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What is Free Evolution? Free evolution is the concept that natural processes can cause organisms to develop over time. This includes the appearance and development of new species. A variety of examples have been provided of this, including various kinds of stickleback fish that can be found in salt or fresh water, and walking stick insect varieties that favor particular host plants. These reversible traits however, are not able to explain fundamental changes in body plans. Evolution by Natural Selection The evolution of the myriad living organisms on Earth is an enigma that has intrigued scientists for many centuries. Charles Darwin's natural selection theory is the most well-known explanation. This happens when those who are better adapted have more success in reproduction and survival than those who are less well-adapted. Over time, a population of well-adapted individuals expands and eventually forms a whole new species. Natural selection is a cyclical process that is characterized by the interaction of three elements 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 is the term used to describe the transmission of genetic characteristics, which includes both dominant and recessive genes to their offspring. Reproduction is the process of producing fertile, viable offspring which includes both sexual and asexual methods. All of these variables must be in harmony to allow natural selection to take place. If, for instance the dominant gene allele allows an organism to reproduce and last longer than the recessive gene, then the dominant allele becomes more prevalent in a population. But if the allele confers an unfavorable survival advantage or reduces fertility, it will be eliminated from the population. The process is self reinforcing, which means that an organism that has an adaptive trait will live and reproduce far more effectively than those with a maladaptive trait. The more offspring that an organism has, the greater its fitness, which is measured by its capacity to reproduce and survive. People with desirable traits, such as a longer neck in giraffes or bright white patterns of color in male peacocks are more likely to be able to survive and create offspring, so they will eventually make up the majority of the population over time. Natural selection only affects populations, not on individuals. This is a significant distinction from the Lamarckian evolution theory that states that animals acquire traits due to the use or absence of use. For instance, if a animal's neck is lengthened by stretching to reach prey and its offspring will inherit a longer neck. The differences in neck length between generations will continue until the giraffe's neck gets too long that it can not breed with other giraffes. Evolution through Genetic Drift In genetic drift, the alleles at a gene may be at different frequencies in a group through random events. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated by natural selection) and the other alleles drop in frequency. This could lead to a dominant allele at the extreme. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small group, this could lead to the total elimination of recessive alleles. This is known as the bottleneck effect. It is typical of the evolution process that occurs when an enormous number of individuals move to form a population. A phenotypic bottleneck may also occur when survivors of a disaster like an outbreak or mass hunt incident are concentrated in a small area. The remaining individuals are likely to be homozygous for the dominant allele, which means that they will all share the same phenotype and therefore have the same fitness characteristics. This can be caused by earthquakes, war or even a plague. The genetically distinct population, if it remains vulnerable to genetic drift. Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh, and Ariew use a “purely outcome-oriented” definition of drift as any deviation from expected values for variations in fitness. They provide a well-known instance of twins who are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces. This kind of drift could play a crucial part in the evolution of an organism. However, it's not the only method to develop. The main alternative is a process known as natural selection, in which phenotypic variation in an individual is maintained through mutation and migration. Stephens argues that there is a big distinction between treating drift as a force, or a cause and considering other causes of evolution, such as mutation, selection and migration as forces or causes. He claims that a causal mechanism account of drift permits us to differentiate it from these other forces, and this distinction is essential. He further argues that drift is both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined based on population size. Evolution by Lamarckism In high school, students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution is commonly called “Lamarckism” and it asserts that simple organisms evolve into more complex organisms through the inheritance of characteristics that are a result of the natural activities of an organism usage, use and disuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher leaves in the trees. This would cause the longer necks of giraffes to be passed to their offspring, who would then grow even taller. Lamarck, a French Zoologist, introduced a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. In his opinion living things evolved from inanimate matter through the gradual progression of events. 에볼루션 슬롯 was not the first to suggest that this might be the case but he is widely seen as giving the subject its first broad and comprehensive analysis. The prevailing story is that Lamarckism became an opponent to Charles Darwin's theory of evolution by natural selection and both theories battled each other in the 19th century. Darwinism ultimately won and led to what biologists call the Modern Synthesis. The Modern Synthesis theory denies that acquired characteristics can be inherited and instead suggests that organisms evolve through the action of environmental factors, including natural selection. While Lamarck endorsed the idea of inheritance through acquired characters and his contemporaries also offered a few words about this idea however, it was not an integral part of any of their theories about evolution. This is partly due to the fact that it was never validated scientifically. But it is now more than 200 years since Lamarck was born and in the age genomics there is a huge amount of evidence that supports the possibility of inheritance of acquired traits. This is sometimes called “neo-Lamarckism” or more often epigenetic inheritance. It is a form of evolution that is as valid as the more well-known neo-Darwinian model. Evolution through adaptation One of the most common misconceptions about evolution is its being driven by a fight for survival. In fact, this view is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The struggle for existence is better described as a fight to survive in a particular environment. This can be a challenge for not just other living things, but also the physical environment itself. Understanding the concept of adaptation is crucial to understand evolution. Adaptation refers to any particular characteristic that allows an organism to survive and reproduce in its environment. It could be a physical feature, like feathers or fur. Or it can be a behavior trait, like moving into the shade during hot weather or coming out to avoid the cold at night. The survival of an organism is dependent on its ability to obtain energy from the environment and interact with other organisms and their physical environments. The organism should possess the right genes for producing offspring and to be able to access sufficient food and resources. The organism should also be able to reproduce at an amount that is appropriate for its particular niche. These elements, along with gene flow and mutations, can lead to a shift in the proportion of different alleles in the gene pool of a population. As time passes, this shift in allele frequencies can lead to the emergence of new traits and eventually new species. Many of the features we find appealing in animals and plants are adaptations. For instance, lungs or gills that draw oxygen from air feathers and fur as insulation and long legs to get away from predators, and camouflage to hide. However, a proper understanding of adaptation requires paying attention to the distinction between physiological and behavioral characteristics. Physiological adaptations like thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to search for companions or to move to the shade during hot weather, are not. In addition, it is important to note that lack of planning does not make something an adaptation. In fact, a failure to consider the consequences of a decision can render it unadaptable, despite the fact that it might appear reasonable or even essential.