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What is Free Evolution? Free evolution is the notion that the natural processes of organisms can cause them to develop over time. This includes the appearance and development of new species. Numerous examples have been offered of this, including various kinds of stickleback fish that can live in either fresh or salt water and walking stick insect varieties that favor particular host plants. These mostly reversible trait permutations can't, however, explain fundamental changes in body plans. Evolution through Natural Selection The development of the myriad of living creatures on Earth is a mystery that has fascinated scientists for many centuries. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when 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 forms a new species. Natural selection is a cyclical process that involves the interaction of three factors including inheritance, variation, and reproduction. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity within an animal species. Inheritance refers to the passing of a person's genetic traits to the offspring of that person that includes recessive and dominant alleles. Reproduction is the process of creating viable, fertile offspring. This can be achieved via sexual or asexual methods. Natural selection can only occur when all these elements are in balance. If, for instance the dominant gene allele causes an organism reproduce and live longer than the recessive 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 be eliminated. The process is self reinforcing meaning that an organism that has an adaptive trait will live and reproduce much more than those with a maladaptive feature. The more offspring an organism produces, the greater its fitness, which is measured by its ability to reproduce itself and survive. Individuals with favorable traits, like a longer neck in giraffes or bright white color patterns in male peacocks are more likely to be able to survive and create offspring, so they will become the majority of the population in the future. Natural selection only affects populations, not individuals. This is a significant distinction from the Lamarckian theory of evolution, which states that animals acquire traits due to use or lack of use. For instance, if the Giraffe's neck grows longer due to stretching to reach for prey its offspring will inherit a larger neck. The difference in neck size between generations will continue to grow until the giraffe is unable to breed with other giraffes. Evolution through Genetic Drift Genetic drift occurs when alleles of a gene are randomly distributed in a group. Eventually, only one will be fixed (become common enough to no longer be eliminated through natural selection), and the rest of the alleles will decrease in frequency. In the extreme it can lead to dominance of a single allele. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small number of people this could result in the complete elimination of recessive alleles. This is known as the bottleneck effect. It is typical of the evolutionary process that occurs when a large number individuals migrate to form a population. A phenotypic bottleneck may happen when the survivors of a catastrophe, such as an epidemic or a massive hunting event, are condensed within a narrow area. The remaining individuals will be mostly homozygous for the dominant allele meaning that they all have the same phenotype, and thus share the same fitness characteristics. This situation might be caused by war, earthquake, or even a plague. Regardless of the cause, the genetically distinct population that remains could be prone to genetic drift. Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a “purely outcome-oriented” definition of drift as any deviation from the expected values of different fitness levels. They give a famous example of twins that are genetically identical, share identical phenotypes and yet one is struck by lightening and dies while the other lives and reproduces. This kind of drift can be crucial in the evolution of a species. It's not the only method for evolution. The primary alternative is a process called natural selection, where phenotypic variation in a population is maintained by mutation and migration. Stephens argues that there is a significant difference between treating the phenomenon of drift as a force, or an underlying cause, and considering other causes of evolution like mutation, selection and migration as causes or causes. He claims that a causal-process account of drift allows us distinguish it from other forces and that this distinction is crucial. He also argues that drift has an orientation, i.e., it tends to eliminate heterozygosity. It also has a size that is determined by population size. Evolution by Lamarckism When students in high school study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, commonly referred to as “Lamarckism” is based on the idea that simple organisms develop into more complex organisms by adopting traits that are a product of an organism's use and disuse. Lamarckism can be illustrated by an giraffe's neck stretching to reach higher leaves in the trees. This could cause the necks of giraffes that are longer to be passed to their offspring, who would then become taller. Lamarck was a French Zoologist. In his lecture to begin his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th May 1802, he presented an innovative concept that completely challenged the previous understanding of organic transformation. In his opinion living things had evolved from inanimate matter via a series of gradual steps. Lamarck was not the only one to suggest that this could be the case but his reputation is widely regarded as giving the subject its first broad and thorough treatment. The prevailing story is that Lamarckism became a rival to Charles Darwin's theory of evolution by natural selection and that the two theories battled each other in the 19th century. Darwinism ultimately prevailed which led to what biologists call the Modern Synthesis. This theory denies the possibility that acquired traits can be acquired through inheritance and instead argues that organisms evolve by the symbiosis of environmental factors, such as natural selection. Lamarck and his contemporaries endorsed the notion that acquired characters could be passed on to the next generation. However, this idea was never a central part of any of their theories on evolution. This is due to the fact that it was never tested scientifically. It's 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 also known as “neo Lamarckism”, or more generally epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model. Evolution through Adaptation One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle to survive. This view misrepresents natural selection and ignores the other forces that are driving evolution. 에볼루션게이밍 for survival is better described as a struggle to survive in a specific environment. This can include not only other organisms, but also the physical environment itself. To understand how evolution operates, it is helpful to consider what adaptation is. 바카라 에볼루션 “ refers to any specific feature 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 the heat or leaving at night to avoid cold. The ability of an organism to draw energy from its environment and interact with other organisms as well as their physical environments is essential to its survival. The organism must have the right genes to create offspring, and it should be able to find enough food and other resources. The organism should also be able reproduce itself at a rate that is optimal for its specific niche. These factors, together with gene flow and mutations can cause a shift in the proportion of different alleles within the gene pool of a population. Over time, this change in allele frequencies could result in the development of new traits and eventually new species. Many of the features that we admire in animals and plants are adaptations, like the lungs or gills that extract oxygen from the air, fur or feathers to protect themselves and long legs for running away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral traits. Physiological traits like the thick fur and gills are physical characteristics. The behavioral adaptations aren't like the tendency of animals to seek companionship or retreat into shade during hot weather. It is important to keep in mind that the absence of planning doesn't cause an adaptation. In fact, failure to think about the consequences of a decision can render it unadaptive even though it may appear to be logical or even necessary.