What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to develop over time. This includes the emergence and development of new species.
A variety of examples have been provided of this, including different varieties of stickleback fish that can live in salt or fresh water, and walking stick insect varieties that are attracted to particular host plants. These reversible traits however, are not able to be the reason for fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad of living creatures on Earth is a mystery that has fascinated scientists for centuries. The most well-known explanation is Darwin's natural selection,
무료에볼루션 a process that is triggered when more well-adapted individuals live longer and reproduce more effectively than those who are 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 including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity of the species. Inheritance is the passing of a person's genetic traits to their offspring which includes both recessive and dominant alleles. Reproduction is the process of producing viable, fertile offspring. This can be done by both asexual or sexual methods.
All of these variables must be in harmony for natural selection to occur. If, for example, a dominant gene allele allows an organism to reproduce and
바카라 에볼루션 survive more than the recessive gene The dominant allele is more prevalent in a population. If the allele confers a negative survival advantage or reduces the fertility of the population, it will go away. The process is self reinforcing meaning that an organism that has an adaptive characteristic will live and reproduce much more than those with a maladaptive trait. The more offspring an organism can produce the better its fitness that is determined by its ability to reproduce itself and live. People with good traits, like the long neck of giraffes, or bright white patterns on male peacocks are more likely to others to live and reproduce and 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 argues that animals acquire traits through use or disuse. For instance, if the animal's neck is lengthened by reaching out to catch prey, its offspring will inherit a longer neck. The length difference between generations will persist until the neck of the giraffe becomes so 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 be at different frequencies in a group through random events. At some point, one will reach fixation (become so widespread that it can no longer be removed through natural selection), while the other alleles drop to lower frequencies. This can lead to dominance in the extreme. Other alleles have been basically eliminated and heterozygosity has been reduced to a minimum. In a small population, this could lead to the complete elimination of recessive allele. This scenario is known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs 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 outbreak or a mass hunting event are concentrated in the same area. The remaining individuals will be mostly homozygous for the dominant allele which means they will all have the same phenotype and therefore have the same fitness characteristics. This situation might be caused by a war, an earthquake or even a disease. Whatever the reason the genetically distinct group that is left might be susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected values due to differences in fitness. They cite the famous example of twins that are genetically identical and
에볼루션 share the same phenotype, but one is struck by lightning and dies, whereas the other continues to reproduce.
This kind of drift can play a very important part in the evolution of an organism. However, it is not the only method to evolve. The primary alternative is to use a process known as natural selection, in which the phenotypic diversity of the population is maintained through mutation and migration.
Stephens asserts that there is a significant distinction between treating drift as an actual cause or force, and considering other causes, such as selection mutation and migration as causes and forces. Stephens claims that a causal process explanation of drift lets us distinguish it from other forces and this distinction is crucial. He further argues that drift is a directional force: that is it tends to eliminate heterozygosity, and that it also has a size, which is determined by population size.
Evolution through Lamarckism
Biology students in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism", states that simple organisms transform into more complex organisms through taking on traits that result from the organism's use and misuse. Lamarckism is typically illustrated with the image of a giraffe stretching its neck to reach the higher branches in the trees. This could cause giraffes' longer necks to be passed onto their offspring who would then grow even taller.
Lamarck,
에볼루션카지노 a French Zoologist, introduced an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. According to Lamarck, living creatures evolved from inanimate material by a series of gradual steps. Lamarck was not the first to suggest this however he was widely considered to be the first to offer the subject a thorough and general explanation.
The most popular story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were competing during the 19th century. Darwinism ultimately prevailed which led to what biologists refer to as the Modern Synthesis. The theory argues that traits acquired through evolution can be inherited and instead suggests that organisms evolve through the selective action of environmental factors, including natural selection.
Although Lamarck supported the notion of inheritance through acquired characters and
에볼루션게이밍 his contemporaries also offered a few words about this idea, it was never a major feature in any of their theories about evolution. This is largely 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 vast amount of evidence to support the heritability of acquired traits. This is often referred to as "neo-Lamarckism" or, more commonly epigenetic inheritance. It is a version of evolution that is just as relevant as the more popular neo-Darwinian model.
Evolution by adaptation
One of the most common misconceptions about evolution is being driven by a fight for survival. This view is inaccurate and overlooks the other forces that determine the rate of evolution. The fight for survival can be more effectively described as a struggle to survive within a particular environment, which could include not just other organisms, but as well the physical environment.
Understanding the concept of adaptation is crucial to comprehend evolution.