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What is Free Evolution? Free evolution is the idea that the natural processes that organisms go through can lead them to evolve over time. This includes the appearance and development of new species. This has been proven by many examples, including stickleback fish varieties that can be found in salt or fresh water, and walking stick insect varieties that have a preference for particular host plants. These reversible traits are not able to explain fundamental changes to the basic body plan. Evolution through Natural Selection Scientists have been fascinated by the evolution of all the living creatures that live on our planet for centuries. Charles Darwin's natural selection is the most well-known explanation. This is because those who are better adapted survive and reproduce more than those who are less well-adapted. As time passes, a group of well adapted individuals grows and eventually creates a new species. Natural selection is an ongoing 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 enhance the genetic diversity of an animal species. Inheritance is the transfer of a person's genetic traits to their offspring which includes both dominant and recessive alleles. Reproduction is the process of producing viable, fertile offspring. This can be achieved via sexual or asexual methods. All of these elements have to be in equilibrium for natural selection to occur. If, for instance the dominant gene allele causes an organism reproduce and live longer than the recessive gene The dominant allele becomes more prevalent in a group. If the allele confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. The process is self reinforcing which means that an organism with an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive trait. The more offspring an organism produces, the greater its fitness, which is measured by its ability to reproduce itself and live. Individuals with favorable traits, like having a longer neck in giraffes or bright white colors in male peacocks are more likely survive and produce offspring, and thus will become the majority of the population over time. Natural selection is an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which holds that animals acquire traits through the use or absence of use. If a giraffe stretches its neck to reach prey and the neck grows longer, then the children will inherit this characteristic. The difference in neck size between generations will continue to grow until the giraffe becomes unable to breed with other giraffes. Evolution by Genetic Drift Genetic drift occurs when alleles of a gene are randomly distributed in a population. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated by natural selection) and the rest of the alleles will decrease in frequency. This could lead to an allele that is dominant in extreme. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small group this could result in the complete elimination of recessive allele. This scenario is called the bottleneck effect and is typical of an evolutionary process that occurs when an enormous number of individuals move to form a group. 에볼루션 카지노 can also occur when the survivors of a catastrophe like an outbreak or mass hunting incident are concentrated in the same area. The remaining individuals will be largely homozygous for the dominant allele which means that they will all have the same phenotype, and thus have the same fitness characteristics. This could be the result of a war, an earthquake or even a cholera outbreak. Regardless of the cause, the genetically distinct population that remains is susceptible to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a deviation from the expected value due to differences in fitness. They give a famous instance of twins who are genetically identical, share 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 progress. Natural selection is the main alternative, where mutations and migration keep the phenotypic diversity of a population. Stephens asserts that there is a significant distinction between treating drift as an agent or cause and treating other causes such as selection mutation and migration as forces and causes. Stephens claims that a causal process model of drift allows us to differentiate it from other forces, and this distinction is crucial. He also argues that drift has a direction: that is it tends to reduce heterozygosity, and that it also has a size, that is determined by the size of population. Evolution through Lamarckism When students in high school study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution is generally known as “Lamarckism” and it states that simple organisms grow into more complex organisms by the inheritance of characteristics that result from the natural activities of an organism usage, use and disuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher leaves in the trees. This could cause the longer necks of giraffes to be passed to their offspring, who would then grow even taller. Lamarck was a French zoologist and, in his opening lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on 17 May 1802, he presented an innovative concept that completely challenged previous thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate materials through a series of gradual steps. Lamarck was not the first to suggest that this could be the case but the general consensus is that he was the one giving the subject its first general and thorough treatment. The prevailing story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection and that the two theories fought each other in the 19th century. Darwinism ultimately prevailed which led to what biologists call the Modern Synthesis. This theory denies that traits acquired through evolution can be inherited, and instead suggests that organisms evolve through the action of environmental factors, including natural selection. Although Lamarck supported the notion of inheritance by acquired characters and his contemporaries offered a few words about this idea but it was not a central element in any of their evolutionary theorizing. This is largely due to the fact that 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 often called “neo-Lamarckism” or, more frequently, epigenetic inheritance. This is a version that is as reliable as the popular Neodarwinian model. Evolution through adaptation One of the most common misconceptions about evolution is that it is driven by a sort of struggle to survive. This view is inaccurate and overlooks other forces that drive evolution. The fight for survival can be more effectively described as a struggle to survive within a specific environment, which may include not just other organisms but as well the physical environment. To understand how evolution works it is beneficial to consider what adaptation is. Adaptation refers to any particular feature that allows an organism to survive and reproduce in its environment. It could be a physical structure, like fur or feathers. Or it can be a behavior trait that allows you to move into the shade during hot weather, or escaping the cold at night. The capacity of an organism to extract energy from its environment and interact with other organisms as well as their physical environment is essential to its survival. The organism must possess the right genes to create offspring, and must be able to access sufficient food and other resources. Moreover, the organism must be capable of reproducing itself at an optimal rate within its environmental niche. These elements, along with mutations and gene flow can result in changes in the proportion of different alleles in a population’s gene pool. As time passes, this shift in allele frequencies could result in the emergence of new traits and eventually new species. A lot of the traits we appreciate in plants and animals are adaptations. For example lung or gills that extract oxygen from the air, fur and feathers as insulation, long legs to run away from predators, and camouflage to hide. To comprehend adaptation it is essential to differentiate between physiological and behavioral traits. Physical characteristics like the thick fur and gills are physical traits. Behavioral adaptations are not an exception, for instance, the tendency of animals to seek out companionship or retreat into shade during hot temperatures. Furthermore, it is important to note that lack of planning does not make something an adaptation. In fact, failure to consider the consequences of a decision can render it unadaptive, despite the fact that it may appear to be reasonable or even essential.