What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to develop over time. This includes the appearance and development of new species.
This has been proven by numerous examples such as the stickleback fish species that can live in fresh or saltwater and walking stick insect species that are apprehensive about particular host plants. These typically reversible traits cannot explain fundamental changes to the body's basic plans.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living creatures that live on our planet for ages. Charles Darwin's natural selection theory is the most well-known explanation. This process occurs when individuals who are better-adapted survive and reproduce more than those who are less well-adapted. Over time, the population of well-adapted individuals grows and eventually creates a new species.
Natural selection is an ongoing process that involves the interaction of three factors including inheritance, variation, and reproduction. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity within the species. Inheritance refers to the transmission of a person's genetic traits, including both dominant and recessive genes and their offspring. Reproduction is the process of creating viable, fertile offspring. This can be done by both asexual or sexual methods.
All of these elements must be in balance to allow natural selection to take place. If, for instance the dominant gene allele makes an organism reproduce and survive more than the recessive gene allele The dominant allele becomes more common in a population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will be eliminated. This process is self-reinforcing which means that an organism with an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive feature. The more offspring an organism produces the more fit it is, which is measured by its ability to reproduce and survive. Individuals with favorable traits, such as having a longer neck in giraffes or bright white color patterns in male peacocks, are more likely to survive and have offspring, so they will eventually make up the majority of the population in the future.
Natural selection is only an element in the population and not on individuals. This is a crucial distinction from the Lamarckian theory of evolution, which states that animals acquire traits either through use or lack of use. If a giraffe expands its neck in order to catch prey, and the neck becomes longer, then its offspring will inherit this trait. The differences in neck size between generations will continue to grow until the giraffe is unable to reproduce with other giraffes.
Evolution by Genetic Drift
In genetic drift, the alleles within a gene can attain different frequencies in a population through random events. Eventually, only one will be fixed (become widespread enough to not longer be eliminated through natural selection) and the other alleles diminish in frequency. In extreme cases this, it leads to dominance of a single allele. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small number of people this could result in the total elimination of recessive allele. This scenario is called the bottleneck effect and is typical of the evolution process that occurs when a large number individuals migrate to form a population.
A phenotypic bottleneck may occur when the survivors of a disaster, such as an epidemic or mass hunt, are confined into a small area. The remaining individuals will be largely homozygous for the dominant allele, meaning that they all share the same phenotype, and thus share the same fitness characteristics. This situation might be caused by war, an earthquake or even a disease. The genetically distinct population, if left susceptible to genetic drift.
Walsh, Lewens, and Ariew employ Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from expected values for variations in fitness. They provide a well-known 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 be vital to the evolution of the species. However, it is not the only method to develop. The primary alternative is a process called natural selection, in which the phenotypic variation of a population is maintained by mutation and migration.
Stephens claims that there is a significant difference between treating drift like an actual cause or force, and treating other causes like selection mutation and migration as causes and forces. He claims that a causal-process explanation of drift lets us distinguish it from other forces and that this differentiation is crucial. He further argues that drift is both an orientation, i.e., it tends to eliminate heterozygosity. It also has a size, which is determined by the size of the population.
Evolution by 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 grow into more complex organisms by the inherited characteristics that result from the natural activities of an organism use and misuse. Lamarckism is typically illustrated with an image of a giraffe that extends its neck to reach higher up in the trees. This causes the necks of giraffes that are longer to be passed onto their offspring who would then become 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 previous thinking on organic transformation. According to Lamarck, living things evolved from inanimate matter through a series gradual steps. Lamarck wasn't the first to propose this however he was widely thought of as the first to offer the subject a comprehensive and general explanation.
The predominant story is that Charles Darwin's theory on natural selection and Lamarckism were rivals in the 19th Century. Darwinism eventually prevailed and led to what biologists call the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead, it claims that organisms evolve through the selective influence of environmental factors, including Natural Selection.
Although Lamarck believed in the concept of inheritance by acquired characters and his contemporaries spoke of this idea but it was not an integral part of any of their evolutionary theorizing. 에볼루션 코리아 is due in part to the fact that it was never tested scientifically.
It's been over 200 years since the birth of Lamarck and in the field of genomics there is a growing evidence-based body of evidence to support the heritability acquired characteristics. This is often referred to as "neo-Lamarckism" or, more commonly, epigenetic inheritance. This is a variant that is as reliable as the popular Neodarwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is being driven by a struggle to survive. In reality, this notion is inaccurate and overlooks the other forces that are driving evolution. The fight for survival is better described as a fight to survive in a particular environment. This could be a challenge for not just other living things but also the physical surroundings themselves.
To understand how evolution functions it is important to think about what adaptation is. The term "adaptation" refers to any characteristic that allows living organisms to live in its environment and reproduce. It can be a physiological structure such as feathers or fur, or a behavioral trait such as a tendency to move into shade in hot weather or stepping out at night to avoid the cold.
The survival of an organism is dependent on its ability to draw energy from the environment and interact with other organisms and their physical environments. The organism must have the right genes to produce offspring, and must be able to access sufficient food and other resources. Moreover, the organism must be able to reproduce itself in a way that is optimally within its environment.
These factors, along with gene flow and mutation can result in a change in the proportion of alleles (different forms of a gene) in a population's gene pool. This shift in the frequency of alleles can result in the emergence of new traits, and eventually new species as time passes.
Many of the features that we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, fur or feathers to protect themselves, 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 adaptations like thick fur or gills are physical traits, while behavioral adaptations, like the desire to find companions or to move to shade in hot weather, are not. Furthermore, it is important to understand that lack of planning does not mean that something is an adaptation. Inability to think about the effects of a behavior even if it seems to be rational, may make it inflexible.