What is Free Evolution?<br /><br />Free evolution is the concept that the natural processes of organisms can lead them to evolve over time. This includes the appearance and growth of new species.<br /><br />Many examples have been given of this, including different kinds of stickleback fish that can live in either salt or fresh water, and walking stick insect varieties that prefer particular host plants. These reversible traits however, are not able to explain fundamental changes in basic body plans.<br /><br />Evolution by Natural Selection<br /><br />The development of the myriad of living organisms on Earth is an enigma that has intrigued scientists for many centuries. The most well-known explanation is Darwin's natural selection process, a process that occurs when individuals that are better adapted survive and reproduce more effectively than those who are less well adapted. As time passes, the number of well-adapted individuals becomes larger and eventually creates a new species.<br /><br />Natural selection is a cyclical process that is characterized by the interaction of three elements: variation, inheritance and reproduction. Mutation and sexual reproduction increase the genetic diversity of the species. Inheritance refers to the transmission of a person’s genetic traits, which include both dominant and recessive genes to their offspring. Reproduction is the process of creating fertile, viable offspring. This can be done via sexual or asexual methods.<br /><br /><a href="https://evolutionkr.kr/">evolutionkr</a> of these variables must be in harmony to allow natural selection to take place. If, for instance an allele of a dominant gene makes an organism reproduce and live longer than the recessive gene allele The dominant allele becomes more prevalent in a population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. The process is self-reinforcing, which means that an organism with an adaptive trait will survive and reproduce more quickly than those with a maladaptive feature. The more offspring an organism can produce the better its fitness, which is measured by its ability to reproduce and survive. People with desirable traits, like a longer neck in giraffes and bright white color patterns in male peacocks are more likely survive and have offspring, and thus will make up the majority of the population in the future.<br /><br />Natural selection only acts on populations, not on individuals. This is a significant distinction from the Lamarckian theory of evolution, which states that animals acquire characteristics through use or neglect. For instance, if a giraffe's neck gets longer through stretching to reach prey, its offspring will inherit a larger neck. The differences in neck size between generations will increase until the giraffe is unable to breed with other giraffes.<br /><br />Evolution through Genetic Drift<br /><br />In genetic drift, alleles within a gene can reach different frequencies in a population by chance events. At some point, one will reach fixation (become so widespread that it cannot be eliminated through natural selection), while the other alleles drop to lower frequency. In the extreme it can lead to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small group this could lead to the complete elimination of the recessive gene. 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.<br /><br />A phenotypic bottleneck may also occur when survivors of a disaster like an outbreak or mass hunt event are concentrated in a small area. The remaining individuals will be mostly homozygous for the dominant allele which means that they will all share the same phenotype and will therefore have the same fitness traits. This can be caused by war, earthquakes, or even plagues. Whatever the reason the genetically distinct group that remains could be susceptible to genetic drift.<br /><br />Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected value due to differences in fitness. They give the famous example of twins that are genetically identical and share the same phenotype. However, one is struck by lightning and dies, but the other continues to reproduce.<br /><br />This kind of drift could be vital to the evolution of a species. This isn't the only method for evolution. The main alternative is a process called natural selection, where the phenotypic variation of the population is maintained through mutation and migration.<br /><br />Stephens asserts that there is a vast distinction between treating drift as an actual cause or force, and treating other causes such as selection mutation and migration as causes and forces. He argues that a causal-process model of drift allows us to separate it from other forces, and this distinction is crucial. He also claims that drift has a direction, that is it tends to reduce heterozygosity. It also has a magnitude, that is determined by the size of the population.<br /><br />Evolution by Lamarckism<br /><br />Biology students in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is generally called "Lamarckism" and it states that simple organisms develop into more complex organisms through the inherited characteristics that result from the organism's natural actions, use and disuse. Lamarckism can be demonstrated by a giraffe extending its neck to reach higher levels of leaves in the trees. This could cause giraffes' longer necks to be passed to their offspring, who would grow taller.<br /><br />Lamarck was a French zoologist and, in his opening 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. In his opinion living things evolved from inanimate matter via a series of gradual steps. Lamarck wasn't the first to suggest this, but he was widely thought of as the first to offer the subject a thorough and general treatment.<br /><br />The dominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were competing in the 19th century. Darwinism eventually triumphed, leading to the development of what biologists now refer to as the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead, it claims that organisms evolve through the influence of environment factors, including Natural Selection.<br /><br />While Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries spoke of this idea but it was not a central element in any of their evolutionary theories. This is due in part to the fact that it was never tested scientifically.<br /><br />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 acquired characteristics. This is also known 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 model.<br /><br />Evolution by adaptation<br /><br />One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle to survive. This notion is not true and overlooks other forces that drive evolution. The struggle for existence is better described as a fight to survive in a certain environment. This may include not only other organisms but also the physical surroundings themselves.<br /><br /><br /><br />Understanding the concept of adaptation is crucial to understand evolution. The term "adaptation" refers to any characteristic that allows a living thing to live in its environment and reproduce. It could be a physical feature, such as feathers or fur. Or it can be a behavior trait that allows you to move to the shade during the heat, or coming out to avoid the cold at night.<br /><br />The survival of an organism depends on its ability to obtain energy from the environment and to interact with other living organisms and their physical surroundings. The organism should possess the right genes to produce offspring and to be able to access sufficient food and resources. The organism should be able to reproduce at a rate that is optimal for its particular niche.<br /><br />These elements, in conjunction with mutation and gene flow can result in changes in the ratio of alleles (different varieties of a particular gene) in a population's gene pool. This shift in the frequency of alleles can lead to the emergence of novel traits and eventually, new species as time passes.<br /><br />A lot of the traits we admire in plants and animals are adaptations. For example, lungs or gills that extract oxygen from air feathers and fur for insulation and long legs to get away from predators and camouflage for hiding. However, a proper understanding of adaptation requires attention to the distinction between physiological and behavioral characteristics.<br /><br />Physiological adaptations, such as thick fur or gills, are physical characteristics, whereas behavioral adaptations, such as the tendency to search for companions or to move into the shade in hot weather, aren't. It is important to remember that a the absence of planning doesn't make an adaptation. Failure to consider the effects of a behavior, even if it appears to be rational, may cause it to be unadaptive.<br /><br />