openoil59

What is Free Evolution? Free evolution is the concept that the natural processes that organisms go through can lead to their development over time. This includes the creation of new species and alteration of the appearance of existing ones. A variety of examples have been provided of this, such as different varieties of fish called sticklebacks that can live in fresh or salt water and walking stick insect varieties that are attracted to particular host plants. These typically reversible traits cannot explain fundamental changes to the basic body plan. Evolution by Natural Selection The development of the myriad of living organisms on Earth is a mystery that has intrigued scientists for decades. The most well-known explanation is Darwin's natural selection, which occurs when individuals that are better adapted survive and reproduce more effectively than those less well-adapted. As time passes, a group 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 enhance the genetic diversity within an animal species. Inheritance refers the transmission of a person's genetic traits, which include recessive and dominant genes to their offspring. Reproduction is the process of producing viable, fertile offspring. This can be accomplished through sexual or asexual methods. All of these elements must be in balance for natural selection to occur. If, for instance an allele of a dominant gene allows an organism to reproduce and survive more than the recessive gene, then the dominant allele will become more prevalent in a group. If the allele confers a negative survival advantage or lowers the fertility of the population, it will be eliminated. The process is self reinforcing which means that the organism with an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive feature. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the more offspring it will produce. Individuals with favorable traits, like a long neck in Giraffes, or the bright white patterns on male peacocks are more likely to others to live and reproduce which eventually leads to them becoming the majority. Natural selection is a factor in populations and not on individuals. evolutionkr.kr 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 extends its neck to catch prey and its neck gets longer, then the children will inherit this characteristic. The difference in neck size between generations will continue to grow until the giraffe is unable to breed with other giraffes. Evolution by Genetic Drift In genetic drift, the alleles within a gene can attain different frequencies within a population through random events. In the end, only one will be fixed (become common enough to no longer be eliminated by natural selection) and the rest of the alleles will diminish in frequency. In extreme cases it can lead to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small population it could result in the complete elimination of recessive gene. This scenario is called the bottleneck effect and is typical of an evolution process that occurs when the number of individuals migrate to form a group. A phenotypic bottleneck may also occur when the survivors of a disaster like an outbreak or mass hunting event are confined to the same area. The surviving individuals will be largely homozygous for the dominant allele which means that they will all share the same phenotype and thus have the same fitness characteristics. This may be the result of a war, an earthquake, or even a plague. Whatever the reason, the genetically distinct population that remains is 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 differences in fitness. They give a famous example of twins that are genetically identical and have identical phenotypes, and yet one is struck by lightening and dies while the other lives and reproduces. This type of drift is very important in the evolution of the species. It is not the only method for evolution. The primary alternative is to use a process known as natural selection, in which the phenotypic diversity of the population is maintained through mutation and migration. Stephens asserts that there is a big difference between treating the phenomenon of drift as a force, or an underlying cause, and treating other causes of evolution like selection, mutation and migration as forces or causes. Stephens claims that a causal process explanation of drift lets us differentiate it from other forces and that this distinction is essential. He also claims that drift has a direction, that is it tends to eliminate heterozygosity, and that 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”, states that simple organisms develop into more complex organisms inheriting characteristics that are a product of an organism's use and disuse. Lamarckism is usually illustrated with a picture of a giraffe extending its neck further to reach higher up in the trees. This would cause the longer necks of giraffes to be passed on to their offspring who would grow taller. Lamarck the French zoologist, presented an idea that was revolutionary in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. In his opinion living things had evolved from inanimate matter through an escalating series of steps. Lamarck wasn't the first to propose this however he was widely regarded as the first to give the subject a thorough and general explanation. The prevailing story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolutionary natural selection and both theories battled out in the 19th century. Darwinism ultimately won and led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down through generations and instead, it claims that organisms evolve through the influence of environment factors, including Natural Selection. Lamarck and his contemporaries supported the notion that acquired characters could be passed on to future generations. However, this notion was never a major part of any of their theories on evolution. This is due to the fact that it was never scientifically tested. 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 of acquired traits. This is also referred to as “neo Lamarckism”, or more generally epigenetic inheritance. This is a version that is as reliable as the popular neodarwinian model. Evolution through adaptation One of the most commonly-held 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 functions it is important to think about what adaptation is. Adaptation refers to any particular feature that allows an organism to survive and reproduce within its environment. It can be a physical feature, such as feathers or fur. Or it can be a behavior trait that allows you to move into the shade during the heat, or coming out to avoid the cold at night. The ability of an organism to extract energy from its surroundings and interact with other organisms as well as their physical environments is essential to its survival. The organism must possess the right genes to create offspring, and it must be able to find sufficient food and other resources. The organism must also be able reproduce itself at a rate that is optimal for its niche. These elements, in conjunction with mutation and gene flow, lead to changes in the ratio of alleles (different types of a gene) in a population's gene pool. This shift in the frequency of alleles could lead to the development of new traits and eventually new species over time. A lot of the traits we find appealing in plants and animals are adaptations. For example, lungs or gills that extract oxygen from air feathers and fur for insulation long legs to run away from predators, and camouflage to hide. To comprehend adaptation, it is important to discern between physiological and behavioral characteristics. Physiological adaptations like the thick fur or gills are physical traits, while behavioral adaptations, like the tendency to search for companions or to retreat into the shade in hot weather, are not. It is important to keep in mind that insufficient planning does not cause an adaptation. Failure to consider the consequences of a decision, even if it appears to be rational, could cause it to be unadaptive.