What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can lead to their development over time. This includes the appearance and development of new species.
This is evident in many examples, including stickleback fish varieties that can thrive in salt or fresh water, and walking stick insect varieties that have a preference for specific host plants. These mostly reversible trait permutations, however, cannot explain fundamental changes in basic body plans.
Evolution through Natural Selection
The evolution of the myriad living organisms on Earth is a mystery that has intrigued scientists for decades. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when people who are more well-adapted have more success in reproduction and survival than those who are less well-adapted. As 에볼루션 무료체험 , the number of well-adapted individuals becomes larger and eventually creates a new species.
Natural selection is an ongoing process that involves the interaction of three elements including inheritance, variation, and reproduction. Mutation and sexual reproduction increase genetic diversity in the species. Inheritance refers to the transmission of genetic characteristics, which includes recessive and dominant genes to their offspring. Reproduction is the production of fertile, viable offspring which includes both sexual and asexual methods.
All of these variables must be in balance to allow natural selection to take place. If, for instance the dominant gene allele causes an organism reproduce and survive more than the recessive gene The dominant allele is more prevalent in a group. However, if the allele confers a disadvantage in survival or decreases fertility, it will be eliminated from the population. The process is self-reinforcing, meaning that a species with a beneficial trait will survive and reproduce more than one with a maladaptive characteristic. Info which is measured by its ability to reproduce and survive, is the more offspring it can produce. People with good characteristics, like a longer neck in giraffes and bright white colors in male peacocks are more likely survive and have offspring, which means they will become the majority of the population in the future.
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 characteristics by use or inactivity. If a giraffe extends its neck in order to catch prey, and the neck becomes longer, then its offspring will inherit this trait. The difference in neck length between generations will continue until the neck of the giraffe becomes too long that it can not breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed within a population. Eventually, only one will be fixed (become widespread enough to not longer be eliminated by natural selection), and the rest of the alleles will decrease in frequency. In extreme cases, this leads to a single allele dominance. Other alleles have been essentially eliminated and heterozygosity has been reduced to a minimum. In a small group, this could lead to the total elimination of the recessive allele. This is known as the bottleneck effect. It is typical of the evolution process that occurs when a large number individuals migrate to form a group.
A phenotypic bottleneck may also occur when the survivors of a disaster like an outbreak or a mass hunting incident are concentrated in the same area. The survivors are likely to be homozygous for the dominant allele, meaning that they all have the same phenotype, and consequently have the same fitness traits. This situation could be caused by earthquakes, war or even plagues. Whatever the reason, the genetically distinct population that is left might be susceptible to genetic drift.
Walsh Lewens and Ariew utilize a "purely outcome-oriented" definition of drift as any departure from the expected values of different fitness levels. 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 lives to reproduce.
This kind of drift can play a significant role in the evolution of an organism. However, it's not the only way to evolve. The primary alternative is a process called natural selection, in which the phenotypic variation of an individual is maintained through mutation and migration.
Stephens claims that there is a huge difference between treating the phenomenon of drift as an agent or cause and considering other causes, such as migration and selection mutation as causes and forces. He argues that a causal process explanation of drift allows us to distinguish it from these other forces, and that this distinction is crucial. He also argues that drift has a direction, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by the size of the population.
Evolution through Lamarckism
Biology students in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. 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 disuse. Lamarckism is typically illustrated by the image of a giraffe that extends its neck further to reach leaves higher up in the trees. This process would cause giraffes to give their longer necks to their offspring, who then grow even taller.
Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th May 1802, he introduced an original idea that fundamentally challenged the conventional wisdom about organic transformation. According to him, living things had evolved from inanimate matter through a series of gradual steps. Lamarck was not the first to suggest that this could be the case, but he is widely seen as being the one who gave the subject its first broad and comprehensive treatment.
The popular narrative is that Lamarckism grew into a rival to Charles Darwin's theory of evolution by natural selection and that the two theories battled each other in the 19th century. Darwinism eventually won and led to the development of what biologists today refer to as the Modern Synthesis. The Modern Synthesis theory denies that acquired characteristics can be inherited and instead suggests that organisms evolve through the selective action of environmental factors, like natural selection.
Although 에볼루션코리아 endorsed the idea of inheritance through acquired characters, and his contemporaries also spoke of this idea but it was not a major feature in any of their evolutionary theories. This is partly because it was never scientifically validated.
It has been more than 200 year since Lamarck's birth, and in the age genomics, there is an increasing evidence-based body of evidence to support the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more often epigenetic inheritance. This is a version that is just as valid as the popular Neodarwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is its being driven by a fight for survival. This view is inaccurate and ignores other forces driving evolution. The fight for survival is more accurately described as a struggle to survive in a specific environment. This may include not just other organisms but also the physical surroundings themselves.
To understand how evolution works, it is helpful to think about what adaptation is. It is a feature that allows living organisms to live in its environment and reproduce. It can be a physiological feature, like feathers or fur or a behavioral characteristic, such as moving into shade in the heat or leaving at night to avoid cold.
The ability of an organism to draw energy from its environment and interact with other organisms as well as their physical environment, is crucial to its survival. The organism must possess the right genes to produce offspring, and it must be able to locate enough food and other resources. Furthermore, the organism needs to be able to reproduce itself in a way that is optimally within its niche.
These elements, in conjunction with gene flow and mutation can result in changes in the ratio of alleles (different types of a gene) in the gene pool of a population. The change in frequency of alleles can result in the emergence of new traits and eventually new species over time.
Many of the characteristics we admire about animals and plants are adaptations, for example, lung or gills for removing oxygen from the air, fur or feathers to protect themselves long legs to run away from predators and camouflage to hide. However, a proper understanding of adaptation requires a keen eye to the distinction between physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills, are physical traits, while behavioral adaptations, such as the tendency to search for companions or to move to shade in hot weather, are not. Furthermore, it is important to note that a lack of thought does not mean that something is an adaptation. Inability to think about the implications of a choice even if it appears to be logical, can make it inflexible.