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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 growth of new species. 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 species that have a preference for specific host plants. These reversible traits, however, cannot explain fundamental changes in body plans. Evolution by Natural Selection Scientists have been fascinated by the evolution of all the living creatures that inhabit our planet for many centuries. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when people who are more well-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 becomes a new species. Natural selection is a cyclical process that is characterized by the interaction of three elements that are inheritance, variation and reproduction. Sexual reproduction and mutation increase genetic diversity in an animal species. Inheritance refers the transmission of a person’s genetic traits, which include both dominant and recessive genes to their offspring. Reproduction is the process of producing fertile, viable offspring, which includes both sexual and asexual methods. Natural selection is only possible when all these elements are in equilibrium. For instance the case where an allele that is dominant at the gene allows an organism to live and reproduce more frequently than the recessive allele the dominant allele will become more prevalent within the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will go away. The process is self reinforcing, which means that the organism with an adaptive trait will survive and reproduce much more than one with a maladaptive characteristic. The higher the level of fitness an organism has as measured by its capacity to reproduce and survive, is the more offspring it produces. People with good traits, such as a longer neck in giraffes, or bright white colors in male peacocks are more likely survive and produce offspring, which means they will become the majority of the population in the future. Natural selection only affects populations, not individual organisms. This is a major distinction from the Lamarckian theory of evolution, which argues that animals acquire characteristics through use or neglect. For example, if a animal's neck is lengthened by reaching out to catch prey and its offspring will inherit a more long neck. The length difference between generations will continue until the giraffe's neck gets so long that it can not breed with other giraffes. Evolution through Genetic Drift Genetic drift occurs when alleles of a gene are randomly distributed in a group. At some point, only one of them will be fixed (become widespread enough to not more be eliminated through natural selection) and the rest of the alleles will drop in frequency. This can result in an allele that is dominant at the extreme. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In 무료 에볼루션 could result in the complete elimination of recessive allele. This scenario is called the bottleneck effect and is typical of an evolutionary process that occurs when a large number individuals migrate to form a group. A phenotypic bottleneck may also occur when the survivors of a catastrophe such as an outbreak or mass hunting event are confined to a small 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 can be caused by earthquakes, war or even plagues. 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 departure from the expected values of different fitness levels. They cite a famous example of twins that are genetically identical, share identical phenotypes and yet one is struck by lightning and dies, whereas the other lives and reproduces. 에볼루션 바카라 체험 of drift can be crucial in the evolution of an entire species. This isn't the only method for evolution. Natural selection is the main alternative, in which mutations and migration maintain the phenotypic diversity of a population. Stephens asserts that there is a vast distinction between treating drift as a force or cause, and treating other causes such as selection mutation and migration as causes and forces. He argues that a causal-process account of drift allows us distinguish it from other forces, and this differentiation is crucial. He also argues that drift has a direction: that is, it tends to eliminate heterozygosity, and that it also has a size, that is determined by the size of population. Evolution by Lamarckism Students of biology in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, also referred to as “Lamarckism” is based on the idea that simple organisms develop into more complex organisms through adopting traits that are a product of the use and abuse of an organism. Lamarckism is typically illustrated by a picture of a giraffe that extends its neck to reach higher up in the trees. This would cause the necks of giraffes that are longer to be passed on to their offspring who would then grow even taller. Lamarck Lamarck, a French Zoologist, introduced an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. In his view, living things had evolved from inanimate matter through a series of gradual steps. Lamarck was not the only one to suggest that this might be the case but the general consensus is that he was the one being the one who gave the subject its first general and thorough treatment. The most popular story is that Lamarckism became an opponent to Charles Darwin's theory of evolution through natural selection, and that the two theories fought each other in the 19th century. Darwinism eventually prevailed which led to what biologists refer to as the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead argues that organisms evolve through the influence of environment factors, including Natural Selection. While Lamarck supported the notion of inheritance by acquired characters, and his contemporaries also spoke of this idea, it was never a major feature in any of their theories about evolution. This is largely 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 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 often, epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model. Evolution through Adaptation One of the most common misconceptions about evolution is its being driven by a struggle to survive. In fact, this view misrepresents natural selection and ignores the other forces that are driving evolution. The struggle for survival is more accurately described as a struggle to survive within a specific environment, which can be a struggle that involves not only other organisms, but also the physical environment. Understanding adaptation is important to understand evolution. The term “adaptation” refers to any characteristic that allows living organisms to survive in its environment and reproduce. It can be a physical structure, like feathers or fur. Or it can be a trait of behavior such as moving to the shade during the heat, or escaping the cold at night. The ability of an organism to extract energy from its surroundings and interact with other organisms as well as their physical environment is essential to its survival. The organism should possess the right genes to create offspring and to be able to access sufficient food and resources. The organism must also be able to reproduce itself at a rate that is optimal for its niche. These elements, in conjunction with gene flow and mutation, lead to changes in the ratio of alleles (different varieties of a particular gene) in a population's gene pool. This shift in the frequency of alleles could lead to the development of new traits, and eventually, new species over time. A lot of the traits we admire in animals and plants are adaptations, like lung or gills for removing oxygen from the air, fur or feathers to provide insulation, long legs for running away from predators and camouflage for hiding. To understand the concept of adaptation it is crucial to discern between physiological and behavioral traits. Physical characteristics like large gills and thick fur are physical characteristics. Behavioral adaptations are not like the tendency of animals to seek out companionship or retreat into shade in hot weather. It is also important to note that lack of planning does not result in an adaptation. In fact, failing to consider the consequences of a decision can render it unadaptive, despite the fact that it might appear sensible or even necessary.