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What is Free Evolution? Free evolution is the notion that the natural processes that organisms go through can lead them to evolve over time. This includes the evolution of new species and alteration of the appearance of existing ones. Many examples have been given of this, including various varieties of fish called sticklebacks that can live in either fresh or salt water and walking stick insect varieties that are attracted to particular host plants. These mostly reversible traits permutations do not explain the fundamental changes in the body's basic plans. Evolution by Natural Selection Scientists have been fascinated by the development of all living organisms that inhabit our planet for centuries. Charles Darwin's natural selectivity is the most well-known explanation. This happens when individuals who are better-adapted survive and reproduce more 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 and involves the interaction of three factors: variation, reproduction and inheritance. Sexual reproduction and mutation increase the genetic diversity of an animal species. Inheritance refers the transmission of a person’s genetic traits, including recessive and dominant genes to their offspring. Reproduction is the production of viable, fertile offspring, which includes both sexual and asexual methods. Natural selection only occurs when all the factors are in balance. For example, if the dominant allele of the gene allows an organism to live and reproduce more frequently than the recessive allele, the dominant allele will be more prominent within the population. But if the allele confers an unfavorable survival advantage or decreases fertility, it will be eliminated from the population. The process is self-reinforced, which means that an organism with a beneficial characteristic can reproduce and survive longer than an individual with an unadaptive trait. The more offspring an organism produces, the greater its fitness which is measured by its ability to reproduce itself and live. People with desirable traits, like longer necks in giraffes or bright white color patterns in male peacocks, are more likely to survive and have offspring, and thus will eventually make up the majority of the population in the future. Natural selection is a factor in populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution which claims that animals acquire traits by use or inactivity. If a giraffe stretches its neck to reach prey and its neck gets longer, then its offspring will inherit this trait. The difference in neck length between generations will continue until the giraffe's neck gets so long that it can not breed with other giraffes. Evolution through Genetic Drift Genetic drift occurs when alleles of the same gene are randomly distributed in a group. In the end, one will attain fixation (become so widespread that it is unable to be eliminated by natural selection) and other alleles will fall to lower frequencies. This can lead to dominance at the extreme. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small population this could lead to the complete elimination of the recessive gene. This scenario is called the bottleneck effect. It is typical of the evolutionary process that occurs when an enormous number of individuals move to form a population. A phenotypic bottleneck can also occur when survivors of a disaster such as an outbreak or mass hunting event are confined to an area of a limited size. The survivors will be largely homozygous for the dominant allele, which means they will all have the same phenotype, and consequently have the same fitness traits. This could be the result of a war, earthquake or even a disease. The genetically distinct population, if it remains susceptible to genetic drift. Walsh Lewens and Ariew employ Lewens, Walsh and Ariew employ a “purely outcome-oriented” definition of drift as any deviation from the expected values for different fitness levels. They give the famous example of twins who are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, while the other lives to reproduce. This kind of drift could be crucial in the evolution of the species. But, it's not the only way to progress. The main alternative is to use a process known as natural selection, in which the phenotypic variation of the population is maintained through mutation and migration. Stephens claims that there is a huge distinction between treating drift as an actual cause or force, and treating other causes like migration and selection as causes and forces. He claims that a causal-process model of drift allows us to distinguish it from other forces and that this differentiation is crucial. He also claims that drift has a direction, that is it tends to eliminate heterozygosity. He also claims that it also has a magnitude, which is determined by the size of the population. 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 is often known as “Lamarckism” and it asserts that simple organisms evolve into more complex organisms through the inherited characteristics that are a result of the organism's natural actions, use and disuse. Lamarckism is illustrated through a giraffe extending its neck to reach higher branches in the trees. This would cause giraffes to pass on their longer necks to their offspring, who would then get taller. Lamarck the French zoologist, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. In his view living things had evolved from inanimate matter via the gradual progression of events. Lamarck was not the first to suggest that this could be the case, but he is widely seen as being the one who gave the subject its first general and comprehensive treatment. The popular narrative is that Lamarckism became an opponent to Charles Darwin's theory of evolutionary natural selection, and both theories battled it out in the 19th century. Darwinism eventually won, leading to the development of what biologists refer to as the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be acquired through inheritance and instead, it argues that organisms develop through the selective action of environmental factors, including natural selection. While Lamarck believed in the concept of inheritance by acquired characters, and his contemporaries also offered a few words about this idea but it was not an integral part of any of their evolutionary theorizing. This is due in part to the fact that it was never tested scientifically. It's been more than 200 years since the birth of Lamarck, and in the age genomics, there is a growing body of evidence that supports the heritability of acquired traits. This is sometimes referred to as “neo-Lamarckism” or, more commonly, epigenetic inheritance. This is a variant that is as reliable as the popular neodarwinian model. Evolution by adaptation One of the most widespread misconceptions about evolution is that it is driven by a type of struggle for survival. This is a false assumption and ignores other forces driving evolution. The fight for survival can be more effectively described as a struggle to survive in a specific environment, which could involve not only other organisms but also the physical environment. To understand how evolution operates it is important to understand what is adaptation. It is a feature that allows a living organism to live in its environment and reproduce. It can be a physiological structure, like feathers or fur or a behavior, such as moving into shade in hot weather or stepping out at night to avoid the cold. The ability of a living thing to extract energy from its surroundings and interact with other organisms and their physical environment is essential to its survival. The organism must have the right genes to create offspring and to be able to access sufficient food and re sources . Moreover, the organism must be able to reproduce itself in a way that is optimally within its niche. These elements, in conjunction with mutation and gene flow result in a change in the proportion of alleles (different types of a gene) in the population's gene pool. Over time, this change in allele frequencies can result in the emergence of new traits, and eventually new species. Many of the characteristics we find appealing in plants and animals are adaptations. For instance, lungs or gills that draw oxygen from air feathers and fur as insulation long legs to run away from predators, and camouflage to hide. However, a complete understanding of adaptation requires paying attention to the distinction between the physiological and behavioral traits. Physiological adaptations like thick fur or gills, are physical traits, whereas behavioral adaptations, such as the tendency to seek out companions or to move to the shade during hot weather, aren't. In addition it is important to note that lack of planning is not a reason to make something an adaptation. In fact, failure to think about the implications of a choice can render it ineffective despite the fact that it may appear to be reasonable or even essential.