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What is Free Evolution? Free evolution is the concept that the natural processes of organisms can lead to their development over time. This includes the evolution of new species as well as the alteration of the appearance of existing species. Many examples have been given of this, such as different kinds of stickleback fish that can live in fresh or salt water and walking stick insect varieties that prefer particular host plants. These typically reversible traits are not able to explain fundamental changes to the basic body plan. Evolution by Natural Selection Scientists have been fascinated by the development of all the living creatures that live on our planet for centuries. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when those who are better adapted have more success in reproduction and survival than those who are less well-adapted. Over time, the population of well-adapted individuals grows and eventually forms an entirely new species. Natural selection is an ongoing process that involves the interaction of three factors including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity within a species. Inheritance refers to the passing of a person's genetic characteristics to the offspring of that person that includes recessive and dominant alleles. Reproduction is the process of creating fertile, viable offspring. This can be accomplished via sexual or asexual methods. All of these variables must be in harmony to allow natural selection to take place. For instance when a dominant allele at one gene allows an organism to live and reproduce more often than the recessive allele the dominant allele will become more prevalent in the population. If the allele confers a negative survival advantage or reduces the fertility of the population, it will be eliminated. The process is self-reinforcing which means that an organism that has an adaptive characteristic will live and reproduce more quickly than those with a maladaptive trait. The greater an organism's fitness as measured by its capacity to reproduce and survive, is the greater number of offspring it produces. Individuals with favorable traits, such as having a longer neck in giraffes or bright white colors in male peacocks are more likely to survive and produce offspring, and thus will eventually make up the majority of the population over time. Natural selection is an element in the population and not on individuals. This is an important distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or disuse. If a giraffe extends its neck to catch prey and the neck grows longer, then its offspring will inherit this characteristic. The differences in neck size between generations will continue to grow until the giraffe becomes unable to breed with other giraffes. Evolution through Genetic Drift In genetic drift, alleles within a gene can reach different frequencies in a population by chance events. In the end, one will attain fixation (become so common that it can no longer be removed through natural selection), while other alleles will fall to lower frequencies. In the extreme, this leads to one allele dominance. The other alleles are eliminated, and heterozygosity falls to zero. In a small number of people, this could lead to the total elimination of recessive allele. This scenario is called the bottleneck effect. It is typical of an evolutionary process that occurs whenever an enormous number of individuals move to form a group. A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or a mass hunting event are concentrated in an area of a limited size. The survivors are likely to be homozygous for the dominant allele which means that they will all have the same phenotype and will thus share the same fitness characteristics. This can be caused by earthquakes, war, or even plagues. The genetically distinct population, if it remains susceptible to genetic drift. Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected value due to differences in fitness. They give a famous instance of twins who are genetically identical and have identical phenotypes, but one is struck by lightning and dies, while the other lives and reproduces. This type of drift can play a very important part in the evolution of an organism. However, it's not the only method to evolve. Natural selection is the main alternative, in which mutations and migrations maintain phenotypic diversity within a population. Stephens asserts that there is a big difference between treating drift as a force, or an underlying cause, and treating other causes of evolution such as selection, mutation and migration as forces or causes. He claims that a causal mechanism account of drift allows us to distinguish it from the other forces, and this distinction is crucial. He argues further that drift has both a direction, i.e., it tends to eliminate heterozygosity. It also has a size, which is determined based on population size. Evolution by Lamarckism When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution is commonly known as “Lamarckism” and it states that simple organisms grow into more complex organisms via the inheritance of characteristics that are a result of an organism's natural activities usage, use and disuse. Lamarckism is usually illustrated with a picture of a giraffe that extends its neck further to reach leaves higher up in the trees. This process would result in giraffes passing on their longer necks to their offspring, which then get 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 17 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 an escalating series of steps. Lamarck was not the first to suggest that this might be the case, but he is widely seen as giving the subject his first comprehensive and thorough treatment. Get Source is that Charles Darwin's theory on natural selection and Lamarckism were competing during the 19th century. Darwinism eventually won, leading to the development of what biologists now call the Modern Synthesis. This theory denies that acquired characteristics can be inherited and instead suggests that organisms evolve through the selective action of environmental factors, like natural selection. While Lamarck supported the notion of inheritance through acquired characters, and his contemporaries also offered a few words about this idea but it was not a major feature in any of their evolutionary theories. This is partly because it was never scientifically tested. It has been more than 200 year since Lamarck's birth and in the field of genomics, there is a growing body of evidence that supports the heritability-acquired characteristics. This is referred to as “neo Lamarckism”, or more often epigenetic inheritance. It is a form of evolution that is as relevant as the more popular neo-Darwinian model. Evolution through the process of adaptation One of the most common misconceptions about evolution is that it is being driven by a struggle to survive. This is a false assumption and overlooks other forces that drive evolution. The struggle for existence is more accurately described as a struggle to survive in a certain environment. This can include not just other organisms as well as the physical environment. Understanding adaptation is important to comprehend evolution. 에볼루션 블랙잭 refers to a specific feature that allows an organism to live and reproduce within its environment. It can be a physical feature, such as feathers or fur. It could also be a trait of behavior, like moving into the shade during the heat, or coming out to avoid the cold at night. An organism's survival depends on its ability to extract energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism must have the right genes to produce offspring, and it must be able to access sufficient food and other resources. The organism must also be able to reproduce at the rate that is suitable for its specific niche. These factors, in conjunction with gene flow and mutations, can lead to changes in the proportion of different alleles within the population's gene pool. Over time, this change in allele frequencies could result in the emergence of new traits and eventually new species. Many of the features we appreciate in plants and animals are adaptations. For example lung or gills that extract oxygen from the air feathers and fur as insulation, long legs to run away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires a keen eye to the distinction between physiological and behavioral traits. Physiological adaptations, like 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. Furthermore, Get Source is important to understand that a lack of forethought does not make something an adaptation. In fact, failure to consider the consequences of a decision can render it unadaptive even though it may appear to be logical or even necessary.