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What is Free Evolution? Free evolution is the notion that natural processes can cause organisms to evolve over time. This includes the evolution of new species and transformation of the appearance of existing ones. Many examples have been given of this, including various kinds of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that prefer specific host plants. These reversible traits cannot explain fundamental changes to basic body plans. Evolution by Natural Selection Scientists have been fascinated by the evolution of all the living organisms that inhabit our planet for ages. Charles Darwin's natural selection is the best-established explanation. This process occurs when people who are more well-adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, a population of well-adapted individuals increases and eventually becomes a new species. Natural selection is a cyclical process that is characterized by the interaction of three elements: variation, inheritance and reproduction. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within a species. Inheritance is the transfer of a person's genetic characteristics to their offspring which includes both recessive and dominant alleles. Reproduction is the process of generating viable, fertile offspring. This can be done via sexual or asexual methods. Natural selection can only occur when all these elements are in balance. For example, if an allele that is dominant at one gene allows an organism to live and reproduce more frequently than the recessive allele, the dominant allele will become more prevalent within the population. However, if the gene confers a disadvantage in survival or decreases fertility, it will disappear from the population. This process is self-reinforcing which means that an organism with a beneficial characteristic is more likely to survive and reproduce than an individual with an unadaptive characteristic. The more offspring that an organism has the more fit it is which is measured by its ability to reproduce and survive. Individuals with favorable characteristics, like having a longer neck in giraffes and bright white patterns of color in male peacocks, are more likely to survive and produce offspring, and thus will become the majority of the population in the future. Natural selection is only a factor in populations and not on individuals. This is a crucial distinction from the Lamarckian evolution theory that states that animals acquire traits due to usage or inaction. For instance, if the giraffe's neck gets longer through stretching to reach for prey and its offspring will inherit a larger neck. The differences in neck length between generations will persist until the giraffe's neck gets too long that it can not breed with other giraffes. Evolution by Genetic Drift Genetic drift occurs when alleles from the same gene are randomly distributed within a population. In the end, only one will be fixed (become common enough that it can no longer be eliminated by natural selection), and the other alleles will decrease in frequency. This can lead to a dominant allele in extreme. The other alleles have been virtually eliminated and heterozygosity diminished to a minimum. In a small population it could lead to the complete elimination of the recessive allele. Such a scenario would be known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs when a large number of people migrate to form a new 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 survivors will share a dominant allele and thus will share the same phenotype. This situation could be caused by war, earthquakes, or even plagues. The genetically distinct population, if it is left, could be susceptible to genetic drift. Walsh Lewens, Lewens, and Ariew utilize a “purely outcome-oriented” definition of drift as any deviation from expected values for variations in fitness. 에볼루션 사이트 provide the famous case of twins who are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, whereas the other is able to reproduce. This kind of drift can be very important in the evolution of an entire species. However, it's not the only method to develop. Natural selection is the main alternative, where mutations and migration keep the phenotypic diversity of a population. Stephens argues that there is a significant difference between treating the phenomenon of drift as a force or a cause and treating other causes of evolution like selection, mutation and migration as causes or causes. He argues that a causal-process model of drift allows us to separate it from other forces and this differentiation is crucial. He argues further that drift is both a direction, i.e., it tends to eliminate heterozygosity. It also has a size which is determined based on the size of the population. Evolution through Lamarckism Biology students in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is commonly known as “Lamarckism” and it asserts that simple organisms evolve into more complex organisms by the inherited characteristics which result from the organism's natural actions, use and disuse. Lamarckism is typically illustrated by the image of a giraffe stretching its neck longer to reach leaves higher up in the trees. This would cause giraffes to pass on their longer necks to their offspring, who then get taller. Lamarck Lamarck, a French Zoologist from France, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the conventional wisdom on organic transformation. According to Lamarck, living things evolved from inanimate materials through a series 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 broad and comprehensive analysis. The dominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism fought during the 19th century. Darwinism ultimately prevailed and led to what biologists refer to as the Modern Synthesis. The theory argues the possibility that acquired traits can be acquired through inheritance and instead argues that organisms evolve through the selective action of environmental factors, such as natural selection. Lamarck and his contemporaries endorsed the notion that acquired characters could be passed on to the next generation. However, this concept was never a major part of any of their theories about evolution. This is due in part to the fact that it was never tested scientifically. It has been more than 200 year since Lamarck's birth, and in the age genomics, there is an increasing evidence-based body of evidence to support the heritability-acquired characteristics. This is also referred to as “neo Lamarckism”, or more often epigenetic inheritance. It is a form of evolution that is as valid as the more popular Neo-Darwinian model. Evolution by Adaptation One of the most common misconceptions about evolution is its being driven by a struggle to survive. In reality, this notion is inaccurate and overlooks the other forces that determine the rate of evolution. The struggle for survival is more precisely described as a fight to survive within a specific environment, which could involve not only other organisms but also the physical environment. To understand how evolution works, it is helpful to consider what adaptation is. It is a feature that allows a living organism to live in its environment and reproduce. It could be a physiological structure, like feathers or fur, or a behavioral trait like moving into the shade in hot weather or stepping out at night to avoid cold. The survival of an organism is dependent on its ability to obtain energy from the environment and to interact with other living organisms and their physical surroundings. The organism should possess the right genes to create offspring and to be able to access enough food and resources. Furthermore, the organism needs to be capable of reproducing itself in a way that is optimally within its environmental niche. These factors, together with gene flow and mutations can cause changes in the proportion of different alleles in the population's gene pool. As time passes, this shift in allele frequency can result in the emergence of new traits and eventually new species. Many of the features that we admire about animals and plants are adaptations, like the lungs or gills that extract oxygen from the air, feathers or fur to provide insulation, long legs for running away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires paying attention to the distinction between the physiological and behavioral traits. Physiological adaptations, such as 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, are not. In addition it is important to understand that lack of planning is not a reason to make something an adaptation. Failure to consider the consequences of a decision even if it seems to be logical, can cause it to be unadaptive.