What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to evolve over time. This includes the development of new species and the change in appearance of existing species.
This has been demonstrated by many examples such as the stickleback fish species that can live in fresh or saltwater and walking stick insect species that have a preference for particular host plants. These reversible traits can't, however, be the reason for fundamental changes in 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, which occurs when better-adapted individuals survive and reproduce more successfully than those who are less well adapted. As time passes, a group of well-adapted individuals increases and eventually becomes a new species.
Natural selection is an ongoing process and involves the interaction of three factors that are: reproduction, variation and inheritance. Mutation and sexual reproduction increase genetic diversity in the species. Inheritance refers to the passing of a person's genetic characteristics to their offspring that includes recessive and dominant alleles. Reproduction is the process of creating fertile, viable offspring. This can be achieved by both asexual or sexual methods.
All of these elements must be in balance to allow natural selection to take place. For example when a dominant allele at one gene allows an organism to live and reproduce more often than the recessive allele the dominant allele will be more common within the population. But if the allele confers an unfavorable survival advantage or reduces fertility, it will disappear from the population. The process is self reinforcing which means that an organism with an adaptive trait will survive and reproduce more quickly than one with a maladaptive characteristic. The more offspring an organism can produce the better its fitness that is determined by its capacity to reproduce itself and live. People with desirable traits, like 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 only affects populations, not individuals. This is a major distinction from the Lamarckian theory of evolution, which claims that animals acquire characteristics through use or disuse. For example, if a Giraffe's neck grows longer due to stretching to reach prey 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 reproduce with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a group. At some point, one will reach fixation (become so widespread that it is unable to be removed by natural selection) and the other alleles drop to lower frequency. In the extreme this, it leads to dominance of a single allele. The other alleles are eliminated, and heterozygosity decreases to zero. In a small group, this could lead to the complete elimination of recessive alleles. This scenario is called the bottleneck effect. It is typical of an evolutionary process that occurs whenever an enormous number of individuals move to form a group.
에볼루션 슬롯게임 ' can also occur when the survivors of a disaster such as an outbreak or a mass hunting event are confined to a small area. The survivors will have a dominant allele and thus will have the same phenotype. This could be caused by earthquakes, war or even plagues. Whatever the reason the genetically distinct population that remains could be susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from expected values for differences in fitness. They give the famous example of twins who are genetically identical and share the same phenotype. However one is struck by lightning and dies, but the other continues to reproduce.
This kind of drift could play a crucial role in the evolution of an organism. However, it's not the only way to develop. The main alternative is to use a process known as natural selection, where phenotypic variation in an individual is maintained through mutation and migration.
Stephens argues there is a significant difference between treating drift like a force or cause, and treating other causes such as migration and selection as causes and forces. He claims that a causal-process explanation of drift lets us separate it from other forces and that this differentiation is crucial. He further argues that drift has direction, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by the size of the population.
Evolution by Lamarckism
Biology students in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism which means that simple organisms evolve into more complex organisms by adopting traits that result from the organism's use and misuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher levels of leaves in the trees. This causes the necks of giraffes that are longer to be passed onto their offspring who would then grow even taller.
Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th of May in 1802, he presented an original idea that fundamentally challenged the previous understanding of organic transformation. In his view living things had evolved from inanimate matter through an escalating series of steps. Lamarck was not the only one to suggest that this might be the case but the general consensus is that he was the one having given the subject its first broad and comprehensive analysis.
The most popular story is that Charles Darwin's theory on natural selection and Lamarckism were rivals in the 19th century. Darwinism eventually triumphed and led to the development of what biologists today refer to as the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead argues that organisms evolve through the selective action of environment factors, including Natural Selection.
Lamarck and his contemporaries believed in the idea that acquired characters could be passed on to future generations. However, this notion was never a major part of any of their evolutionary theories. This is partly because it was never tested scientifically.
It has been more than 200 year since Lamarck's birth and in the field of genomics there is a growing evidence base that supports the heritability-acquired characteristics. This is referred to as "neo Lamarckism", or more generally epigenetic inheritance. It is a form of evolution that is just as valid as the more popular Neo-Darwinian theory.
Evolution through the process of adaptation
One of the most commonly-held misconceptions about evolution is being driven by a struggle for survival. This view is inaccurate and overlooks other forces that drive evolution. The struggle for survival is more precisely described as a fight to survive within a specific environment, which may be a struggle that involves not only other organisms but as well the physical environment.
Understanding the concept of adaptation is crucial to comprehend evolution. Adaptation refers to any particular characteristic that allows an organism to live and reproduce within its environment. It could be a physiological feature, such as fur or feathers or a behavior such as a tendency to move to the shade during hot weather or stepping out at night to avoid cold.
The survival of an organism is dependent on its ability to extract energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism must possess the right genes to create offspring, and it should be able to locate enough food and other resources. In addition, the organism should be capable of reproducing itself at an optimal rate within its environment.
These factors, together with mutations and gene flow, can lead to an alteration in the ratio of different alleles in the gene pool of a population. Over time, this change in allele frequency can result in the development of new traits and ultimately new species.
Many of the features that we admire about animals and plants are adaptations, for example, the lungs or gills that extract oxygen from the air, fur or feathers to provide insulation long legs to run away from predators and camouflage to hide. To understand adaptation it is essential to discern between physiological and behavioral characteristics.
Physical characteristics like the thick fur and gills are physical traits. Behavior adaptations aren't an exception, for instance, the tendency of animals to seek companionship or retreat into shade in hot weather. It is also important to keep in mind that lack of planning does not cause an adaptation. In fact, failing to think about the implications of a behavior can make it unadaptive despite the fact that it appears to be logical or even necessary.