What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to evolve over time. This includes the appearance and development of new species.
A variety of examples have been provided of this, including various varieties of fish called sticklebacks that can live in salt or fresh water, as well as walking stick insect varieties that prefer particular host plants. These are mostly reversible traits, however, cannot explain fundamental changes in basic body plans.
Evolution by Natural Selection
The development of the myriad living organisms on Earth is a mystery that has fascinated scientists for many centuries. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when those who are better adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, the population of individuals who are well-adapted grows and eventually develops into an entirely new species.
Natural selection is a process that is cyclical 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 an animal species. Inheritance is the transfer of a person's genetic characteristics to his or her offspring, which includes both recessive and dominant alleles. Reproduction is the process of creating fertile, viable offspring. This can be achieved by both asexual or sexual methods.
Natural selection is only possible when all of these factors are in balance. If, for instance, a dominant gene allele causes an organism reproduce and survive more than the recessive allele then the dominant allele becomes more prevalent in a population. But if the allele confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. This process is self-reinforcing meaning that an organism that has an adaptive trait will live and reproduce far more effectively than those with a maladaptive trait. The more fit an organism is which is measured by its ability to reproduce and survive, is the more offspring it will produce. People with desirable characteristics, such as having a long neck in the giraffe, or bright white patterns on male peacocks, are more likely than others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection only affects populations, not on individuals. This is a major distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or disuse. If a giraffe extends its neck in order to catch prey and the neck grows larger, then its offspring will inherit this characteristic. The difference in neck size between generations will increase until the giraffe becomes unable to breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a group. In the end, only one will be fixed (become common enough to no more be eliminated through natural selection) and the rest of the alleles will decrease in frequency. In the extreme this, it leads to a single allele dominance. Other alleles have been virtually eliminated and heterozygosity diminished to a minimum. In a small population, this could lead to the complete elimination of the recessive allele. This is called a bottleneck effect, and it is typical of the kind of evolutionary process when a large number of individuals move to form a new group.
A phenotypic bottleneck may happen when the survivors of a catastrophe, such as an epidemic or a mass hunting event, are concentrated into a small area. The survivors will have a dominant allele and thus will have the same phenotype. This may be the result of a war, an earthquake, or even a plague. Regardless of the cause the genetically distinct population that is left might be susceptible to genetic drift.
Walsh Lewens and Ariew use Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any departure from the expected values of differences in fitness. They cite the famous example of twins who are both genetically identical and have exactly the same phenotype. However, one is struck by lightning and dies, while the other continues to reproduce.
This type of drift is crucial in the evolution of a species. However, it's not the only way to develop. The most common alternative is a process called natural selection, where the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens argues that there is a significant difference between treating drift as a force or a cause and considering other causes of evolution such as mutation, selection and migration as causes or causes. He argues that a causal-process explanation of drift lets us distinguish it from other forces and that this distinction is crucial. He also claims that drift has a direction, that is, it tends to eliminate heterozygosity. It also has a size, which is determined by population size.
Evolution through Lamarckism
Biology students in high school are frequently introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism" is based on the idea that simple organisms transform into more complex organisms through taking on traits that are a product of an organism's use and disuse. Lamarckism is typically illustrated by the image of a giraffe that extends its neck to reach the higher branches in the trees. This causes giraffes' longer necks to be passed onto their offspring who would then grow even taller.
Lamarck Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the conventional wisdom on organic transformation. In his opinion living things had evolved from inanimate matter through the gradual progression of events. Lamarck was not the first to make this claim but he was regarded as the first to offer the subject a thorough and general overview.
The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th Century. Darwinism eventually won and led to the development of what biologists now call the Modern Synthesis. The theory argues that traits acquired through evolution can be inherited and instead, it argues that organisms develop by the symbiosis of environmental factors, including natural selection.
While Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries paid lip-service to this notion but it was not an integral part of any of their evolutionary theories. This is due to the fact that it was never scientifically tested.
It's been over 200 years since the birth of Lamarck, and in the age genomics, there is a growing evidence-based body of evidence to support the heritability acquired characteristics. This is often called "neo-Lamarckism" or, more commonly, epigenetic inheritance. It is a version of evolution that is as relevant as the more popular neo-Darwinian model.
Evolution by adaptation
One of the most popular misconceptions about evolution is that it is being driven by a struggle for survival. This notion is not true and ignores other forces driving evolution. The fight for survival can be more accurately described as a struggle to survive within a specific environment, which may include not just other organisms, but also the physical environment.
Understanding the concept of adaptation is crucial to understand evolution. It refers to a specific feature that allows an organism to survive and reproduce in its environment. It can be a physiological structure, 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 the cold.
The survival of an organism is dependent on its ability to extract energy from the environment and interact with other organisms and their physical environments. The organism should possess the right genes to create offspring and to be able to access enough food and resources. The organism must also be able reproduce itself at an amount that is appropriate for its niche.
These factors, together with mutation and gene flow, lead to changes in the ratio of alleles (different varieties of a particular gene) in the gene pool of a population. Over time, this change in allele frequencies could result in the emergence of new traits and eventually new species.
Many of the characteristics we admire in animals and plants are adaptations, for example, the lungs or gills that extract oxygen from the air, feathers or fur to provide insulation, long legs for running away from predators and camouflage to hide. However, a proper understanding of adaptation requires attention to the distinction between physiological and Www.Evolutionkr.Kr behavioral traits.
Physical traits such as the thick fur and gills are physical characteristics. Behavior adaptations aren't an exception, for instance, the tendency of animals to seek companionship or move into the shade during hot temperatures. It is also important to note that insufficient planning does not cause an adaptation. Inability to think about the consequences of a decision, even if it appears to be logical, can cause it to be unadaptive.