What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to evolve over time. This includes the appearance and development of new species.
Numerous examples have been offered of this, including various varieties of fish called sticklebacks that can live in either fresh or salt water and walking stick insect varieties that favor particular host plants. These mostly reversible trait permutations however, are not able to explain fundamental changes in basic body plans.
Evolution through Natural Selection
The development of the myriad living creatures on Earth is a mystery that has intrigued scientists for many centuries. Charles Darwin's natural selection is the most well-known explanation. This happens when people who are more well-adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, a group of well-adapted individuals expands and eventually becomes a new species.
Natural selection is an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity within the species. Inheritance is the transfer of a person's genetic characteristics to his or her offspring which includes both dominant and recessive alleles. Reproduction is the process of producing fertile, viable offspring. This can be achieved via sexual or asexual methods.
All of these elements must be in harmony to allow natural selection to take place. For instance, if a dominant allele at the gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will be more prominent in the population. However, if the allele confers an unfavorable survival advantage or reduces fertility, it will be eliminated from the population. The process is self reinforcing, which means that an organism with an adaptive characteristic will live and reproduce more quickly than those with a maladaptive trait. The more fit an organism is as measured by its capacity to reproduce and survive, is the greater number of offspring it can produce. People with good characteristics, such as the long neck of giraffes, or bright white patterns on male peacocks are more likely than others to live and reproduce which eventually leads to them becoming the majority.
Natural selection is only a factor in populations and not on individuals. This is an important distinction from the Lamarckian theory of evolution, which claims that animals acquire traits by use or inactivity. For instance, if the Giraffe's neck grows longer due to stretching to reach prey, its offspring will inherit a more long neck. The length difference between generations will persist until the neck of the giraffe becomes too long to not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles of a gene are randomly distributed in a group. Eventually, one of them will reach fixation (become so common that it is unable to be removed by natural selection) and other alleles will fall to lower frequency. This can lead to an allele that is dominant in the extreme. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small number of people it could lead to the complete elimination of the recessive allele. This scenario is called the bottleneck effect. It is typical of the evolutionary process that occurs when a large number individuals migrate to form a population.
A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe like an outbreak or mass hunt incident are concentrated in an area of a limited size. The survivors will carry an allele that is dominant and will have the same phenotype. This situation could be caused by earthquakes, war or even a plague. The genetically distinct population, if it remains vulnerable to genetic drift.
Walsh Lewens and Ariew utilize a "purely outcome-oriented" definition of drift as any departure from expected values for different fitness levels. They provide the famous case of twins who are both genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, while the other is able to reproduce.
This kind of drift can play a significant part in the evolution of an organism. It is not the only method of evolution. The primary alternative is a process known as natural selection, where the phenotypic variation of the population is maintained through mutation and migration.
Stephens argues that there is a big difference between treating drift as a force or a cause and treating other causes of evolution, such as mutation, selection, and migration as forces or causes. He argues that a causal-process model of drift allows us to 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 specific magnitude which is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is generally called "Lamarckism" and it states that simple organisms grow into more complex organisms via the inherited characteristics that are a result of an organism's natural activities use and misuse. Lamarckism can be illustrated by an giraffe's neck stretching to reach higher branches in the trees. 에볼루션코리아 could cause giraffes to give their longer necks to their offspring, who would then become taller.
Lamarck was a French Zoologist. In his lecture to begin his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced an innovative concept that completely challenged the previous understanding of organic transformation. According to Lamarck, living creatures evolved from inanimate matter by a series of gradual steps. Lamarck was not the first to suggest that this might be the case, but the general consensus is that he was the one giving the subject its first general and comprehensive treatment.
The predominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th Century. Darwinism eventually triumphed, leading to the development of what biologists refer to as the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be acquired through inheritance and instead suggests that organisms evolve by the symbiosis of environmental factors, such as natural selection.
Although Lamarck endorsed the idea of inheritance through acquired characters, and 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 validated scientifically.
It's been more than 200 years since Lamarck was born and, in the age of genomics, there is a large amount of evidence that supports the heritability of acquired characteristics. It is sometimes called "neo-Lamarckism" or, more commonly, epigenetic inheritance. It is a version of evolution that is as valid as the more popular Neo-Darwinian model.
Evolution by adaptation
One of the most popular misconceptions about evolution is being driven by a fight for survival. This view is a misrepresentation of natural selection and ignores the other forces that drive evolution. The fight for survival can be more accurately described as a struggle to survive in a specific environment. This can be a challenge for not just other living things as well as the physical environment.
Understanding how adaptation works is essential to understand evolution. It is a feature that allows a living thing to live in its environment and reproduce. It could be a physiological feature, such as fur or feathers or a behavior like moving into the shade in hot weather or coming out at night to avoid cold.
The capacity of a living thing to extract energy from its surroundings and interact with other organisms as well as their physical environment, is crucial to its survival. The organism needs to have the right genes to generate offspring, and it must be able to access enough food and other resources. The organism should be able to reproduce at an amount that is appropriate for its specific niche.
These elements, in conjunction with gene flow and mutation result in a change in the proportion of alleles (different varieties of a particular gene) in a population's gene pool. Over time, this change in allele frequency can lead to the emergence of new traits, and eventually new species.
A lot of the traits we admire in animals and plants are adaptations, for example, lung or gills for removing oxygen from the air, fur or feathers for insulation and long legs for running away from predators and camouflage for hiding. However, a proper understanding of adaptation requires attention to the distinction between physiological and behavioral characteristics.
Physiological traits like thick fur and gills are physical traits. The behavioral adaptations aren't an exception, for instance, the tendency of animals to seek out companionship or retreat into shade during hot weather. It is also important to remember that a lack of planning does not cause an adaptation. In fact, failure to consider the consequences of a behavior can make it unadaptive even though it may appear to be reasonable or even essential.