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What is Free Evolution? Free evolution is the concept that natural processes can lead to the development of organisms over time. This includes the evolution of new species and change in appearance of existing species. Many examples have been given of this, such as different kinds of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that prefer particular host plants. These are mostly reversible traits however, are not able to explain fundamental changes in basic body plans. Evolution through Natural Selection Scientists have been fascinated by the development of all the living creatures that inhabit our planet for many centuries. The most well-known explanation is Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well adapted. Over time, a community of well adapted individuals grows and eventually creates a new species. Natural selection is an ongoing process and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction both of which enhance 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 production of fertile, viable offspring, which includes both sexual and asexual methods. All of these factors must be in balance to allow natural selection to take place. For instance when a dominant allele at the gene can cause an organism to live and reproduce more frequently than the recessive allele the dominant allele will be more common in the population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will go away. The process is self-reinforcing, which means that an organism that has an adaptive trait will survive and reproduce much more than those with a maladaptive trait. The more offspring an organism produces the better its fitness that is determined by its ability to reproduce and survive. Individuals with favorable characteristics, like a longer neck in giraffes and bright white color patterns in male peacocks, are more likely to survive and have offspring, which means they will make up the majority of the population in the future. Natural selection is only an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution which argues that animals acquire traits through use or disuse. For example, if a animal's neck is lengthened by stretching to reach prey and its offspring will inherit a larger neck. The difference in neck size between generations will continue to increase until the giraffe is no longer able to breed with other giraffes. Evolution through Genetic Drift In genetic drift, the alleles of a gene could be at different frequencies within a population by chance events. Eventually, 에볼루션 of them will reach fixation (become so widespread that it is unable to be removed through natural selection) and other alleles will fall to lower frequency. This could lead to a dominant allele in the extreme. The other alleles are basically eliminated and heterozygosity has diminished to zero. In a small group this could result in the complete elimination of recessive allele. Such a scenario would be known as a bottleneck effect and it is typical of evolutionary process when a large number of individuals migrate to form a new group. A phenotypic bottleneck could happen when the survivors of a catastrophe, such as an epidemic or a massive hunting event, are condensed into a small area. The survivors will have a dominant allele and thus will have the same phenotype. This may be caused by conflict, earthquake, or even a plague. Whatever the reason the genetically distinct group that remains is susceptible to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a departure from the expected value due to differences in fitness. They provide a well-known instance of twins who are genetically identical and have identical phenotypes, and yet one is struck by lightning and dies, whereas the other lives and reproduces. This type of drift is crucial in the evolution of the species. It's not the only method for evolution. Natural selection is the main alternative, in which mutations and migrations maintain the phenotypic diversity in a population. Stephens asserts 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 such as mutation, selection and migration as forces or causes. He claims that a causal-process explanation of drift lets us differentiate it from other forces and that this distinction is crucial. He also claims that drift has a direction, that is it tends to reduce heterozygosity. He also claims that it also has a specific magnitude which is determined by population size. Evolution through 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, often referred to as “Lamarckism”, states that simple organisms transform into more complex organisms taking on traits that are a product of the organism's use and misuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher levels of leaves in the trees. This causes giraffes' longer necks to be passed to their offspring, who would then become taller. Lamarck Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. In his opinion, living things had evolved from inanimate matter through an escalating series of steps. Lamarck wasn't the first to suggest this however he was widely thought of as the first to provide the subject a comprehensive and general treatment. The popular narrative is that Lamarckism became a rival to Charles Darwin's theory of evolution through natural selection and both theories battled out in the 19th century. Darwinism ultimately prevailed and led to what biologists call the Modern Synthesis. The Modern Synthesis theory denies that acquired characteristics can be inherited and instead argues that organisms evolve through the selective action of environmental factors, including natural selection. Lamarck and his contemporaries endorsed the notion that acquired characters could be passed on to future generations. However, 에볼루션 바카라사이트 was never a key element of any of their theories about evolution. This is partly because it was never scientifically validated. 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 possibility of inheritance of acquired traits. This is sometimes 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 its being driven by a fight for survival. This view is inaccurate and ignores other forces driving evolution. The fight for survival can be more accurately described as a struggle to survive in a certain environment. This can include not just other organisms but also the physical environment. Understanding the concept of adaptation is crucial to comprehend evolution. It is a feature that allows a living organism to survive in its environment and reproduce. It could be a physical feature, such as feathers or fur. It could also be a behavior trait that allows you to move into the shade during hot weather, or coming 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. The organism must possess the right genes to produce offspring, and it should be able to find sufficient food and other resources. Moreover, the organism must be capable of reproducing itself at an optimal rate within its environment. These factors, along with gene flow and mutation can result in an alteration in the percentage of alleles (different varieties of a particular gene) in the population's gene pool. This shift in the frequency of alleles could lead to the development of new traits and eventually, new species in the course of time. Many of the characteristics we appreciate in plants and animals are adaptations. For instance lung or gills that extract oxygen from the air, fur and feathers as insulation long legs to run away from predators and camouflage for hiding. However, a complete understanding of adaptation requires attention to the distinction between the physiological and behavioral traits. Physiological adaptations, like thick fur or gills are physical traits, while behavioral adaptations, such as the desire to find friends or to move into the shade in hot weather, aren't. Additionally it is important to note that a lack of thought does not mean that something is an adaptation. Inability to think about the consequences of a decision even if it seems to be logical, can make it inflexible.