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What is Free Evolution? Free evolution is the idea that natural processes can cause organisms to develop over time. This includes the evolution of new species and change in appearance of existing species. A variety of examples have been provided of this, including different kinds of stickleback fish that can be found in salt or fresh water, and walking stick insect varieties that are attracted to particular host plants. These mostly reversible trait permutations can't, however, explain fundamental changes in body plans. Evolution by Natural Selection Scientists have been fascinated by the evolution of all living creatures that live on our planet for many centuries. Charles Darwin's natural selection theory is the most well-known explanation. This happens when people who are more well-adapted have more success in reproduction and survival than those who are less well-adapted. As time passes, a group of well-adapted individuals expands and eventually creates a new species. Natural selection is a process that is cyclical and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Mutation and sexual reproduction increase genetic diversity in the species. Inheritance refers to the transmission of a person’s genetic characteristics, which includes recessive and dominant genes to their offspring. 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 of these factors are in equilibrium. If, for example an allele of a dominant gene causes an organism reproduce and survive more than the recessive gene allele, then the dominant allele becomes more prevalent in a population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will disappear. This process is self-reinforcing meaning that a species that has a beneficial trait is more likely to survive and reproduce than an individual with an inadaptive characteristic. The more fit an organism is, measured by its ability reproduce and endure, is the higher number of offspring it can produce. People with desirable characteristics, such as the long neck of the giraffe, or bright white patterns on male peacocks, are more likely than others to survive and reproduce and eventually lead to them becoming the majority. Natural selection is an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which claims that animals acquire traits by use or inactivity. If a giraffe expands its neck to reach prey and its neck gets larger, then its offspring will inherit this trait. The length difference between generations will continue until the giraffe's neck becomes so long that it can not breed with other giraffes. Evolution through Genetic Drift In genetic drift, alleles within a gene can be at different frequencies in a group due to random events. Eventually, only one will be fixed (become common enough that it can no longer be eliminated through natural selection), and the other alleles drop in frequency. In extreme cases, this leads to one allele dominance. The other alleles are virtually eliminated and heterozygosity decreased to a minimum. In a small number of people, this could result in the complete elimination the recessive gene. This scenario is known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs when a lot of individuals migrate to form a new group. A phenotypic bottleneck can also happen when the survivors of a catastrophe, such as an epidemic or a massive hunting event, are condensed into a small area. The survivors will carry an dominant allele, and will share the same phenotype. This situation might be caused by conflict, earthquake or even a cholera outbreak. The genetically distinct population, if left, could be susceptible to genetic drift. Walsh, Lewens, and Ariew use Lewens, Walsh and Ariew employ a “purely outcome-oriented” definition of drift as any deviation from the expected values of variations in fitness. They give the famous example of twins who are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, whereas the other continues to reproduce. This kind of drift could be crucial in the evolution of the species. It's not the only method for evolution. The most common alternative is a process known as natural selection, where phenotypic variation in a population is maintained by mutation and migration. Stephens asserts that there is a huge difference between treating drift like an agent or cause and treating other causes like migration and selection mutation as causes and forces. He argues that a causal process explanation of drift permits us to differentiate it from other forces, and this distinction is vital. He further argues that drift is both an orientation, i.e., it tends to reduce heterozygosity. It also has a size, which is determined based on population size. Evolution by Lamarckism When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, often called “Lamarckism is based on the idea that simple organisms evolve into more complex organisms by taking on traits that are a product of an organism's use and disuse. Lamarckism is typically illustrated with a picture of a giraffe stretching its neck further to reach leaves higher up in the trees. This would cause the necks of giraffes that are longer to be passed to their offspring, who would then become taller. Lamarck Lamarck, a French zoologist, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. According Lamarck, living organisms evolved from inanimate materials by a series of gradual steps. 에볼루션 블랙잭 was not the first to suggest that this might be the case, but he is widely seen as having given the subject his first comprehensive and thorough treatment. The popular narrative is that Lamarckism grew into an opponent to Charles Darwin's theory of evolutionary natural selection and that the two theories battled 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 acquired characteristics can be acquired through inheritance and instead suggests that organisms evolve by the symbiosis of environmental factors, such as natural selection. Although Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries paid lip-service to this notion but it was not a major feature in 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 large amount of evidence to support the possibility of inheritance of acquired traits. This is often referred to as “neo-Lamarckism” or, more often, epigenetic inheritance. It is a variant of evolution that is as relevant as the more popular Neo-Darwinian theory. Evolution by adaptation One of the most common misconceptions about evolution is that it is driven by a type of struggle for survival. In fact, this view is inaccurate and overlooks the other forces that drive evolution. The struggle for survival is more precisely described as a fight to survive within a particular environment, which could be a struggle that involves not only other organisms but also the physical environment itself. Understanding adaptation is important to comprehend evolution. The term “adaptation” refers to any specific feature that allows an organism to survive and reproduce within its environment. It could be a physical feature, like feathers or fur. It could also be a trait of behavior such as moving towards shade during hot weather or escaping the cold at night. The survival of an organism is dependent on its ability to extract energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes to produce offspring and be able find enough food and resources. The organism should be able to reproduce itself at the rate that is suitable for its specific niche. These factors, together with mutation and gene flow can result in 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 can lead to the emergence of new traits, and eventually, new species in the course of time. A lot of the traits we admire in animals and plants are adaptations, for example, the lungs or gills that extract oxygen from the air, fur or feathers for insulation, long legs for running away from predators and camouflage to hide. To understand the concept of adaptation it is essential to differentiate between physiological and behavioral traits. Physiological traits like large gills and thick fur are physical characteristics. Behavior adaptations aren't like the tendency of animals to seek out companionship or move into the shade in hot weather. In addition it is important to remember that lack of planning does not make something an adaptation. Failure to consider the consequences of a decision even if it seems to be rational, may make it unadaptive.