What is Free Evolution?
Free evolution is the concept that natural processes can lead to the development of organisms over time. This includes the development of new species and the alteration of the appearance of existing species.
This is evident in numerous examples, including stickleback fish varieties that can be found in fresh or saltwater and walking stick insect types that prefer specific host plants. These reversible traits, however, cannot explain fundamental changes in body plans.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all living creatures that inhabit our planet for ages. The most well-known explanation is that of Charles Darwin's natural selection process, an evolutionary process that 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 expands and eventually forms a whole new species.
Natural selection is an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity within a species. Inheritance is the transfer of a person's genetic characteristics to the offspring of that person which includes both dominant and recessive alleles. Reproduction is the process of producing viable, fertile offspring. This can be accomplished by both asexual or sexual methods.
Natural selection only occurs when all the factors are in equilibrium. If,
에볼루션 바카라 무료체험 for example,
에볼루션게이밍 a dominant gene allele causes an organism reproduce and last longer than the recessive allele then the dominant allele becomes more prevalent in a population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will be eliminated. This process is self-reinforcing which means that an organism that has an adaptive characteristic will live and reproduce much more than those with a maladaptive feature. The greater an organism's fitness, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with desirable traits, such as a longer neck in giraffes or bright white color patterns in male peacocks are more likely to survive and produce offspring,
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Natural selection only acts on populations, not on individual organisms. This is a significant distinction from the Lamarckian theory of evolution, which states that animals acquire traits due to use or lack of use. For instance, if a giraffe's neck gets longer through stretching to reach prey and its offspring will inherit a longer neck. The differences in neck length between generations will persist until the giraffe's neck gets too long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles of a gene could attain different frequencies in a group by chance events. At some point, only one of them will be fixed (become widespread enough to not longer be eliminated through natural selection), and the other alleles decrease in frequency. In extreme cases this, it leads to a single allele dominance. The other alleles are eliminated, and heterozygosity decreases to zero. In a small number of people this could lead to 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 takes place when a large number of people migrate to form a new group.
A phenotypic bottleneck can also occur when the survivors of a catastrophe like an epidemic or a mass hunting event, are condensed within a narrow area. The surviving individuals will be largely homozygous for the dominant allele meaning that they all have the same phenotype and consequently have the same fitness characteristics. This can be caused by earthquakes, war or even a plague. The genetically distinct population, if it remains, could be susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They cite a famous instance of twins who are genetically identical, share the exact same phenotype but one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift can play a crucial part in the evolution of an organism. But, it's not the only way to develop. The primary alternative is a process called natural selection, where phenotypic variation in a population is maintained by mutation and
에볼루션바카라사이트 migration.
Stephens asserts that there is a significant difference between treating the phenomenon of drift as a force or as a cause and treating other causes of evolution, such as mutation, selection, and migration as forces or causes. He argues that a causal mechanism account of drift allows us to distinguish it from the other forces, 에볼루션 바카라 무료체험 (
http://taikwu.com.tw/dsz/home.php?Mod=space&uid=1324020) and this distinction is crucial. He argues further that drift has direction, i.e., it tends to eliminate heterozygosity. It also has a size that is determined by the size of the population.
Evolution by Lamarckism
Students of biology in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism, states that simple organisms evolve into more complex organisms taking on traits that are a product of an organism's use and disuse. Lamarckism is typically illustrated by the image of a giraffe stretching its neck further to reach higher up in the trees. This could result in giraffes passing on their longer necks to their offspring, who then grow even taller.
Lamarck Lamarck, a French zoologist, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. In his view, 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 general and thorough treatment.
The most popular story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were rivals in the 19th Century. Darwinism eventually won and led to the development of what biologists call the Modern Synthesis. The theory denies that acquired characteristics are passed down from generation to generation and instead argues that organisms evolve through the influence of environment factors, including Natural Selection.
Lamarck and his contemporaries believed in the notion that acquired characters could be passed on to the next generation. However, this idea was never a central part of any of their evolutionary theories. This is partly due to the fact that it was never tested scientifically.
However, it has been more than 200 years since Lamarck was born and in the age of genomics there is a huge amount of evidence to support the heritability of acquired characteristics. This is referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model.
Evolution by the process of adaptation
One of the most common misconceptions about evolution is that it is being driven by a struggle to survive. In fact, this view is a misrepresentation of natural selection and ignores the other forces that drive evolution.