washerweasel10

What is Free Evolution? Free evolution is the notion that the natural processes of organisms can cause them to develop over time. This includes the appearance and development of new species. A variety of examples have been provided of this, such as different kinds of stickleback fish that can live in either salt or fresh water, and walking stick insect varieties that favor particular host plants. These are mostly reversible traits, however, cannot explain fundamental changes in body plans. Evolution by Natural Selection The evolution of the myriad living organisms on Earth is a mystery that has intrigued scientists for centuries. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when those who are better adapted have more success in reproduction and survival 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 an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity of a species. Inheritance refers the transmission of genetic traits, including both dominant and recessive genes and their offspring. Reproduction is the process of generating viable, fertile offspring. This can be achieved by both asexual or sexual methods. Natural selection only occurs when all of these factors are in harmony. If, for instance, a dominant gene allele allows an organism to reproduce and last longer than the recessive gene allele then the dominant allele is more common in a population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will disappear. The process is self-reinforced, which means that an organism that has a beneficial trait will survive and reproduce more than one with a maladaptive characteristic. The more fit an organism is as measured by its capacity to reproduce and endure, is the higher number of offspring it produces. People with good characteristics, like having a longer neck in giraffes or bright white color patterns in male peacocks are more likely to survive and produce offspring, which means they will become the majority of the population over time. Natural selection is an aspect of populations and not on individuals. This is an important distinction from the Lamarckian theory of evolution which argues that animals acquire traits through use or disuse. If a giraffe stretches its neck to reach prey, and the neck becomes longer, then its offspring will inherit this trait. The difference in neck size between generations will continue to grow until the giraffe is no longer able to reproduce with other giraffes. Evolution through Genetic Drift In genetic drift, the alleles at a gene may attain different frequencies within a population due to random events. In the end, one will attain fixation (become so common that it cannot be eliminated through natural selection) and other alleles fall to lower frequencies. In the extreme, this leads to one allele dominance. The other alleles have been 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 called a bottleneck effect, and it is typical of evolutionary process that occurs when a large amount of individuals move to form a new population. A phenotypic bottleneck may also occur when the survivors of a disaster like an outbreak or a mass hunting incident are concentrated in an area of a limited size. The remaining individuals are likely to be homozygous for the dominant allele, which means that they will all have the same phenotype and will consequently share the same fitness characteristics. This situation could be caused by war, earthquakes or even plagues. The genetically distinct population, if it remains vulnerable to genetic drift. Walsh Lewens, Lewens, and Ariew use Lewens, Walsh and Ariew employ a “purely outcome-oriented” definition of drift as any departure from expected values for different fitness levels. They give the famous example of twins that are genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, whereas the other is able to reproduce. This kind of drift can be vital to the evolution of the species. However, it's not the only method to evolve. Natural selection is the primary alternative, in which mutations and migration keep the phenotypic diversity of the population. Stephens asserts that there is a significant difference between treating the phenomenon of drift as a force or cause, and treating other causes such as selection mutation and migration as forces and causes. Stephens claims that a causal process explanation of drift lets us differentiate it from other forces and this differentiation is crucial. He also claims that drift is a directional force: that is it tends to reduce heterozygosity. It also has a magnitude, that is determined by the size of the population. Evolution through Lamarckism In high school, students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, commonly referred to as “Lamarckism which means that simple organisms develop into more complex organisms by taking on traits that are a product of the organism's use and misuse. Lamarckism can be demonstrated by the giraffe's neck being extended to reach higher branches in the trees. This causes giraffes' longer necks to be passed on to their offspring who would grow 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 a groundbreaking concept that radically challenged the conventional wisdom about organic transformation. In his opinion living things evolved from inanimate matter via the gradual progression of events. Lamarck wasn't the first to suggest this however he was widely considered to be the first to give the subject a comprehensive and general explanation. The most popular story is that Lamarckism became a rival to Charles Darwin's theory of evolutionary natural selection, and that the two theories fought it out in the 19th century. Darwinism eventually prevailed and led to the development of what biologists today refer to as the Modern Synthesis. The Modern Synthesis 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. While 에볼루션 룰렛 endorsed the idea of inheritance through acquired characters and his contemporaries paid lip-service to this notion but it was not a central element in any of their evolutionary theorizing. This is partly because it was never tested scientifically. It's been over 200 years since the birth of Lamarck and in the field of age genomics, there is a growing evidence-based body of evidence to support the heritability-acquired characteristics. This is sometimes called “neo-Lamarckism” or, more frequently, epigenetic inheritance. It is a form of evolution that is just as valid as the more popular Neo-Darwinian model. Evolution by Adaptation One of the most popular misconceptions about evolution is that it is being driven by a struggle for survival. This view is inaccurate and ignores other forces driving evolution. The struggle for survival is more accurately described as a struggle to survive within a particular environment, which can be a struggle that involves not only other organisms, but also the physical environment. To understand how evolution operates, it is helpful to understand what is adaptation. Adaptation refers to any particular feature that allows an organism to live and reproduce within its environment. It could be a physiological structure, such as fur or feathers or a behavioral characteristic like moving to the shade during hot weather or stepping out at night to avoid the cold. An organism's survival depends on its ability to draw energy from the environment and to interact with other living organisms and their physical surroundings. The organism must have the right genes to produce offspring, and must be able to access enough food and other resources. Moreover, the organism must be capable of reproducing itself in a way that is optimally within its environment. These factors, together with gene flow and mutation result in an alteration in the percentage of alleles (different forms of a gene) in the gene pool of a population. Over time, this change 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, such as lungs or gills to extract oxygen from the air, feathers or fur to provide insulation long legs to run away from predators and camouflage to hide. However, a proper understanding of adaptation requires attention to the distinction between physiological and behavioral characteristics. Physiological adaptations like thick fur or gills are physical traits, whereas behavioral adaptations, like the desire to find companions or to move to shade in hot weather, aren't. It is also important to keep in mind that insufficient planning does not cause an adaptation. Inability to think about the implications of a choice even if it appears to be logical, can make it inflexible.