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What is Free Evolution? Free evolution is the idea that the natural processes of organisms can lead them to evolve over time. This includes the creation of new species and the alteration of the appearance of existing ones. Many examples have been given of this, including various varieties of fish called sticklebacks that can live in either salt or fresh water, and walking stick insect varieties that prefer particular host plants. These 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 organisms that inhabit our planet for ages. The most well-known explanation is Charles Darwin's natural selection, which 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 creates a new species. Natural selection is an ongoing process that involves the interaction of three factors including inheritance, variation, and reproduction. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity within a species. Inheritance is the term used to describe the transmission of a person's genetic characteristics, which includes recessive and dominant genes, to their offspring. Reproduction is the process of creating viable, fertile offspring. This can be done by both asexual or sexual methods. Natural selection can only occur when all of these factors are in harmony. If, for example, a dominant gene allele makes an organism reproduce and survive more than the recessive allele The dominant allele becomes more prevalent in a group. However, if the gene confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. The process is self-reinforcing which means that the organism with an adaptive trait will live and reproduce more quickly than those with a maladaptive feature. The more offspring an organism produces, the greater its fitness which is measured by its ability to reproduce and survive. People with good characteristics, such as the long neck of giraffes, or bright white color patterns on male peacocks, are more likely than others to live and reproduce which eventually leads to them becoming the majority. Natural selection is only a force for populations, not on individuals. This is an important distinction from the Lamarckian theory of evolution which claims that animals acquire characteristics through use or neglect. For instance, if a giraffe's neck gets longer through reaching out to catch prey its offspring will inherit a larger neck. The differences in neck size between generations will continue to increase until the giraffe is no longer able to breed with other giraffes. Evolution by Genetic Drift Genetic drift occurs when the alleles of one gene are distributed randomly in a group. At some point, one will attain fixation (become so common that it can no longer be eliminated through natural selection), while other alleles will fall to lower frequency. This can lead to a dominant allele in the extreme. The other alleles have been basically eliminated and heterozygosity has been reduced to a minimum. In a small group this could lead to the complete elimination of the recessive gene. This scenario is called the bottleneck effect. It is typical of an evolution process that occurs when the number of individuals migrate to form a group. A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe such as an outbreak or mass hunt event are confined to a small area. The survivors will have an dominant allele, and will have the same phenotype. This could be caused by war, earthquakes or even plagues. The genetically distinct population, if left vulnerable to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a departure from expected values 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 kind of drift can be vital to the evolution of a species. But, it's not the only way to evolve. The main alternative is a process called natural selection, in which phenotypic variation in a population is maintained by mutation and migration. Stephens asserts that there is a significant difference between treating the phenomenon of drift as a force or as a cause and treating other causes of evolution, such as mutation, selection and migration as forces or causes. Stephens claims that a causal process account of drift allows us to distinguish it from these other forces, and that this distinction is essential. He argues further that drift has an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined based on the size of the population. Evolution by Lamarckism Students of biology in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, commonly referred to as “Lamarckism, states that simple organisms evolve into more complex organisms through inheriting characteristics that result from an organism's use and disuse. Lamarckism is usually illustrated with a picture of a giraffe stretching its neck longer to reach the higher branches in the trees. This could cause the longer necks of giraffes to be passed to their offspring, who would grow taller. Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th May 1802, he introduced an original idea that fundamentally challenged previous thinking about organic transformation. In his view living things had evolved from inanimate matter via a series of gradual steps. Lamarck wasn't the only one to propose this however he was widely regarded as the first to offer the subject a thorough and general treatment. The dominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were rivals in the 19th century. Darwinism ultimately won and led to what biologists refer to as the Modern Synthesis. This theory denies acquired characteristics can be passed down and instead argues that organisms evolve through the selective influence of environmental factors, including Natural Selection. While Lamarck supported the notion of inheritance by acquired characters, and his contemporaries also offered a few words about this idea but it was not an integral part of any of their evolutionary theories. This is due to the fact that it was never tested scientifically. But it is now more than 200 years since Lamarck was born and in the age genomics there is a huge body of evidence supporting the heritability of acquired characteristics. This is also referred to as “neo Lamarckism”, or more commonly epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model. Evolution by the process of adaptation One of the most commonly-held misconceptions about evolution is that it is being driven by a struggle to survive. This notion is not true 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 may be a struggle that involves not only other organisms but also the physical environment itself. To understand how evolution works, it is helpful to think about what adaptation is. It is a feature that allows a living organism to live in its environment and reproduce. It could be a physical structure like feathers or fur. It could also be a characteristic of behavior that allows you to move towards shade during the heat, or moving out to avoid the cold at night. The ability of a living thing to extract energy from its environment and interact with other organisms and their physical environments, is crucial to its survival. 무료 에볼루션 must have the right genes to generate offspring, and it should be able to find enough food and other resources. The organism should also be able to reproduce at an amount that is appropriate for its niche. These factors, in conjunction with gene flow and mutations can cause a shift in the proportion of different alleles in the population's gene pool. As time passes, this shift in allele frequency can result in the development of new traits and ultimately new species. Many of the characteristics we admire in plants and animals are adaptations. For example, lungs or gills that draw oxygen from air feathers and fur for insulation, long legs to run away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires paying attention to the distinction between the physiological and behavioral traits. Physiological adaptations, like the thick fur or gills are physical traits, whereas behavioral adaptations, such as the tendency to seek out friends or to move to the shade during hot weather, aren't. It is also important to note that lack of planning does not make an adaptation. A failure to consider the implications of a choice, even if it appears to be logical, can make it unadaptive.