What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can lead to their development over time. This includes the appearance and development of new species.
This has been demonstrated by many examples of stickleback fish species that can live in saltwater or fresh water and walking stick insect varieties that are apprehensive about particular host plants. 무료에볼루션 , however, cannot be the reason for fundamental changes in body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all living creatures that live on our planet for many centuries. The most widely accepted explanation is that of Charles Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more effectively than those that are less well adapted. Over time, a community of well-adapted individuals increases and eventually creates a new species.
Natural selection is a process that is cyclical and involves the interaction of three factors that are: reproduction, variation and inheritance. Sexual reproduction and mutation increase the genetic diversity of a species. Inheritance is the transfer of a person's genetic traits to the offspring of that person which includes both recessive and dominant alleles. Reproduction is the process of producing fertile, viable offspring, which includes both sexual and asexual methods.
All of these variables have to be in equilibrium for natural selection to occur. For example, if an allele that is dominant at the gene can cause an organism to live and reproduce more often than the recessive one, the dominant allele will be more common in the population. But if the allele confers an unfavorable survival advantage or reduces fertility, it will be eliminated from the population. The process is self-reinforcing, meaning that a species that has a beneficial trait is more likely to survive and reproduce than an individual with an unadaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and endure, is the higher number of offspring it produces. Individuals with favorable traits, such as longer necks in giraffes or bright white patterns of color in male peacocks are more likely survive and produce offspring, and thus will become the majority of the population in the future.
Natural selection is only an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which claims that animals acquire traits by use or inactivity. If a giraffe expands its neck to reach prey and its neck gets longer, then the offspring will inherit this characteristic. 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
Genetic drift occurs when alleles from one gene are distributed randomly in a group. At some point, only one of them will be fixed (become widespread enough to not more be eliminated through natural selection) and the other alleles diminish in frequency. In extreme cases, this leads to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small group this could lead to the complete elimination of the recessive gene. This scenario is called a bottleneck effect, and it is typical of the kind of evolutionary process that occurs when a lot of individuals move to form a new population.
A phenotypic bottleneck may also occur when survivors of a disaster like an outbreak or mass hunt event are confined to a small area. The survivors will carry a dominant allele and thus will have the same phenotype. This could be caused by a conflict, earthquake or even a disease. more.. , if it is left, could be susceptible to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a deviation from the expected value due to differences in fitness. They give a famous example of twins that are genetically identical, share the exact same phenotype but one is struck by lightning and dies, while the other lives and reproduces.
This type of drift can play a very important part in the evolution of an organism. However, it is not the only way to develop. The most common alternative is to use a process known as natural selection, in which the phenotypic variation of the population is maintained through mutation and migration.
Stephens argues that there is a major difference between treating drift as a force or a cause and considering other causes of evolution such as selection, mutation and migration as causes or causes. He argues that a causal-process account of drift allows us separate it from other forces and this distinction is crucial. He also argues that drift has a direction, that is, it tends to eliminate heterozygosity, and that it also has a specific magnitude that is determined by the size of population.
Evolution through Lamarckism
Biology students in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism which means that simple organisms develop into more complex organisms taking on traits that are a product of an organism's use and disuse. Lamarckism is typically illustrated with the image of a giraffe extending its neck to reach the higher branches in the trees. This would cause giraffes to pass on their longer necks to their offspring, who would then grow even taller.
Lamarck, a French Zoologist from France, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According to him living things evolved from inanimate matter via a series of gradual steps. Lamarck was not the first to suggest that this could be the case, but the general consensus is that he was the one being the one who gave the subject his first comprehensive and comprehensive treatment.
The prevailing story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolutionary natural selection, and both theories battled out in the 19th century. Darwinism eventually won and led to the development of what biologists now refer to as the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead argues organisms evolve by the selective action of environment elements, like Natural Selection.
Although Lamarck supported the notion of inheritance by acquired characters and his contemporaries paid lip-service to this notion, it was never a central element in any of their evolutionary theories. This is partly because it was never scientifically validated.
It's been over 200 years since the birth of Lamarck, and in the age genomics, there is an increasing evidence base that supports the heritability acquired characteristics. This is often called "neo-Lamarckism" or, more frequently, epigenetic inheritance. It is a form of evolution that is just as valid as the more well-known neo-Darwinian model.
Evolution through the process of adaptation
One of the most commonly-held misconceptions about evolution is being driven by a struggle to survive. In reality, this notion is a misrepresentation of natural selection and ignores the other forces that drive evolution. The struggle for survival is more accurately described as a struggle to survive within a particular environment, which may involve not only other organisms but as well the physical environment.
Understanding how adaptation works is essential to comprehend evolution. The term "adaptation" refers to any specific feature that allows an organism to live and reproduce in its environment. It can be a physiological feature, like feathers or fur, or a behavioral trait like moving into shade in hot weather or coming out at night to avoid the cold.
The survival of an organism depends on its ability to obtain energy from the environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes to create offspring, and be able to find sufficient food and resources. The organism must also be able to reproduce itself at a rate that is optimal for its specific niche.
These factors, along with mutation and gene flow, lead to a change in the proportion of alleles (different types of a 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 about animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, feathers or fur for insulation and long legs for running away from predators and camouflage to hide. To comprehend adaptation it is essential to distinguish between behavioral and physiological characteristics.
Physiological adaptations, such as the 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, aren't. It is also important to keep in mind that the absence of planning doesn't make an adaptation. In fact, failing to consider the consequences of a choice can render it unadaptable, despite the fact that it may appear to be logical or even necessary.