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What is Free Evolution? Free evolution is the notion that natural processes can cause organisms to develop over time. This includes the creation of new species as well as the change in appearance of existing ones. Many examples have been given of this, including different kinds of stickleback fish that can live in salt or fresh water, as well as walking stick insect varieties 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 development of all living organisms that inhabit our planet for centuries. The most well-known explanation is Darwin's natural selection process, an evolutionary process that occurs when better-adapted individuals survive and reproduce more successfully than those less well adapted. Over time, a population of well-adapted individuals increases and eventually becomes a new species. Natural selection is an ongoing process that is characterized by the interaction of three elements that are inheritance, variation and reproduction. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within an animal species. Inheritance is the transfer of a person's genetic traits to their offspring, which includes both recessive and dominant alleles. Reproduction is the process of producing fertile, viable offspring which includes both asexual and sexual methods. All of these factors have to be in equilibrium to allow natural selection to take place. For example when an allele that is dominant at the gene allows an organism to live and reproduce more frequently than the recessive allele, the dominant allele will become more prominent in the population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will go away. The process is self-reinforced, which means that an organism with a beneficial characteristic will survive and reproduce more than one with an inadaptive trait. The greater an organism's fitness, measured by its ability reproduce and survive, is the more offspring it will produce. People with good characteristics, such as having a long neck in giraffes, or bright white color patterns on male peacocks are more likely than others to reproduce and survive which eventually leads to them becoming the majority. Natural selection is only a force for populations, not individual organisms. This is a crucial distinction from the Lamarckian theory of evolution which holds that animals acquire traits through use or lack of use. For instance, if a Giraffe's neck grows longer due to reaching out to catch prey and its offspring will inherit a larger neck. The difference in neck size between generations will continue to grow until the giraffe is no longer able to breed with other giraffes. Evolution through Genetic Drift In the process of genetic drift, alleles at a gene may be at different frequencies within a population by chance events. At some point, one will reach fixation (become so widespread that it is unable to be eliminated through natural selection), while the other alleles drop to lower frequencies. In the extreme it can lead to dominance of a single allele. The other alleles are eliminated, and heterozygosity decreases to zero. In a small number of people this could lead to the complete elimination of the recessive gene. This is known as the bottleneck effect. It is typical of an evolution process that occurs when a large number individuals migrate to form a group. A phenotypic bottleneck can also occur when the survivors of a catastrophe like an outbreak or mass hunting event are confined to an area of a limited size. The survivors are likely to be homozygous for the dominant allele, meaning that they all have the same phenotype and therefore share the same fitness characteristics. This can be caused by war, earthquakes or even a plague. The genetically distinct population, if it is left, could be susceptible to genetic drift. Suggested Resource site , Lewens, and Ariew employ Lewens, Walsh and Ariew employ a “purely outcome-oriented” definition of drift as any departure from expected values for variations in fitness. They cite the famous example of twins that are genetically identical and share the same phenotype, but one is struck by lightning and dies, whereas the other lives to reproduce. This kind of drift can be vital to the evolution of a species. But, it's not the only way to evolve. The primary alternative is a process known as natural selection, where the phenotypic variation of a population is maintained by mutation and migration. Stephens claims that there is a major difference between treating drift as a force, or a cause and considering other causes of evolution such as mutation, selection and migration as causes or causes. He argues that a causal-process explanation of drift lets us separate it from other forces and that this distinction is essential. He also claims that drift is a directional force: that is, it tends to eliminate heterozygosity, and that it also has a specific magnitude which is determined by population size. Evolution through Lamarckism In high school, students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, often called “Lamarckism which means that simple organisms develop into more complex organisms through adopting traits that are a product of the organism's use and misuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher branches in the trees. This process would cause giraffes to give their longer necks to their offspring, who then get taller. Lamarck the French Zoologist from France, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. In his view living things evolved from inanimate matter through a series of gradual steps. Lamarck was not the first to suggest this but he was considered to be the first to give the subject a thorough and general overview. The predominant story is that Charles Darwin's theory on natural selection and Lamarckism fought in the 19th century. Darwinism ultimately prevailed, leading to what biologists refer to as the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead, it claims that organisms evolve through the influence of environment elements, like Natural Selection. Lamarck and his contemporaries endorsed the notion that acquired characters could be passed down to the next generation. However, this notion was never a major part of any of their evolutionary theories. This is due to the fact that it was never scientifically tested. It's been more than 200 years since Lamarck was born and, in the age of genomics there is a vast amount of evidence to support the possibility of inheritance of acquired traits. This is also known as “neo Lamarckism”, or more commonly epigenetic inheritance. This is a variant that is as reliable as the popular neodarwinian model. Evolution through Adaptation One of the most widespread misconceptions about evolution is that it is driven by a sort of struggle to survive. Suggested Resource site is a false assumption and ignores other forces driving evolution. The struggle for survival is more effectively described as a struggle to survive within a particular environment, which may involve not only other organisms, but also the physical environment. To understand how evolution works it is beneficial to consider what adaptation is. The term “adaptation” refers to any characteristic that allows living organisms to survive in its environment and reproduce. It could be a physiological feature, such as feathers or fur or a behavior, such as moving into shade in hot weather or coming out at night to avoid the cold. The capacity of a living thing to extract energy from its surroundings and interact with other organisms and their physical environments is essential to its survival. The organism needs to have the right genes to generate offspring, and it must be able to locate enough food and other resources. Furthermore, the organism needs to be able to reproduce itself at an optimal rate within its environmental niche. These factors, in conjunction with gene flow and mutations can result in an alteration in the ratio of different alleles in the population's gene pool. The change in frequency of alleles can result in the emergence of new traits, and eventually new species in the course of time. Many of the characteristics we admire in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from air feathers and fur as insulation long legs to run away from predators and camouflage to conceal. However, a thorough understanding of adaptation requires paying attention to the distinction between behavioral and physiological traits. Physiological adaptations, like thick fur or gills, are physical traits, while behavioral adaptations, such as the tendency to seek out companions or to move to the shade during hot weather, aren't. It is important to keep in mind that insufficient planning does not cause an adaptation. In fact, failure to think about the consequences of a behavior can make it unadaptable even though it might appear reasonable or even essential.