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What is Free Evolution? Free evolution is the notion that the natural processes of living organisms can lead to their development over time. This includes the creation of new species as well as the transformation of the appearance of existing species. This has been proven by many examples of stickleback fish species that can live in fresh or saltwater and walking stick insect species that prefer specific host plants. These reversible traits however, are not able to be the reason for fundamental changes in body plans. Evolution by Natural Selection Scientists have been fascinated by the evolution of all the living creatures that live on our planet for ages. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when people who are more well-adapted survive and reproduce more than those who are less well-adapted. Over time, a community 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 factors that are inheritance, variation and reproduction. Mutation and sexual reproduction increase genetic diversity in an animal species. Inheritance refers to the transmission of a person’s genetic traits, including recessive and dominant genes, to their offspring. Reproduction is the production of fertile, viable offspring which includes both asexual and sexual methods. Natural selection can only occur when all these elements are in balance. For example, if the dominant allele of the gene can cause an organism to live and reproduce more often than the recessive allele, the dominant allele will be more prevalent within the population. 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 trait will live and reproduce much more than those with a maladaptive trait. The more fit an organism is, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with desirable characteristics, such as a long neck in giraffes, or bright white patterns on male peacocks are more likely than others to survive and reproduce, which will eventually lead to them becoming the majority. Natural selection only affects populations, not individual organisms. This is a significant distinction from the Lamarckian evolution theory, which states that animals acquire traits either through the use or absence of use. If a giraffe stretches its neck in order to catch prey, and the neck becomes longer, then the offspring will inherit this characteristic. The difference in neck size between generations will continue to increase until the giraffe is unable to reproduce with other giraffes. Evolution by Genetic Drift Genetic drift occurs when the alleles of the same gene are randomly distributed within a population. At some point, one will reach fixation (become so common that it is unable to be eliminated through natural selection) and the other alleles drop to lower frequencies. In the extreme, this leads to a single allele dominance. page are eliminated, and heterozygosity decreases to zero. In a small group it could lead to the total elimination of recessive allele. This is known as the bottleneck effect. It is typical of an evolutionary process that occurs when the number of individuals migrate to form a group. A phenotypic bottleneck may occur when survivors of a disaster like an epidemic or a massive hunt, are confined into a small area. The survivors will carry an dominant allele, and will share the same phenotype. This could be the result of a war, earthquake or even a cholera outbreak. The genetically distinct population, if left vulnerable to genetic drift. Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They give a famous instance of twins who are genetically identical and have identical phenotypes, but one is struck by lightening and dies while the other lives and reproduces. This kind of drift can be crucial in the evolution of an entire species. It is not the only method for evolution. The primary alternative is a process known as natural selection, in which the phenotypic variation of an individual is maintained through mutation and migration. Stephens claims that there is a significant difference between treating 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 model of drift allows us to separate it from other forces and that this distinction is crucial. He further argues that drift has a direction: that is, it tends to eliminate heterozygosity. He also claims that it also has a magnitude, that is determined by population size. Evolution through Lamarckism Biology students in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is commonly called “Lamarckism” and it states that simple organisms develop into more complex organisms via the inherited characteristics which result from an organism's natural activities usage, use and disuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher branches in the trees. This could result in giraffes passing on their longer necks to offspring, who then grow even taller. Lamarck the French zoologist, presented an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. In his opinion living things had evolved from inanimate matter via an escalating series of steps. Lamarck wasn't the only one to propose this however he was widely thought of as the first to provide the subject a thorough and general explanation. The predominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism fought in the 19th century. Darwinism eventually prevailed and led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down and instead, it claims that organisms evolve through the selective influence of environmental factors, such as Natural Selection. Lamarck and his contemporaries endorsed the idea that acquired characters could be passed on to the next generation. However, this notion was never a major part of any of their theories on evolution. This is partly due to the fact that it was never validated scientifically. But it is now more than 200 years since Lamarck was born and, in the age of genomics there is a huge body of evidence supporting the possibility of inheritance of acquired traits. It is sometimes referred to as “neo-Lamarckism” or more commonly, epigenetic inheritance. It is a form of evolution that is just as relevant as the more popular neo-Darwinian model. Evolution by the process of adaptation One of the most common misconceptions about evolution is being driven by a struggle to survive. This is a false assumption and ignores other forces driving evolution. The fight for survival is more accurately described as a struggle to survive in a certain environment. This may be a challenge for not just other living things but also the physical environment. To understand how evolution functions it is important to think about what adaptation is. It is a feature that allows living organisms to live in its environment and reproduce. It can be a physiological feature, such as fur or feathers, or a behavioral trait, such as moving into shade in hot weather or coming out at night to avoid the cold. The capacity of an organism to extract energy from its surroundings and interact with other organisms and their physical environment, is crucial to its survival. The organism should possess the right genes for producing offspring, and be able to find sufficient food and resources. Moreover, the organism must be capable of reproducing in a way that is optimally within its environmental niche. These factors, in conjunction with mutations and gene flow, can lead to a shift in the proportion of different alleles in a population’s gene pool. As time passes, this shift in allele frequencies can result in the emergence of new traits, and eventually new species. Many of the characteristics we find appealing in animals and plants are adaptations. For example lung 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 proper understanding of adaptation requires paying attention to the distinction between the physiological and behavioral traits. Physiological adaptations, like the thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the tendency to seek out companions or to retreat into the shade in hot weather, are not. It is also important to keep in mind that lack of planning does not result in an adaptation. In fact, failing to consider the consequences of a behavior can make it ineffective, despite the fact that it appears to be sensible or even necessary.