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What is Free Evolution? Free evolution is the notion that the natural processes of organisms can lead them to evolve over time. This includes the appearance and development of new species. A variety of examples have been provided of this, including various varieties of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that are attracted to particular host plants. These reversible traits, however, cannot explain fundamental changes in basic body plans. Evolution by Natural Selection The development of the myriad of living organisms on Earth is a mystery that has intrigued scientists for decades. The best-established explanation is Darwin's natural selection, a process that occurs when better-adapted individuals survive and reproduce more successfully than those less well adapted. As time passes, the number of individuals who are well-adapted grows and eventually creates a new species. Natural selection is a process that is cyclical and involves the interaction of three factors that are: reproduction, variation and inheritance. Mutation and sexual reproduction increase the genetic diversity of a species. Inheritance refers to the transmission of genetic characteristics, which includes recessive and dominant genes, to their offspring. Reproduction is the production of fertile, viable offspring which includes both sexual and asexual methods. Natural selection can only occur when all these elements are in equilibrium. For example the case where an allele that is dominant at a gene can cause an organism to live and reproduce more often than the recessive allele, the dominant allele will become more prevalent within the population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will disappear. The process is self reinforcing, which means that an organism that has an adaptive trait will survive and reproduce far more effectively than those with a maladaptive feature. The more offspring an organism produces the more fit it is which is measured by its ability to reproduce itself and survive. People with desirable traits, like having a longer neck in giraffes or bright white patterns of color in male peacocks are more likely be able to survive and create offspring, so they will make up the majority of the population in the future. Natural selection only affects populations, not on individual organisms. This is a crucial distinction from the Lamarckian theory of evolution which holds that animals acquire traits through use or lack of use. If a giraffe extends its neck in order to catch prey and the neck grows longer, then the offspring will inherit this trait. The difference in neck size between generations will continue to increase until the giraffe becomes unable to reproduce with other giraffes. Evolution through Genetic Drift In the process of genetic drift, alleles of a gene could be at different frequencies in a population 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 rest of the alleles will diminish in frequency. In extreme cases, this leads to one allele dominance. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small population, this could result in the complete elimination of the recessive gene. This is known as a bottleneck effect and it is typical of the kind of evolutionary process when a large amount of individuals move to form a new group. A phenotypic bottleneck may also occur when survivors of a disaster like an outbreak or mass hunt incident are concentrated in the same area. The remaining individuals will be mostly homozygous for the dominant allele which means they will all share the same phenotype and therefore have the same fitness traits. This could be the result of a conflict, earthquake, or even a plague. Regardless of the cause the genetically distinct population that is left might be prone 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 and have identical phenotypes and yet one is struck by lightning and dies, whereas the other lives and reproduces. This type of drift is crucial in the evolution of an entire species. However, it is not the only way to progress. The primary alternative is to use a process known as natural selection, where phenotypic variation in an individual is maintained through mutation and migration. Stephens argues there is a huge distinction between treating drift as a force or cause, and treating other causes like migration and selection as causes and forces. He claims that a causal-process model of drift allows us to differentiate it from other forces and that this distinction is essential. He argues further that drift has an orientation, i.e., it tends to eliminate heterozygosity. It also has a size which is determined based on the size of the population. Evolution by Lamarckism In high school, students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, commonly referred to as “Lamarckism” is based on the idea that simple organisms evolve into more complex organisms by inheriting characteristics that are a product of an organism's use and disuse. Lamarckism is typically illustrated by a picture of a giraffe stretching its neck longer to reach leaves higher up in the trees. This process would cause giraffes to pass on their longer necks to offspring, who would then become taller. Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th May 1802, he presented a groundbreaking concept that radically challenged the previous understanding of organic transformation. According to him living things evolved from inanimate matter via a series of gradual steps. Lamarck wasn't the only one to make this claim however he was widely thought of as the first to provide the subject a thorough and general explanation. The most popular story is that Lamarckism grew into a rival to Charles Darwin's theory of evolution by natural selection and that the two theories battled it out in the 19th century. Darwinism eventually prevailed and led to the development of what biologists refer to as the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be inherited and instead argues that organisms evolve through the selective action of environmental factors, like natural selection. While Lamarck supported the notion of inheritance by acquired characters and his contemporaries also offered a few words about this idea but it was not a major feature in any of their evolutionary theories. This is largely due to the fact that it was never tested scientifically. It's been over 200 year since Lamarck's birth and in the field of age genomics there is a growing evidence base that supports the heritability-acquired characteristics. This is also referred to as “neo Lamarckism”, or more generally epigenetic inheritance. It is a version of evolution that is as relevant 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 무료에볼루션 , this view is inaccurate and overlooks the other forces that are driving evolution. The fight for survival can be more effectively described as a struggle to survive within a particular environment, which can involve not only other organisms, but also the physical environment. Understanding the concept of adaptation is crucial to understand evolution. The term “adaptation” refers to any characteristic that allows a living organism to live in its environment and reproduce. It could be a physical structure, like feathers or fur. 에볼루션사이트 could also 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 a living thing to extract energy from its surroundings and interact with other organisms as well as their physical environment is essential to its survival. The organism must have the right genes to produce offspring, and be able to find enough food and resources. Moreover, the organism must be able to reproduce itself in a way that is optimally within its environmental niche. These factors, in conjunction 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 frequencies could lead to the emergence of new traits and ultimately new species. Many of the features that we admire about animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, feathers or fur to protect themselves, long legs for running away from predators and camouflage for hiding. However, a proper understanding of adaptation requires a keen eye to the distinction between behavioral and physiological traits. Physical characteristics like large gills and thick fur are physical traits. Behavior adaptations aren't, such as the tendency of animals to seek out companionship or move into the shade in hot weather. It is important to remember that a insufficient planning does not make an adaptation. Failure to consider the implications of a choice even if it seems to be logical, can cause it to be unadaptive.