Evolution through Natural Selection Scientists have been fascinated by the evolution of all the living creatures that inhabit our planet for centuries. Charles Darwin's natural selectivity is the most well-known explanation. This is because individuals who are better-adapted have more success in reproduction and survival than those who are less well-adapted. As time passes, the number of well-adapted individuals becomes larger and eventually creates an entirely new species. Natural selection is an ongoing process and involves the interaction of three factors that are: reproduction, variation and inheritance. Mutation and sexual reproduction increase genetic diversity in an animal species. Inheritance refers the transmission of a person's genetic traits, including recessive and dominant genes to their offspring. Reproduction is the process of producing fertile, viable offspring which includes both sexual and asexual methods. All of these factors must be in balance for natural selection to occur. For example the case where the dominant allele of a gene allows an organism to live and reproduce more frequently than the recessive allele the dominant allele will become more prevalent within the population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will go away. This process is self-reinforcing meaning that the organism with an adaptive trait will live and reproduce more quickly than one with a maladaptive characteristic. The more offspring an organism can produce the more fit it is which is measured by its ability to reproduce itself and live. People with good characteristics, like longer necks in giraffes and bright white colors in male peacocks are more likely to be able to survive and create offspring, which means they will eventually make up the majority of the population over time. Natural selection only acts on populations, not on individual organisms. This is a major distinction from the Lamarckian evolution theory that states that animals acquire traits either through use or lack of use. If a giraffe expands its neck to catch prey, and the neck becomes longer, then the offspring will inherit this characteristic. The difference in neck length between generations will continue until the giraffe's neck becomes so long that it can no longer breed with other giraffes. Evolution through Genetic Drift Genetic drift occurs when alleles of a gene are randomly distributed within a population. Eventually, one of them will reach fixation (become so common that it can no longer be removed by natural selection), while other alleles will fall to lower frequencies. This can lead to a dominant allele at the extreme. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small group, this could lead to the total elimination of recessive allele. This scenario is called the bottleneck effect and is typical of the evolutionary process that occurs whenever a large number individuals migrate to form a population. A phenotypic bottleneck may also occur when the survivors of a disaster like an outbreak or mass hunt event are confined to an area of a limited size. The surviving individuals will be largely homozygous for the dominant allele which means that they will all share the same phenotype and consequently have the same fitness traits. This can be caused by war, earthquakes, or even plagues. The genetically distinct population, if left, could be susceptible to genetic drift. Walsh Lewens, Walsh, and Ariew define drift as a deviation from expected values due to differences in fitness. They give the famous example of twins who are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, but the other continues to reproduce. This type of drift can play a very important role in the evolution of an organism. It's not the only method for evolution. The main alternative is to use a process known as natural selection, in which the phenotypic variation of a population is maintained by mutation and migration. Stephens claims that there is a big difference between treating the phenomenon of drift as a force, or an underlying cause, and treating other causes of evolution like mutation, selection, and migration as forces or causes. He claims that a causal-process account of drift allows us differentiate it from other forces, and this distinction is essential. He also claims that drift has a direction, that is, it tends to eliminate heterozygosity. It also has a specific magnitude that is determined by the size of the population. Evolution through Lamarckism Biology students in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is often known as “Lamarckism” and it states that simple organisms develop into more complex organisms via the inheritance of characteristics that are a result of the natural activities of an organism, use and disuse. Lamarckism is illustrated through the giraffe's neck being extended to reach higher branches in the trees. This causes the necks of giraffes that are longer to be passed on to their offspring who would then become taller. Lamarck Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to Lamarck, living creatures evolved from inanimate materials through a series gradual steps. Lamarck was not the first to propose this, but he was widely regarded as the first to offer the subject a thorough and general treatment. The predominant story is that Charles Darwin's theory of natural selection and Lamarckism were rivals in the 19th Century. Darwinism ultimately prevailed which led to what biologists refer to as the Modern Synthesis. This theory denies the possibility that acquired traits can be inherited and instead suggests that organisms evolve through the selective action of environmental factors, like natural selection. Although Lamarck believed in the concept of inheritance by acquired characters and his contemporaries also spoke of this idea however, it was not a major feature in any of their evolutionary theorizing. This is due in part to the fact that it was never validated scientifically. It's been over 200 years since the birth of Lamarck, and in the age genomics, there is an increasing body of evidence that supports the heritability of acquired traits. This is often called “neo-Lamarckism” or, more often epigenetic inheritance. This is a version that is just as valid as the popular Neodarwinian model. Evolution by adaptation One of the most common misconceptions about evolution is that it is driven by a type of struggle to survive. In reality, this notion is inaccurate and overlooks the other forces that are driving evolution. The fight for survival can be better described as a fight to survive in a specific environment. This may include not just other organisms but also the physical environment. Understanding adaptation is important to comprehend evolution. The term “adaptation” refers to any specific characteristic that allows an organism to survive and reproduce in its environment. It can be a physiological structure such as feathers or fur, or a behavioral trait, such as moving into the shade in the heat or leaving at night to avoid cold. The survival of an organism is dependent on its ability to extract energy from the environment and interact with other organisms and their physical environments. The organism must have the right genes to produce offspring, and must be able to access enough food and other resources. Moreover, the organism must be able to reproduce itself in a way that is optimally within its environment. These factors, together with mutations and gene flow can cause an alteration in the ratio of different alleles in the population's gene pool. As time passes, this shift in allele frequencies could result in the emergence of new traits and ultimately new species. Many of the features that we admire about animals and plants are adaptations, for example, the lungs or gills that extract oxygen from the air, feathers or fur for insulation, long legs for running away from predators and camouflage to hide. However, a thorough understanding of adaptation requires paying attention to the distinction between physiological and behavioral traits. 에볼루션 바카라 무료 like the thick fur and gills are physical characteristics. The behavioral adaptations aren't like the tendency of animals to seek out companionship or to retreat into the shade during hot temperatures. It is also important to remember that a insufficient planning does not result in an adaptation. In fact, failing to think about the consequences of a behavior can make it unadaptive even though it appears to be logical or even necessary.