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What is Free Evolution? Free evolution is the concept that natural processes can cause organisms to develop over time. This includes the development of new species and the change in appearance of existing species. This is evident in numerous examples of stickleback fish species that can live in salt or fresh water, and walking stick insect varieties that have a preference for particular host plants. These reversible traits cannot 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 inhabit our planet for centuries. The most widely accepted explanation is that of Charles Darwin's natural selection process, an evolutionary process that occurs when individuals that are better adapted survive and reproduce more effectively than those who are less well-adapted. Over time, a community of well-adapted individuals expands and eventually forms a whole new species. Natural selection is an ongoing process that involves the interaction of three elements including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity within a species. Inheritance is the term used to describe the transmission of a person's genetic traits, including recessive and dominant genes, to their offspring. 바카라 에볼루션 is the process of generating viable, fertile offspring. This can be achieved via sexual or asexual methods. Natural selection is only possible when all of these factors are in equilibrium. If, for instance an allele of a dominant gene causes an organism reproduce and live longer than the recessive gene, then the dominant allele becomes more prevalent in a population. If the allele confers a negative advantage to survival or reduces the fertility of the population, it will be eliminated. The process is self-reinforcing, meaning that a species with a beneficial characteristic will survive and reproduce more than one with an unadaptive characteristic. The more fit an organism is as measured by its capacity to reproduce and endure, is the higher number of offspring it can produce. Individuals with favorable characteristics, such as a long neck in giraffes, or bright white patterns on male peacocks are more likely than others to survive and reproduce which eventually leads to them becoming the majority. Natural selection only acts on populations, not on individuals. This is a significant distinction from the Lamarckian evolution theory, which states that animals acquire traits due to use or lack of use. For example, if a animal's neck is lengthened by stretching to reach prey, its offspring will inherit a longer neck. The differences in neck length between generations will continue until the giraffe's neck becomes too long to not breed with other giraffes. Evolution by Genetic Drift In genetic drift, the alleles within a gene can attain different frequencies in a group due to random events. 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 diminish in frequency. This can result in a dominant allele in extreme. The other alleles are eliminated, and heterozygosity falls to zero. In a small population it could result in the complete elimination of the recessive gene. This scenario is known as a bottleneck effect and it is typical of evolutionary process that occurs when a large amount of individuals migrate to form a new group. A phenotypic bottleneck can also occur when survivors of a catastrophe, such as an epidemic or a mass hunting event, are concentrated within a narrow area. The survivors will have a dominant allele and thus will have the same phenotype. This situation could be caused by earthquakes, war or even a plague. The genetically distinct population, if left susceptible to genetic drift. Walsh Lewens, Lewens, and Ariew utilize Lewens, Walsh, and Ariew use a “purely outcome-oriented” definition of drift as any departure from the expected values of variations in fitness. They cite a famous instance of twins who are genetically identical, share identical phenotypes, but one is struck by lightning and dies, while the other lives and reproduces. This kind of drift can play a significant part in the evolution of an organism. However, it is not the only method to develop. The most common alternative is to use a process known as natural selection, in which the phenotypic diversity of a population is maintained by mutation and migration. Stephens asserts that there is a significant difference between treating the phenomenon of drift as an agent or cause and treating other causes such as selection mutation and migration as forces and causes. He argues that a causal-process model of drift allows us to separate it from other forces and this distinction is essential. He also argues that drift is both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by population size. Evolution through Lamarckism When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, also referred to as “Lamarckism”, states that simple organisms transform into more complex organisms adopting traits that result from the use and abuse of an organism. Lamarckism is typically illustrated by an image of a giraffe that extends its neck to reach leaves higher up in the trees. This causes the longer necks of giraffes to be passed on to their offspring who would then become taller. Lamarck, a French Zoologist, introduced an idea that was revolutionary in his opening lecture at the Museum of Natural History of Paris. He challenged the conventional wisdom on organic transformation. According to Lamarck, living creatures evolved from inanimate matter by a series of gradual steps. Lamarck wasn't the first to suggest this, but he was widely considered to be the first to give the subject a thorough and general explanation. The predominant story is that Charles Darwin's theory of natural selection and Lamarckism fought in the 19th century. Darwinism ultimately won, leading to what biologists call the Modern Synthesis. This theory denies the possibility that acquired traits can be inherited and instead suggests that organisms evolve through the action of environmental factors, like natural selection. Lamarck and his contemporaries supported the idea that acquired characters could be passed on to the next generation. However, this notion was never a central part of any of their theories on evolution. This is partly due to the fact that it was never validated scientifically. However, it has been more than 200 years since Lamarck was born and, in the age of genomics there is a vast amount of evidence to support the possibility of inheritance of acquired traits. This is also known as “neo Lamarckism”, or more generally epigenetic inheritance. It is a version of evolution that is just 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 for survival. In fact, this view is a misrepresentation of natural selection and ignores the other forces that are driving evolution. The fight for survival can be better described as a fight to survive in a particular environment. This may include not only other organisms but also the physical environment itself. Understanding the concept of adaptation is crucial to comprehend evolution. It is a feature that allows a living organism to live in its environment and reproduce. It can be a physical structure, such as feathers or fur. Or it can be a behavior trait, like moving to the shade during hot weather or coming out to avoid the cold at night. The survival of an organism depends on its ability to extract energy from the environment and interact with other organisms and their physical environments. The organism must have the right genes to create offspring and be able find sufficient food and resources. In addition, the organism should be capable of reproducing itself at a high rate within its niche. These elements, along with gene flow and mutations can result in changes in the proportion of different alleles in the population's gene pool. Over time, this change in allele frequencies could result in the development of new traits and ultimately new species. A lot of the traits we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, fur or feathers to protect themselves long legs to run away from predators and camouflage to hide. However, a thorough understanding of adaptation requires attention to the distinction between physiological and behavioral characteristics. Physiological adaptations like thick fur or gills, are physical traits, while behavioral adaptations, like the tendency to seek out companions or to move to the shade during hot weather, are not. It is also important to keep in mind that the absence of planning doesn't cause an adaptation. In fact, a failure to consider the consequences of a choice can render it unadaptive even though it might appear logical or even necessary.