What is Free Evolution?
Free evolution is the concept that natural processes can lead to the development of organisms over time. This includes the appearance and development of new species.
Numerous examples have been offered of this, such as different kinds of stickleback fish that can live in salt or fresh water, as well as walking stick insect varieties that are attracted to particular host plants. These mostly reversible traits permutations cannot explain fundamental changes to the body's basic plans.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all the living organisms that inhabit our planet for ages. Charles Darwin's natural selection is the best-established explanation. This is because individuals who are better-adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, the number of well-adapted individuals becomes larger and eventually develops into an entirely new species.
Natural selection is an ongoing process and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity within the species. Inheritance is the term used to describe the transmission of a person's genetic characteristics, which includes recessive and dominant genes and their offspring. Reproduction is the production of viable, fertile offspring, which includes both sexual and asexual methods.
에볼루션 of these variables have to be in equilibrium to allow natural selection to take place. For instance when a dominant allele at the gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will become more prevalent within the population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will disappear. The process is self-reinforcing, meaning that an organism with a beneficial trait will survive and reproduce more than one with an unadaptive trait. The higher the level of fitness an organism has which is measured by its ability to reproduce and survive, is the greater number of offspring it can produce. Individuals with favorable characteristics, such as a long neck in giraffes, or bright white patterns on male peacocks are more likely than others to survive and reproduce, which will eventually lead to them becoming the majority.
Natural selection only acts on populations, not individuals. This is a significant distinction from the Lamarckian theory of evolution, which states that animals acquire traits by use or inactivity. If a giraffe stretches its neck to catch prey and its neck gets longer, then its children will inherit this characteristic. The difference in neck length between generations will persist until the giraffe's neck gets so long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles of a gene could attain different frequencies in a group due to random events. Eventually, only one will be fixed (become common enough that it can no more be eliminated through natural selection), and the rest of the alleles will diminish in frequency. In the extreme this, it leads to a single allele dominance. The other alleles are eliminated, and heterozygosity decreases 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 evolutionary process when a lot of people migrate to form a new group.
A phenotypic bottleneck may also occur when the survivors of a catastrophe like an outbreak or a mass hunting event 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 can be caused by war, earthquakes or even plagues. Whatever the reason the genetically distinct population that remains is prone 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 and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift can be vital to the evolution of the species. This isn't the only method for evolution. The most common alternative is to use a process known as natural selection, where the phenotypic diversity of the population is maintained through mutation and migration.
Stephens argues there is a significant difference between treating the phenomenon of drift as an actual cause or force, and considering other causes, such as migration and selection mutation as forces and causes. He argues that a causal-process explanation of drift lets us separate it from other forces and that this differentiation is crucial. He also claims that drift has a direction, that is it tends to reduce heterozygosity. It also has a size, that is determined by population size.
Evolution by 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”, states that simple organisms develop into more complex organisms by adopting traits that result from the use and abuse of an organism. Lamarckism is typically illustrated with the image of a giraffe that extends its neck further to reach higher up in the trees. 에볼루션코리아 could cause giraffes to pass on their longer necks to offspring, who then become taller.
Lamarck was a French Zoologist. In his opening lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on 17 May 1802, he introduced a groundbreaking concept that radically challenged the conventional wisdom about organic transformation. In his view, living things had evolved from inanimate matter via a series of gradual steps. Lamarck was not the only one to suggest that this could be the case but he is widely seen as being the one who gave the subject its first general and thorough treatment.
The dominant story is that Charles Darwin's theory of natural selection and Lamarckism fought in the 19th century. Darwinism eventually won and led to the creation of what biologists now refer to as the Modern Synthesis. The Modern Synthesis theory denies the possibility that acquired traits can be acquired through inheritance and instead, it argues that organisms develop through the selective action of environmental factors, including natural selection.
Although Lamarck supported the notion of inheritance by acquired characters, and his contemporaries also offered a few words about this idea but it was not an integral part of any of their evolutionary theories. This is due to the fact that it was never scientifically validated.
It has been more than 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 of acquired traits. This is referred to as "neo Lamarckism", or more generally epigenetic inheritance. This is a version that is just as valid as the popular neodarwinian model.
similar site through Adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle for survival. This view is inaccurate and overlooks the other forces that drive evolution. The struggle for existence is more accurately described as a struggle to survive in a particular environment. This can include not only other organisms, but also the physical environment.
Understanding adaptation is important to comprehend evolution. It refers to a specific characteristic that allows an organism to live and reproduce within its environment. It can be a physiological feature, like feathers or fur, or a behavioral trait such as a tendency to move into the shade in hot weather or stepping out at night to avoid the cold.
The ability of a living thing to extract energy from its surroundings and interact with other organisms and their physical environments, is crucial to its survival. The organism must possess the right genes to create offspring, and it must be able to locate sufficient food and other resources. The organism must also be able to reproduce itself at the rate that is suitable for its specific niche.
These factors, together with gene flow and mutation can result in a change in the proportion of alleles (different forms of a gene) in the population's gene pool. The change in frequency of alleles can result in the emergence of novel traits and eventually new species over time.
Many of the features we admire in animals and plants are adaptations. For instance lung or gills that draw oxygen from air, fur and feathers as insulation long legs to run away from predators and camouflage for hiding. To understand the concept of adaptation it is essential to differentiate between physiological and behavioral traits.
Physiological adaptations, like thick fur or gills are physical traits, while behavioral adaptations, like the tendency to search for companions or to move into the shade in hot weather, are not. Additionally, it is important to note that a lack of thought is not a reason to make something an adaptation. A failure to consider the consequences of a decision even if it seems to be rational, could cause it to be unadaptive.