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What is Free Evolution? Free evolution is the concept that natural processes can cause organisms to evolve over time. This includes the emergence and development of new species. This is evident in numerous examples, including stickleback fish varieties that can live in saltwater or fresh water and walking stick insect varieties that are apprehensive about particular host plants. These reversible traits are not able to explain fundamental changes to basic body plans. Evolution through Natural Selection Scientists have been fascinated by the evolution of all living creatures that live on our planet for centuries. The best-established explanation is Darwin's natural selection process, a process that occurs when better-adapted individuals survive and reproduce more effectively than those less well adapted. Over time, the population of well-adapted individuals grows and eventually develops into a new species. Natural selection is a process that is cyclical and involves the interaction of three factors including reproduction, variation and inheritance. Sexual reproduction and mutations increase genetic diversity in the species. Inheritance refers to the transmission of a person’s genetic traits, which include recessive and dominant genes, to their offspring. Reproduction is the process of generating viable, fertile offspring. This can be achieved via sexual or asexual methods. All of these elements have to be in equilibrium for natural selection to occur. If, for instance, a dominant gene allele causes an organism reproduce and survive more than the recessive gene allele, then the dominant allele will become more prevalent in a population. But if the allele confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. The process is self-reinforcing, meaning that an organism with a beneficial characteristic is more likely to survive and reproduce than one with an unadaptive characteristic. The more offspring an organism can produce, the greater its fitness, which is measured by its capacity to reproduce itself and survive. Individuals with favorable characteristics, such as a long neck in giraffes, or bright white patterns on male peacocks are more likely than others to live and reproduce, which will eventually lead to them becoming the majority. Natural selection is an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution which claims that animals acquire traits through use or disuse. For example, if a animal's neck is lengthened by reaching out to catch prey and its offspring will inherit a larger neck. The difference in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes. Evolution by Genetic Drift In the process of genetic drift, alleles at a gene may reach different frequencies in a group by chance events. At some point, one will reach fixation (become so widespread that it cannot be eliminated by natural selection), while other alleles fall to lower frequencies. This can result in a dominant allele in the extreme. The other alleles have been basically eliminated and heterozygosity has diminished to zero. In a small population it could lead to the total elimination of recessive alleles. This is known as the bottleneck effect and is typical of the evolutionary process that occurs when the number of individuals migrate to form a group. A phenotypic bottleneck can also occur when the survivors of a catastrophe like an epidemic or mass hunt, are confined within a narrow area. The remaining individuals will be largely homozygous for the dominant allele which means they will all have the same phenotype and will thus share the same fitness characteristics. This may be caused by conflict, earthquake, or even a plague. Regardless of the cause the genetically distinct group that remains is susceptible to genetic drift. Walsh Lewens, Walsh, and Ariew define drift as a deviation from expected values due to differences in fitness. They give a famous example of twins that 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 could be very important in the evolution of an entire species. However, it's not the only way to evolve. Natural selection is the primary alternative, where mutations and migration maintain phenotypic diversity within the population. Stephens claims that there is a significant distinction between treating drift as a force or cause, and considering other causes, such as migration and selection mutation as causes and forces. He argues that a causal-process model of drift allows us to differentiate it from other forces and this distinction is crucial. 에볼루션카지노 argues further that drift has a direction, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by population size. Evolution by Lamarckism When students in high school take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 – 1829). His theory of evolution, often called “Lamarckism, states that simple organisms develop into more complex organisms through adopting traits that are a product of an organism's use and disuse. Lamarckism is usually illustrated with the image of a giraffe that extends its neck longer to reach higher up in the trees. This would cause the necks of giraffes that are longer to be passed on to their offspring who would grow taller. Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced a groundbreaking concept that radically challenged the conventional wisdom about organic transformation. In his opinion living things evolved from inanimate matter through an escalating series of steps. Lamarck wasn't the first to suggest this but he was considered to be the first to offer the subject a thorough and general treatment. The prevailing story is that Lamarckism was a rival to Charles Darwin's theory of evolutionary natural selection and that the two theories battled out in the 19th century. Darwinism ultimately won, leading to what biologists refer to as the Modern Synthesis. The theory argues that acquired characteristics can be acquired through inheritance and instead, it argues that organisms develop by the symbiosis of environmental factors, including natural selection. While Lamarck supported the notion of inheritance through acquired characters, and his contemporaries also offered a few words about this idea however, it was not a central element in any of their evolutionary theories. This is due to the fact that it was never scientifically validated. It has been more than 200 year since Lamarck's birth and in the field of genomics, there is an increasing body of evidence that supports the heritability of acquired traits. This is referred to as “neo Lamarckism”, or more generally epigenetic inheritance. It is a variant of evolution that is just as valid as the more popular Neo-Darwinian theory. Evolution through the process of adaptation One of the most widespread misconceptions about evolution is that it is driven by a type of struggle to survive. This view is inaccurate and ignores other forces driving evolution. The fight for survival can be more precisely described as a fight to survive in a specific environment, which can involve not only other organisms but as well the physical environment. Understanding the concept of adaptation is crucial to understand evolution. It is a feature that allows a living organism to live in its environment and reproduce. It could be a physiological feature, such as feathers or fur or a behavioral characteristic such as a tendency to move into shade in hot weather or coming out at night to avoid the cold. The survival of an organism is dependent on its ability to obtain energy from the environment and to interact with other living organisms and their physical surroundings. The organism needs to have the right genes to create offspring, and it must be able to find sufficient food and other resources. Moreover, the organism must be capable of reproducing itself at an optimal rate within its environmental niche. These factors, together with mutation and gene flow result in changes in the ratio of alleles (different varieties of a particular gene) in the gene pool of a population. This shift in the frequency of alleles can result in the emergence of new traits and eventually new species as time passes. A lot of the traits we admire in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from the air feathers and fur for insulation and long legs to get away from predators, and camouflage to hide. To understand the concept of adaptation, it is important to differentiate between physiological and behavioral traits. Physical characteristics like the thick fur and gills are physical characteristics. The behavioral adaptations aren't like the tendency of animals to seek out companionship or move into the shade in hot temperatures. In addition, it is important to note that a lack of forethought does not mean that something is an adaptation. In fact, failing to think about the implications of a choice can render it unadaptable despite the fact that it appears to be sensible or even necessary.