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What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can cause them to develop over time. This includes the development of new species and the alteration of the appearance of existing ones.
This has been demonstrated by many examples such as the stickleback fish species that can thrive in salt or fresh water, and walking stick insect types that are apprehensive about specific host plants. These are mostly reversible traits however, are not able to explain fundamental changes in basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the evolution of all living organisms that inhabit our planet for many centuries. The most widely accepted explanation is Charles Darwin's natural selection, which occurs when individuals that are better adapted survive and reproduce more effectively than those less well-adapted. Over time, a community of well-adapted individuals increases and eventually creates a new species.
Natural selection is a cyclical process that involves the interaction of three factors that are inheritance, variation and reproduction. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity within the species. Inheritance is the term used to describe the transmission of a person's genetic traits, which include both dominant and recessive genes to their offspring. Reproduction is the generation of fertile, viable offspring which includes both asexual and sexual methods.
Natural selection can only occur when all these elements are in harmony. For instance when an allele that is dominant at the gene can cause an organism to live and reproduce more often than the recessive one, the dominant allele will become more common within the population. However, if the gene confers an unfavorable survival advantage or decreases fertility, it will disappear from the population. The process is self reinforcing which means that an organism that has an adaptive trait will survive and reproduce far more effectively than one with a maladaptive characteristic. The more offspring that an organism has the better its fitness, which is measured by its ability to reproduce itself and survive. People with good characteristics, such as a long neck in the giraffe, or bright white patterns on male peacocks are more likely to others to survive and reproduce, which will eventually lead to them becoming the majority.
Natural selection is a factor in populations and not on individuals. This is an important distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or disuse. For instance, if the Giraffe's neck grows longer due to reaching out to catch prey its offspring will inherit a longer neck. The length difference between generations will continue until the neck of the giraffe becomes too long that it can not breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when the alleles of a gene are randomly distributed in a group. Eventually, one of them will reach fixation (become so widespread that it is unable to be eliminated through natural selection), while other alleles will fall to lower frequency. This can result in a dominant allele in extreme. The other alleles are eliminated, and heterozygosity falls to zero. In a small group it could result in the complete elimination of recessive gene. Such a scenario would be known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs when a large amount of individuals migrate to form a new group.
A phenotypic bottleneck could happen when the survivors of a disaster like an epidemic or mass hunt, are confined in a limited area. The survivors will be mostly homozygous for the dominant allele meaning that they all have the same phenotype and will consequently share the same fitness characteristics. This can be caused by earthquakes, war or even plagues. The genetically distinct population, if left vulnerable to genetic drift.
Walsh, Lewens and Ariew define drift as a deviation from expected values due to differences in fitness. They cite a famous instance of twins who are genetically identical and have identical phenotypes, but one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could play a crucial role in the evolution of an organism. However, it is not the only way to develop. The primary alternative is to use a process known as natural selection, in which the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens claims that there is a big difference between treating drift as a force, or an underlying cause, and considering other causes of evolution like mutation, selection and migration as forces or causes. Stephens claims that a causal process explanation of drift lets us separate it from other forces, and this differentiation is crucial. He argues further that drift is both an orientation, i.e., it tends to reduce heterozygosity. It also has a size, that is determined by population size.
Evolution through Lamarckism
When high school students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is commonly known as "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of traits which result from an organism's natural activities usage, 바카라 에볼루션 바카라 사이트 (click through the up coming page) use and disuse. Lamarckism is usually illustrated with a picture of a giraffe that extends its neck longer to reach higher up in the trees. This could cause giraffes to pass on their longer necks to offspring, who then grow even taller.
Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. According to him, living things had evolved from inanimate matter via a series of gradual steps. Lamarck was not the only one to suggest that this might be the case but his reputation is widely regarded as being the one who gave the subject its first broad and thorough treatment.
The most popular story is that Lamarckism was an opponent to Charles Darwin's theory of evolution by natural selection and that the two theories fought out in the 19th century. Darwinism ultimately prevailed and led to what biologists call the Modern Synthesis. The theory argues that acquired traits can be passed down and instead argues that organisms evolve through the selective influence of environmental elements, like Natural Selection.
Lamarck and his contemporaries believed in the idea that acquired characters could be passed down to the next generation. However, this notion was never a major 에볼루션 사이트 part of any of their theories about evolution. This is due to the fact that it was never tested scientifically.
It's been more than 200 years since the birth of Lamarck and in the field of age genomics there is a growing evidence-based body of evidence to support the heritability acquired characteristics. This is sometimes called "neo-Lamarckism" or, more commonly epigenetic inheritance. This is a model that is just as valid as the popular Neodarwinian model.
Evolution through Adaptation
One of the most popular misconceptions about evolution is that it is being driven by a fight for survival. This is a false assumption and ignores other forces driving evolution. The struggle for survival is more accurately described as a struggle to survive within a specific environment, which could include not just other organisms, but as well the physical environment.
Understanding adaptation is important to understand evolution. The term "adaptation" refers to any characteristic that allows living organisms to survive in its environment and reproduce. It could be a physiological structure such as feathers or fur or a behavior, such as moving to the shade during hot weather or 에볼루션코리아 - ftp.best5.Ru, stepping out at night to avoid the cold.
The capacity of an organism to draw energy from its environment and interact with other organisms as well as their physical environment, is crucial to its survival. The organism should possess the right genes for producing offspring and be able find sufficient food and resources. Furthermore, the organism needs to be capable of reproducing at an optimal rate within its niche.
These factors, along with gene flow and mutation 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 could lead to the development of new traits, 에볼루션 바카라 and eventually, new species over time.
Many of the characteristics we admire in animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, fur or feathers for insulation, long legs for running away from predators, and camouflage for hiding. However, a proper understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills, are physical traits, whereas behavioral adaptations, like the tendency to seek out companions or to retreat into the shade in hot weather, aren't. Furthermore, it is important to remember that a lack of forethought does not mean that something is an adaptation. In fact, failing to think about the consequences of a choice can render it ineffective even though it may appear to be reasonable or even essential.