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What is Free Evolution? Free evolution is the notion that natural processes can cause organisms to develop over time. This includes the appearance and growth of new species. Numerous examples have been offered of this, including different 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 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 evolution of all the living organisms that inhabit our planet for ages. The most well-known explanation is Darwin's natural selection process, an evolutionary process that occurs when individuals that are better adapted survive and reproduce more effectively than those who are less well-adapted. Over time, a community of well adapted individuals grows and eventually creates a new species. Natural selection is a cyclical process that involves the interaction of three elements including inheritance, variation, and reproduction. Sexual reproduction and mutations increase the genetic diversity of the species. Inheritance refers to the passing of a person's genetic characteristics to his or her offspring, which includes both dominant and recessive alleles. Reproduction is the process of generating viable, fertile offspring. This can be achieved by both asexual or sexual methods. Natural selection can only occur when all these elements are in harmony. For instance the case where a dominant allele at one gene can cause an organism to live and reproduce more often than the recessive allele the dominant allele will be more prominent in the population. However, 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 the organism with an adaptive characteristic will live and reproduce much more than those with a maladaptive trait. The higher the level of fitness an organism has as measured by its capacity to reproduce and survive, is the greater number of offspring it produces. People with desirable characteristics, like longer necks in giraffes and bright white color patterns in male peacocks are more likely survive and produce offspring, so they will eventually 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 a significant distinction from the Lamarckian evolution theory, which states that animals acquire traits either through the use or absence of use. If a giraffe extends its neck to reach prey, and the neck becomes larger, then its offspring will inherit this trait. The difference in neck size between generations will increase until the giraffe is unable to breed with other giraffes. Evolution by Genetic Drift In genetic drift, alleles at a gene may attain different frequencies within a population through random events. In the end, only one will be fixed (become common enough that it can no longer be eliminated through natural selection), and the rest of the alleles will drop in frequency. In the extreme this, it leads to one allele dominance. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small group, this could lead to the total elimination of recessive alleles. 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 survivors of a disaster such as an outbreak or mass hunt incident are concentrated in a small area. The surviving individuals are likely to be homozygous for the dominant allele, meaning that they all share the same phenotype and will thus have the same fitness characteristics. This may be caused by a war, earthquake, or even a plague. Regardless of the cause the genetically distinct population that remains could be susceptible to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a departure from the expected value due to differences in fitness. They give the famous example of twins that are genetically identical and have exactly the same phenotype. However, one is struck by lightning and dies, whereas the other is able to reproduce. This kind of drift could play a significant part in the evolution of an organism. It's not the only method of evolution. The primary alternative is a process called natural selection, in which the phenotypic variation of the population is maintained through mutation and migration. Stephens asserts that there is a significant difference between treating drift as a force or an underlying cause, and considering other causes of evolution such as selection, mutation and migration as causes 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 vital. He argues further 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 frequently introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution, commonly 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 illustrated through a giraffe extending its neck to reach 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 at the Museum of Natural History in Paris on 17 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 an escalating series of steps. Lamarck wasn't the only one to suggest this, but he was widely regarded as the first to give the subject a thorough and general overview. The prevailing story is that Lamarckism was a rival to Charles Darwin's theory of evolutionary natural selection, and that the two theories fought it out in the 19th century. Darwinism eventually triumphed, leading to the development of what biologists today refer to as the Modern Synthesis. The theory argues that traits acquired through evolution can be inherited and instead, it argues that organisms develop through the action of environmental factors, like natural selection. While Lamarck supported the notion of inheritance by acquired characters and his contemporaries spoke of this idea but it was not a major feature in any of their evolutionary theories. This is partly because it was never tested scientifically. However, it has been more than 200 years since Lamarck was born and in the age of genomics, there is a large amount of evidence that supports the possibility of inheritance of acquired traits. This is also referred to as “neo Lamarckism”, or more commonly epigenetic inheritance. It is a version of evolution that is as valid as the more popular Neo-Darwinian theory. Evolution through adaptation One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. This notion is not true and overlooks other forces that drive evolution. The struggle for existence is more accurately described as a struggle to survive in a particular environment. This could include not only other organisms, but also the physical environment. Understanding the concept of adaptation is crucial to understand evolution. It is a feature that allows living organisms to live in its environment and reproduce. It could be a physical structure like feathers or fur. It could also be a behavior trait, like moving to the shade during hot weather, or escaping the cold at night. The ability of an organism to extract energy from its surroundings and interact with other organisms and their physical environments is essential to its survival. The organism must have the right genes to create offspring and be able find enough food and resources. The organism must be able to reproduce at an amount that is appropriate for its specific niche. These factors, in conjunction with mutations and gene flow, can lead to a shift in the proportion of different alleles in the population's gene pool. This shift in the frequency of alleles can lead to the emergence of novel traits and eventually, new species in the course of time. 에볼루션 바카라 무료 of the characteristics we appreciate in animals and plants are adaptations. For instance lung or gills that extract oxygen from the air feathers and fur as insulation and long legs to get away from predators and camouflage to conceal. However, a proper understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral characteristics. Physiological traits like large gills and thick fur are physical characteristics. The behavioral adaptations aren't like the tendency of animals to seek companionship or retreat into shade during hot weather. Furthermore, it is important to understand that lack of planning does not make something an adaptation. Failure to consider the implications of a choice, even if it appears to be rational, could make it inflexible.