What is Free Evolution?
Free evolution is the concept that natural processes can lead to the development of organisms over time. This includes the evolution of new species and the transformation of the appearance of existing species.
This has been proven by numerous examples such as the stickleback fish species that can thrive in saltwater or fresh water and walking stick insect species that have a preference for particular host plants. These reversible traits however, are not able to explain fundamental changes in basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all the living organisms that inhabit our planet for centuries. Charles Darwin's natural selectivity is the best-established explanation. This process occurs when those who are better adapted have more success in reproduction and survival than those who are less well-adapted. Over time, the population of individuals who are well-adapted grows and eventually develops into a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity of a species. Inheritance refers the transmission of genetic traits, including both dominant and recessive genes and their offspring. Reproduction is the process of producing viable, fertile offspring. This can be achieved via sexual or asexual methods.
Natural selection is only possible when all of these factors are in harmony. If, for instance, a dominant gene allele allows an organism to reproduce and last longer than the recessive gene allele The dominant allele will become more common in a population. However, if the gene confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. This process is self-reinforcing which means that an organism with a beneficial characteristic is more likely to survive and reproduce than one with a maladaptive characteristic. The more offspring that an organism has the more fit it is, which is measured by its capacity to reproduce and survive. People with good characteristics, like having a longer neck in giraffes, or bright white colors in male peacocks, are more likely to survive and have offspring, and thus will make up the majority of the population over time.
Natural selection only acts on populations, not individual organisms. This is an important distinction from the Lamarckian theory of evolution which argues that animals acquire traits by use or inactivity. If a giraffe expands its neck to catch prey, and the neck becomes longer, then the children will inherit this characteristic. The differences in neck size between generations will continue to grow until the giraffe is no longer able to reproduce with other giraffes.
무료에볼루션 by Genetic Drift
Genetic drift occurs when the alleles of one gene are distributed randomly within a population. Eventually, one of them will attain fixation (become so widespread that it can no longer be eliminated through natural selection), while the other alleles drop to lower frequencies. In the extreme it can lead to one allele dominance. Other alleles have been basically eliminated and heterozygosity has diminished to zero. In a small group, this could lead to the total elimination of the recessive allele. This scenario is known as a bottleneck effect and it is typical of evolutionary process when a large number of individuals migrate to form a new population.
A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or a mass hunting incident are concentrated in a small area. The survivors will have an allele that is dominant and will have the same phenotype. This could be caused by a conflict, earthquake, or even a plague. The genetically distinct population, if it remains susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected value due to differences in fitness. They cite the famous example of twins who are both genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, but the other lives to reproduce.
This kind of drift can play a crucial part in the evolution of an organism. It's not the only method for evolution. The most common alternative is a process called natural selection, in which the phenotypic variation of the population is maintained through mutation and migration.
Stephens argues there is a significant difference between treating drift like an actual cause or force, and treating other causes such as migration and selection mutation as forces and causes. He claims that a causal process account of drift permits us to differentiate it from the other forces, and that this distinction is vital. He further argues that drift has both a direction, i.e., it tends to reduce heterozygosity. It also has a size, which is determined by population size.
Evolution by Lamarckism
In high school, students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, often called "Lamarckism, states that simple organisms transform into more complex organisms adopting traits that are a product of an organism's use and disuse. Lamarckism is typically illustrated with a picture of a giraffe stretching its neck further to reach the higher branches in the trees. This causes giraffes' longer necks to be passed onto their offspring who would grow taller.
Lamarck the French Zoologist, introduced an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to Lamarck, living creatures evolved from inanimate matter by a series of gradual steps. Lamarck was not the only one to suggest that this might be the case but the general consensus is that he was the one having given the subject its first general and comprehensive treatment.
The most popular story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were rivals during the 19th century. Darwinism eventually triumphed, leading to the development of what biologists today refer to as the Modern Synthesis. The theory denies that acquired characteristics can be passed down through generations and instead, it claims that organisms evolve through the influence of environment factors, including Natural Selection.
While Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries offered a few words about this idea, it was never an integral part of any of their theories about evolution. This is partly due to the fact that it was never validated scientifically.
It's been more than 200 years since the birth of Lamarck, and in the age genomics, there is an increasing evidence base that supports the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model.
Evolution by Adaptation
One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. This is a false assumption and overlooks other forces that drive evolution. The fight for survival is better described as a struggle to survive in a certain environment. This may include not just other organisms, but also the physical environment.
Understanding the concept of adaptation is crucial to comprehend evolution. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce within its environment. It can be a physical feature, such as feathers or fur. Or it can be a trait of behavior, like moving to the shade during hot weather, or escaping the cold at night.
The ability of an organism to extract 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 create offspring, and be able to find sufficient food and resources. 에볼루션사이트 should be able to reproduce itself at a rate that is optimal for its niche.
These factors, together with gene flow and mutations can cause changes in the proportion of different alleles within the gene pool of a population. This change in allele frequency can lead to the emergence of new traits, and eventually new species in the course of time.
A lot of the traits we admire about animals and plants are adaptations, such as lungs or gills to extract oxygen from the air, feathers or fur to protect themselves long legs to run away from predators, and camouflage to hide. To understand the concept of adaptation, it is important to discern between physiological and behavioral traits.
Physiological adaptations, like the thick fur or gills are physical traits, while behavioral adaptations, like the tendency to search for friends or to move into the shade in hot weather, aren't. It is important to remember that a insufficient planning does not result in an adaptation. Failure to consider the implications of a choice, even if it appears to be rational, may make it unadaptive.