quartcourt73

What is Free Evolution? Free evolution is the idea that natural processes can cause organisms to evolve over time. This includes the creation of new species and transformation of the appearance of existing species. Many examples have been given of this, including different varieties of fish called sticklebacks that can live in salt or fresh water, as well as walking stick insect varieties that favor specific host plants. These reversible traits however, are not able to explain fundamental changes in basic body plans. Evolution by Natural Selection The development of the myriad living creatures on Earth is a mystery that has intrigued scientists for decades. Charles Darwin's natural selection theory is the best-established explanation. This happens when individuals who are better-adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, the population of well-adapted individuals becomes larger and eventually develops into an entirely new species. Natural selection is an ongoing process that involves the interaction of three elements that are inheritance, variation and reproduction. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity of an animal species. Inheritance refers the transmission of a person's genetic traits, including both dominant and recessive genes, to their offspring. Reproduction is the process of producing viable, fertile offspring, which includes both sexual and asexual methods. Natural selection only occurs when all of these factors are in equilibrium. If, for example an allele of a dominant gene causes an organism reproduce and survive more than the recessive allele, then the dominant allele will become more prevalent in a population. But if the allele confers a disadvantage in survival or decreases fertility, it will be eliminated from the population. This process is self-reinforcing meaning that an organism that has a beneficial trait will survive and reproduce more than one with a maladaptive trait. The greater an organism's fitness as measured by its capacity to reproduce and survive, is the greater number of offspring it can produce. Individuals with favorable traits, such as longer necks in giraffes and bright white colors in male peacocks are more likely survive and have offspring, which means they will become the majority of the population in the future. Natural selection is only a factor in populations and not on individuals. This is a major distinction from the Lamarckian evolution theory which holds that animals acquire traits through use or lack of use. For instance, if a giraffe's neck gets longer through stretching to reach for prey its offspring will inherit a more long neck. The difference in neck length between generations will continue until the giraffe's neck becomes too long to no longer breed with other giraffes. Evolution by Genetic Drift Genetic drift occurs when alleles from one gene are distributed randomly within a population. Eventually, one of them will reach fixation (become so common that it can no longer be removed through natural selection), while other alleles fall to lower frequency. This can lead to a dominant allele in extreme. The other alleles are virtually eliminated and heterozygosity been reduced to zero. In 바카라 에볼루션 of people this could result in the total elimination of recessive alleles. This is known as the bottleneck effect. It is typical of the evolution process that occurs when a large number individuals migrate to form a population. A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or a mass hunting incident are concentrated in an area of a limited size. The survivors will have an dominant allele, and will have the same phenotype. This could be caused by earthquakes, war or even a plague. Whatever the reason the genetically distinct group that is left might be susceptible to genetic drift. Walsh Lewens, Walsh and Ariew define drift as a deviation from expected values due to differences in fitness. They provide the famous case of twins that are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, but the other lives to reproduce. This kind of drift can play a significant part in the evolution of an organism. It's not the only method for evolution. The primary alternative is a process known as natural selection, where the phenotypic diversity of a population is maintained by mutation and migration. Stephens asserts that there is a major distinction between treating drift as a force or an underlying cause, and considering other causes of evolution, such as selection, mutation, and migration as forces or causes. He argues that a causal-process model of drift allows us to distinguish it from other forces and this differentiation is crucial. He further argues that drift has a direction: that is it tends to reduce heterozygosity, and that it also has a size, which is determined by population size. Evolution by Lamarckism Biology students in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is often referred to as “Lamarckism” and it states that simple organisms develop into more complex organisms by the inheritance of characteristics that result from the organism's natural actions usage, use and disuse. Lamarckism can be illustrated by an giraffe's neck stretching to reach higher leaves in the trees. This could result in giraffes passing on their longer necks to offspring, who then become taller. Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced an innovative concept that completely challenged previous thinking about organic transformation. According to Lamarck, living things evolved from inanimate material through a series of gradual steps. Lamarck wasn't the first to propose this, but he was widely thought of as the first to offer the subject a thorough and general treatment. The predominant story is that Charles Darwin's theory on natural selection and Lamarckism were competing in the 19th century. Darwinism ultimately prevailed which led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down and instead argues organisms evolve by the selective action of environment elements, like Natural Selection. While Lamarck endorsed the idea 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 due to the fact that it was never scientifically tested. It's been over 200 year since Lamarck's birth and in the field of age genomics, there is a growing body of evidence that supports the heritability acquired characteristics. It is sometimes called “neo-Lamarckism” or more commonly, epigenetic inheritance. It is a form of evolution that is as valid as the more well-known Neo-Darwinian theory. Evolution through the process of adaptation One of the most popular misconceptions about evolution is that it is driven by a sort of struggle for survival. This notion is not true and ignores other forces driving evolution. The struggle for survival is more effectively described as a struggle to survive in a specific environment, which can be a struggle that involves not only other organisms but as well the physical environment. To understand how evolution operates, it is helpful to consider what adaptation is. It refers to a specific feature that allows an organism to live and reproduce in its environment. It could be a physical structure like feathers or fur. Or it can be a characteristic of behavior that allows you to move towards shade during hot weather or moving 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 environment, is crucial to its survival. The organism should possess the right genes to produce offspring, and be able to find enough food and resources. Moreover, the organism must be able to reproduce itself at an optimal rate within its niche. These elements, in conjunction with gene flow and mutation result in an alteration in the percentage of alleles (different forms of a gene) in the population's gene pool. The change in frequency of alleles can lead to the emergence of new traits, and eventually new species as time passes. Many of the characteristics we admire in plants and animals are adaptations. For instance lung or gills that extract oxygen from the air feathers and fur for insulation and long legs to get away from predators and camouflage for hiding. To understand the concept of adaptation, it is important to discern between physiological and behavioral characteristics. Physiological adaptations, like thick fur or gills, are physical characteristics, whereas behavioral adaptations, like the tendency to search for friends or to move to the shade during hot weather, aren't. It is important to remember that a the absence of planning doesn't make an adaptation. A failure to consider the consequences of a decision even if it seems to be rational, may make it unadaptive.