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What is Free Evolution? Free evolution is the notion that natural processes can cause organisms to evolve over time. This includes the emergence and development of new species. Numerous examples have been offered of this, including various varieties of stickleback fish that can be found in salt or fresh water, as well as walking stick insect varieties that favor particular host plants. These reversible traits however, are not able to explain fundamental changes in basic body plans. Evolution through Natural Selection The development of the myriad living organisms on Earth is a mystery that has fascinated scientists for centuries. The most well-known explanation is Charles Darwin's natural selection process, an evolutionary process that occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well adapted. As time passes, the number of well-adapted individuals becomes larger and eventually develops into an entirely new species. Natural selection is an ongoing process that involves the interaction of three factors: variation, inheritance and reproduction. Mutation and sexual reproduction increase genetic diversity in a species. Inheritance refers the transmission of genetic traits, which include both dominant and recessive genes, to their offspring. Reproduction is the process of producing viable, fertile offspring. 무료 에볼루션 can be done via sexual or asexual methods. All of these elements have to be in equilibrium for natural selection to occur. If, for example, a dominant gene allele makes an organism reproduce and live longer than the recessive gene allele then the dominant allele is more prevalent in a population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will go away. This process is self-reinforcing which means that an organism with an adaptive trait will live and reproduce far more effectively than those with a maladaptive trait. The more fit an organism is, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with good traits, such as having a longer neck in giraffes and bright white color patterns in male peacocks, are more likely to survive and produce offspring, and thus will become the majority of the population over time. Natural selection only affects populations, not on individual organisms. This is a major distinction from the Lamarckian theory of evolution which argues that animals acquire traits by use or inactivity. If a giraffe extends its neck to catch prey, and the neck becomes longer, then the offspring will inherit this trait. The differences in neck size between generations will continue to grow until the giraffe is no longer able to breed with other giraffes. Evolution through Genetic Drift Genetic drift occurs when alleles of a gene are randomly distributed in a group. In the end, one will attain fixation (become so widespread that it is unable to be removed by natural selection), while the other alleles drop to lower frequency. This could lead to dominance at the extreme. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small group it could result in the complete elimination the recessive gene. This is known as the bottleneck effect. It is typical of an evolutionary process that occurs whenever an enormous number of individuals move to form a population. 무료에볼루션 could happen when the survivors of a catastrophe like an epidemic or a mass hunting event, are condensed into a small area. The survivors will share an dominant allele, and will share the same phenotype. This could be caused by war, earthquakes, or even plagues. Whatever the reason the genetically distinct population that remains could be susceptible to genetic drift. Walsh Lewens, Walsh, and Ariew define drift as a deviation from the expected value due to differences in fitness. They cite a famous instance of twins who are genetically identical and have the exact same phenotype but one is struck by lightning and dies, while the other lives and reproduces. This kind of drift could be crucial in the evolution of the species. This isn't the only method for evolution. The primary alternative is to use a process known as natural selection, where the phenotypic variation of an individual is maintained through mutation and migration. Stephens argues that there is a big distinction between treating drift as a force or a cause and treating other causes of evolution like selection, mutation and migration as forces or causes. Stephens claims that a causal process account of drift allows us differentiate it from other forces, and this distinction is crucial. He also argues that drift has both an orientation, i.e., it tends to eliminate heterozygosity. It also has a size that is determined by the size of the population. Evolution through Lamarckism In high school, students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution is often referred to as “Lamarckism” and it states that simple organisms grow into more complex organisms via the inheritance of traits that result from an organism's natural activities, use and disuse. Lamarckism is typically illustrated with a picture of a giraffe that extends its neck longer to reach leaves higher up in the trees. This would cause giraffes to pass on their longer necks to 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 the conventional wisdom on organic transformation. According to Lamarck, living things evolved from inanimate matter through a series gradual steps. Lamarck was not the first to suggest that this might be the case but his reputation is widely regarded as being the one who gave the subject its first broad and comprehensive analysis. The popular narrative is that Lamarckism became an opponent to Charles Darwin's theory of evolution through natural selection and that the two theories battled it out in the 19th century. Darwinism eventually won and led to the creation of what biologists today refer to as the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be acquired through inheritance and instead suggests that organisms evolve by the symbiosis of environmental factors, including natural selection. Lamarck and his contemporaries endorsed the notion that acquired characters could be passed down to the next generation. However, this concept was never a major part of any of their theories about evolution. This is largely due to the fact that it was never validated scientifically. However, it has been more than 200 years since Lamarck was born and in the age of genomics there is a vast amount of evidence to support the heritability of acquired traits. It is sometimes referred to as “neo-Lamarckism” or, more frequently epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model. Evolution through Adaptation One of the most popular misconceptions about evolution is that it is driven by a sort of struggle to survive. This notion is not true and ignores other forces driving evolution. The fight for survival can be more effectively described as a struggle to survive within a specific environment, which can include not just other organisms, but also the physical environment. To understand how evolution operates, it is helpful to consider what adaptation is. The term “adaptation” refers to any specific feature that allows an organism to survive and reproduce in its environment. It could be a physiological structure such as fur or feathers or a behavioral characteristic such as a tendency to move into the shade in hot weather or coming out at night to avoid the cold. The survival of an organism is dependent on its ability to extract energy from the surrounding environment and interact with other organisms and their physical environments. The organism should possess the right genes for producing offspring, and be able to find enough food and resources. The organism should also be able to reproduce at a rate that is optimal for its particular niche. These factors, together with mutation and gene flow, lead to an alteration in the percentage of alleles (different types of a gene) in the population's gene pool. This shift in the frequency of alleles can lead to the emergence of novel traits and eventually, new species as time passes. A lot of the traits we admire about animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, feathers or fur to protect themselves long legs to run away from predators, and camouflage to hide. However, a complete understanding of adaptation requires a keen eye to the distinction between behavioral and physiological characteristics. Physical characteristics like large gills and thick fur are physical traits. The behavioral adaptations aren't an exception, for instance, the tendency of animals to seek companionship or retreat into shade in hot weather. In addition, it is important to understand that lack of planning does not mean that something is an adaptation. Inability to think about the effects of a behavior even if it appears to be rational, could cause it to be unadaptive.