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What is Free Evolution? 에볼루션 무료 바카라 is the concept that the natural processes of living organisms can lead them to evolve over time. This includes the appearance and growth of new species. Many examples have been given of this, including different kinds of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that prefer particular host plants. These reversible traits can't, however, be the reason for fundamental changes in body plans. Evolution through Natural Selection Scientists have been fascinated by the evolution of all living organisms that inhabit our planet for centuries. Charles Darwin's natural selectivity is the most well-known explanation. This happens when those who are better adapted survive and reproduce more than those who are less well-adapted. As time passes, the number of well-adapted individuals grows and eventually creates an entirely 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 within an animal species. Inheritance is the passing of a person's genetic traits to their offspring that includes recessive and dominant alleles. Reproduction is the process of producing viable, fertile offspring, which includes both asexual and sexual methods. All of these factors have to be in equilibrium to allow natural selection to take place. For instance when a dominant allele at one gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will be more prevalent in the population. However, if the allele confers a disadvantage in survival or reduces 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 far more effectively than those with a maladaptive feature. The more offspring that an organism has the more fit it is which is measured by its capacity to reproduce and survive. People with desirable traits, like having a longer neck in giraffes and bright white colors in male peacocks are more likely be able to survive and create offspring, and thus will eventually make up the majority of the population over time. Natural selection is an aspect of populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution, which claims that animals acquire characteristics by use or inactivity. For instance, if the Giraffe's neck grows longer due to stretching to reach for prey, its offspring will inherit a larger neck. The length difference between generations will continue until the giraffe's neck gets too long that it can no longer breed with other giraffes. Evolution through Genetic Drift In genetic drift, the alleles of a gene could attain different frequencies in a population by chance events. At some point, one will reach fixation (become so common that it is unable to be eliminated by natural selection), while the other alleles drop to lower frequencies. In extreme cases, this leads to dominance of a single allele. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small population it could lead to the complete elimination of recessive alleles. This is known as the bottleneck effect. It is typical of the evolution process that occurs when a large number individuals migrate to form a group. A phenotypic bottleneck can also occur when the survivors of a catastrophe, such as an epidemic or mass hunt, are confined into a small area. The survivors are likely to be homozygous for the dominant allele which means that they will all have the same phenotype and consequently have the same fitness characteristics. This situation might be caused by a conflict, earthquake, or even a plague. Whatever the reason the genetically distinct group that is left might be prone to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a departure from expected values due to differences in fitness. They give a famous instance of twins who are genetically identical and have identical phenotypes, but one is struck by lightning and dies, while the other lives and reproduces. This type of drift is vital to the evolution of a species. This isn't the only method of evolution. The main alternative is a process called natural selection, where phenotypic variation in the population is maintained through mutation and migration. Stephens argues there is a significant difference between treating drift like an agent or cause and treating other causes like selection mutation and migration as causes and forces. He argues that a causal-process model of drift allows us to distinguish it from other forces, and this distinction is crucial. He also claims that drift has a direction, that is it tends to reduce heterozygosity, and that it also has a specific magnitude that is determined by the size of population. Evolution through Lamarckism Biology students in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is generally called “Lamarckism” and it states that simple organisms grow into more complex organisms by the inherited characteristics which result from the organism's natural actions use and misuse. Lamarckism is typically illustrated by a picture of a giraffe extending its neck further to reach leaves higher up in the trees. This process would cause giraffes to pass on their longer necks to offspring, which then get taller. Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate zoology at the Museum of Natural History in Paris on the 17th May 1802, he introduced an original idea that fundamentally challenged previous thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate material through a series of gradual steps. Lamarck was not the first to suggest that this might be the case but he is widely seen as being the one who gave the subject its first broad and thorough treatment. The most popular story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection, and that the two theories fought it out in the 19th century. Darwinism ultimately won, leading to what biologists call the Modern Synthesis. The theory argues the possibility that acquired traits can be acquired through inheritance and instead suggests that organisms evolve through the selective action of environmental factors, like natural selection. Lamarck and his contemporaries endorsed the idea that acquired characters could be passed down to future generations. However, this notion was never a major part of any of their theories about evolution. This is due to the fact that it was never scientifically validated. It's been more than 200 years since Lamarck was born and, in the age of genomics there is a huge amount of evidence that supports the heritability of acquired traits. This is sometimes referred to as “neo-Lamarckism” or more often, epigenetic inheritance. It is a version of evolution that is just as valid as the more popular neo-Darwinian model. Evolution by the process of adaptation One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. This view is a misrepresentation of natural selection and ignores the other forces that are driving evolution. The fight for survival can be more effectively described as a struggle to survive in a specific environment, which may be a struggle that involves not only other organisms but also the physical environment itself. To understand how evolution works it is important to think about what adaptation is. The term “adaptation” refers to any specific characteristic that allows an organism to live and reproduce within its environment. It could be a physical feature, like feathers or fur. Or it can be a characteristic of behavior, like moving into the shade during hot weather or coming out to avoid the cold at night. The capacity of an organism to draw energy from its surroundings and interact with other organisms as well as their physical environments, is crucial to its survival. The organism must possess the right genes to produce offspring and be able find enough food and resources. In addition, the organism should be capable of reproducing itself in a way that is optimally within its environmental niche. These factors, together with mutations and gene flow can result in changes in the proportion of different alleles in the gene pool of a population. This shift in the frequency of alleles can lead to the emergence of new traits and eventually, new species as time passes. A lot of the traits we admire in animals and plants are adaptations. For example lung or gills that draw oxygen from air feathers and fur for insulation, long legs to run away from predators and camouflage to conceal. However, a thorough understanding of adaptation requires attention to the distinction between the physiological and behavioral traits. Physiological traits like thick fur and gills are physical traits. The behavioral adaptations aren't, such as the tendency of animals to seek out companionship or retreat into shade in hot weather. Furthermore it is important to remember that a lack of thought is not a reason to make something an adaptation. In fact, failing to think about the consequences of a choice can render it unadaptable despite the fact that it may appear to be reasonable or even essential.