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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 evolution of new species as well as the transformation of the appearance of existing ones. This is evident in many examples such as the stickleback fish species that can be found in saltwater or fresh water and walking stick insect types that prefer specific host plants. These reversible traits can't, however, explain fundamental changes in basic body plans. Evolution through Natural Selection The development of the myriad of living creatures on Earth is an enigma that has intrigued scientists for many centuries. Charles Darwin's natural selectivity is the best-established explanation. This process occurs when people who are more well-adapted survive and reproduce more than those who are less well-adapted. Over time, the population of well-adapted individuals becomes larger and eventually forms a new species. Natural selection is a process that is cyclical and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutations 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 process of generating viable, fertile offspring. This can be done by both asexual or sexual methods. Natural selection is only possible when all these elements are in equilibrium. If, for instance, a dominant gene allele causes an organism reproduce and live longer than the recessive gene allele, then the dominant allele will become more prevalent in a group. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will disappear. The process is self-reinforced, meaning that a species with a beneficial characteristic is more likely to survive and reproduce than an individual with an unadaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and endure, is the higher number of offspring it produces. People with desirable traits, such as having a longer neck in giraffes or bright white colors in male peacocks are more likely to survive and produce offspring, which means they will make up the majority of the population in the future. Natural selection is only an element in the population and not on individuals. This is an important distinction from the Lamarckian theory of evolution which claims that animals acquire traits through use or neglect. For instance, if a Giraffe's neck grows longer due to reaching out to catch prey and its offspring will inherit a more long neck. The differences in neck size between generations will increase until the giraffe becomes unable to reproduce with other giraffes. Evolution through Genetic Drift In genetic drift, alleles of a gene could attain different frequencies in a population by chance events. At some point, only one of them will be fixed (become widespread enough to not more be eliminated through natural selection) and the other alleles will drop in frequency. This can result in a dominant allele in extreme. The other alleles are eliminated, and heterozygosity decreases to zero. In a small group this could result in the total elimination of the recessive allele. This is known as the bottleneck effect. It is typical of the evolutionary process that occurs when the number of individuals migrate to form a population. A phenotypic bottleneck may occur when the survivors of a disaster, such as an epidemic or a mass hunting event, are concentrated in a limited area. The surviving individuals are likely to be homozygous for the dominant allele which means that they will all share the same phenotype, and thus have the same fitness traits. This situation could be caused by war, earthquakes, or even plagues. Regardless of the cause the genetically distinct group that remains could be susceptible to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a departure from expected values due to differences in fitness. They cite the famous example of twins who are genetically identical and have exactly the same phenotype. However, one is struck by lightning and dies, whereas the other continues to reproduce. This kind of drift can play a crucial role in the evolution of an organism. It's not the only method of evolution. Natural selection is the primary alternative, where mutations and migrations maintain the phenotypic diversity of a population. Stephens claims that there is a major difference between treating the phenomenon of drift as a force, or a cause and considering other causes of evolution, such as mutation, selection and migration as causes or causes. Stephens claims that a causal process explanation of drift lets us differentiate it from other forces, and this distinction is crucial. He further argues that drift has a direction, i.e., it tends to reduce heterozygosity. It also has a size which is determined by population size. Evolution by Lamarckism Students of biology in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, often referred to as “Lamarckism” which means that simple organisms transform into more complex organisms through inheriting characteristics that are a product of an organism's use and disuse. Lamarckism is typically illustrated by the image of a giraffe that extends its neck to reach higher up in the trees. This would cause giraffes to give their longer necks to their offspring, which then grow even taller. Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to Lamarck, living creatures evolved from inanimate material by a series of gradual steps. Lamarck was not the first to make this claim however he was widely considered to be the first to give the subject a thorough and general treatment. The most popular story is that Charles Darwin's theory on natural selection and Lamarckism fought in the 19th century. Darwinism eventually triumphed and led to the development of what biologists now call the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead, it claims that organisms evolve through the influence of environment factors, including Natural Selection. Although Lamarck supported the notion of inheritance through acquired characters and his contemporaries offered a few words about this idea but it was not a central element in any of their theories about evolution. This is due to the fact that it was never scientifically tested. It's been more than 200 years since Lamarck was born and, in the age of genomics, there is a large body of evidence supporting the heritability of acquired characteristics. This is sometimes referred to as “neo-Lamarckism” or, more frequently, epigenetic inheritance. It is a version of evolution that is as valid as the more well-known neo-Darwinian model. Evolution by Adaptation One of the most common misconceptions about evolution is that it is driven by a type of struggle to survive. This view is inaccurate and overlooks other forces that drive evolution. The struggle for survival is more effectively described as a struggle to survive in a specific environment, which can involve not only other organisms but as well the physical environment. Understanding how adaptation works is essential to understand evolution. Adaptation is any feature that allows living organisms to survive in its environment and reproduce. visit the next internet site can be a physiological structure such as feathers or fur or a behavioral characteristic, such as moving to the shade during the heat or leaving at night to avoid cold. The capacity of an organism to extract energy from its environment and interact with other organisms, as well as their physical environments, is crucial to its survival. The organism needs to have the right genes to produce offspring, and it must be able to locate sufficient food and other resources. The organism must also be able to reproduce at an amount that is appropriate for its niche. These factors, together with mutations and gene flow can result in an alteration in the ratio of different alleles within the gene pool of a population. This shift in the frequency of alleles can result in the emergence of novel traits and eventually new species in the course of time. Many of the features we find appealing in animals and plants are adaptations. For instance lung or gills that extract oxygen from air, fur and feathers as insulation, long legs to run away from predators and camouflage for hiding. To comprehend adaptation it is crucial to differentiate between physiological and behavioral traits. Physical traits such as large gills and thick fur are physical traits. The behavioral adaptations aren't like the tendency of animals to seek companionship or to retreat into the shade during hot temperatures. Additionally, it is important to understand that lack of planning is not a reason to make something an adaptation. Failure to consider the implications of a choice, even if it appears to be rational, may cause it to be unadaptive.