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What is Free Evolution? Free evolution is the concept that the natural processes of living organisms can lead to their development over time. This includes the appearance and growth of new species. A variety of examples have been provided of this, including various kinds of stickleback fish that can live in salt or fresh water, and walking stick insect varieties that are attracted to particular host plants. These reversible traits however, are not able to be the reason for fundamental changes in body plans. Evolution by Natural Selection The evolution of the myriad living organisms on Earth is a mystery that has fascinated scientists for decades. The best-established explanation is that of Charles Darwin's natural selection process, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those who are less well adapted. As time passes, a group of well adapted individuals grows and eventually becomes a new species. Natural selection is an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity of the species. Inheritance is the transfer of a person's genetic traits to their offspring, which includes both dominant and recessive alleles. Reproduction is the production of viable, fertile offspring, which includes both asexual and sexual methods. Natural selection is only possible when all of these factors are in harmony. For example the case where the dominant allele of one gene allows an organism to live and reproduce more frequently than the recessive one, the dominant allele will become more common in the population. But if the allele confers an unfavorable survival advantage or decreases fertility, it will be eliminated from the population. The process is self reinforcing meaning that an organism that has an adaptive trait will survive and reproduce much more than those with a maladaptive feature. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with good characteristics, such as having a long neck in giraffes, or bright white color patterns on male peacocks are more likely to others to reproduce and survive, which will eventually lead to them becoming the majority. Natural selection is only a factor in populations and not on individuals. This is a crucial distinction from the Lamarckian theory of evolution, which states that animals acquire traits due to use or lack of use. If a giraffe stretches its neck to reach prey and its neck gets larger, then its children will inherit this characteristic. The difference in neck length between generations will persist until the giraffe's neck becomes too long that it can no longer breed with other giraffes. Evolution through Genetic Drift In the process of genetic drift, alleles within a gene can reach different frequencies within a population due to random events. At some point, only one of them will be fixed (become common enough to no longer be eliminated through natural selection), and the other alleles will diminish in frequency. This can lead to dominance in the extreme. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small number of people, this could result in the complete elimination of recessive gene. This scenario is called the bottleneck effect and is typical of an evolution process that occurs when the number of individuals migrate to form a population. A phenotypic bottleneck can also occur when survivors of a disaster like an epidemic or a mass hunting event, are concentrated within a narrow area. The survivors will be mostly homozygous for the dominant allele which means that they will all share the same phenotype and consequently have the same fitness characteristics. This can be caused by earthquakes, war, or even plagues. Whatever the reason the genetically distinct group that remains is prone to genetic drift. Walsh Lewens, Walsh, and Ariew define drift as a departure from expected values due to differences in fitness. They cite a famous example of twins that are genetically identical, have identical phenotypes, but one is struck by lightning and dies, whereas the other lives and reproduces. This kind of drift could be very important in the evolution of an entire species. But, it's not the only method to evolve. The most common alternative is a process known as natural selection, in which phenotypic variation in the population is maintained through mutation and migration. Stephens asserts that there is a huge difference between treating drift like a force or cause, and treating other causes such as migration and selection as forces and causes. He claims that a causal mechanism account of drift permits us to differentiate it from these other forces, and that this distinction is vital. He argues further that drift has both an orientation, i.e., it tends to eliminate heterozygosity. It also has a size which is determined based on population size. Evolution through Lamarckism Biology students in high school are frequently introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution is generally known as “Lamarckism” and it asserts that simple organisms evolve into more complex organisms by the inheritance of traits that are a result of an organism's natural activities, use and disuse. Lamarckism is typically illustrated by an image of a giraffe stretching its neck further to reach leaves higher up in the trees. This process would cause giraffes to pass on their longer necks to their offspring, who would then grow even taller. Lamarck Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According to him living things had evolved from inanimate matter through a series of gradual steps. Lamarck wasn't the first to propose this, but he was widely thought of as the first to give the subject a thorough and general overview. The prevailing story is that Lamarckism became a rival to Charles Darwin's theory of evolution through natural selection, and that the two theories battled out in the 19th century. Darwinism eventually won and led to the development of what biologists today refer to as the Modern Synthesis. This theory denies acquired characteristics can be passed down through generations and instead argues that organisms evolve through the selective influence of environmental factors, such as Natural Selection. Although Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries offered a few words about this idea however, it was not a central element in any of their evolutionary theories. This is due to the fact that it was never scientifically tested. It's been over 200 year since Lamarck's birth, and in the age genomics, there is a growing evidence base that supports the heritability-acquired characteristics. This is sometimes referred to as “neo-Lamarckism” or, more frequently, epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model. Evolution through Adaptation One of the most popular misconceptions about evolution is being driven by a struggle to survive. In reality, this notion is inaccurate and overlooks the other forces that are driving evolution. The fight for survival is more accurately described as a struggle to survive in a specific environment. This can include not just other organisms but also the physical surroundings themselves. Understanding adaptation is important to comprehend evolution. Adaptation refers to any particular feature that allows an organism to survive and reproduce within its environment. It could be a physical feature, like feathers or fur. Or it can be a trait of behavior such as moving 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 surroundings and interact with other organisms as well as their physical environment, is crucial to its survival. 에볼루션 슬롯게임 must possess the right genes to create offspring, and must be able to locate sufficient food and other resources. The organism must also be able reproduce at an amount that is appropriate for its specific niche. These factors, together with mutations and gene flow can result in changes in the proportion of different alleles in a population’s gene pool. Over time, this change in allele frequencies could result in the emergence of new traits, and eventually new species. Many of the features we admire in animals and plants are adaptations. For instance the lungs or gills which extract oxygen from air feathers and fur for insulation long legs to run away from predators and camouflage for hiding. To understand adaptation it is essential to discern 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 shade in hot weather, aren't. Additionally it is important to remember that a lack of forethought does not mean that something is an adaptation. In fact, failure to consider the consequences of a behavior can make it unadaptable even though it might appear sensible or even necessary.