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.
A variety of examples have been provided of this, such as different varieties of stickleback fish that can live in either fresh or salt water and walking stick insect varieties that are attracted to particular host plants. These reversible traits do not explain the fundamental changes in the body's basic plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is an enigma that has fascinated scientists for centuries. 에볼루션 바카라 사이트 -known explanation is that of Charles Darwin's natural selection process, a process that is triggered when more well-adapted individuals live longer and reproduce more successfully than those who are less well adapted. As time passes, the number of well-adapted individuals becomes larger and eventually creates an entirely new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity within the species. Inheritance refers the transmission of a person’s genetic traits, which include recessive and dominant genes to their offspring. Read More Listed here is the production of fertile, viable offspring which includes both sexual and asexual methods.
Natural selection only occurs when all of these factors are in harmony. For example when an allele that is dominant at one gene can cause an organism to live and reproduce more frequently than the recessive one, the dominant allele will be more prominent within the population. However, if the allele confers an unfavorable survival advantage or decreases fertility, it will disappear from the population. The process is self-reinforcing, which means that an organism with a beneficial trait can reproduce and survive longer than an individual with a maladaptive trait. The greater an organism's fitness which is measured by its ability to reproduce and survive, is the greater number of offspring it produces. People with good characteristics, like having a longer neck in giraffes, or bright white color patterns in male peacocks are more likely be able to survive and create offspring, which means they will make up the majority of the population over time.
Natural selection is an aspect of populations and not on individuals. This is a crucial distinction from the Lamarckian theory of evolution which holds that animals acquire traits due to the use or absence of use. For example, if a giraffe's neck gets longer through reaching out to catch prey and its offspring will inherit a longer neck. The differences in neck length between generations will persist until the giraffe's neck becomes too long to no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when the alleles of 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 rest of the alleles will decrease in frequency. This could lead to an allele that is dominant in the extreme. The other alleles are eliminated, and heterozygosity decreases to zero. In a small number of people it could lead to the total elimination of the recessive allele. This scenario is called the bottleneck effect. It is typical of the evolution process that occurs when an enormous number of individuals move to form a group.
A phenotypic bottleneck can also occur when survivors of a disaster like an outbreak or mass hunting event are concentrated in an area of a limited size. The surviving individuals are likely to be homozygous for the dominant allele which means they will all share the same phenotype and will therefore have the same fitness traits. This situation could be caused by earthquakes, war or even plagues. The genetically distinct population, if it is left susceptible to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a deviation from the expected value due to differences in fitness. They cite a famous example of twins that are genetically identical and have identical phenotypes, and yet one is struck by lightning and dies, whereas the other lives and reproduces.
This type of drift is crucial in the evolution of an entire species. It is not the only method of evolution. Natural selection is the most common alternative, in which mutations and migration keep the phenotypic diversity in the population.
Stephens asserts that there is a vast distinction between treating drift as an actual cause or force, and considering 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 this distinction is essential. He also claims that drift is a directional force: that is it tends to reduce heterozygosity. It also has a magnitude, which is determined by the size of population.
Evolution through Lamarckism
When students in high school study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is generally referred to as "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of traits that result from the organism's natural actions, use and disuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher branches in the trees. This could cause the longer necks of giraffes to be passed onto their offspring who would then grow even taller.
Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th May 1802, he introduced an innovative concept that completely challenged previous thinking about organic transformation. According to him living things evolved from inanimate matter through an escalating series of steps. Lamarck was not the first to suggest that this might be the case but the general consensus is that he was the one having given the subject his first comprehensive and comprehensive treatment.
The most popular story is that Lamarckism grew into a rival to Charles Darwin's theory of evolutionary natural selection and both theories battled it out in the 19th century. Darwinism ultimately prevailed, leading to what biologists call the Modern Synthesis. The Modern Synthesis theory denies the possibility that acquired traits can be inherited and instead, it argues that organisms develop through the action of environmental factors, including natural selection.
Although Lamarck supported the notion of inheritance by acquired characters and his contemporaries also paid lip-service to this notion, it was never a major feature in any of their evolutionary theories. This is largely due to the fact that it was never validated scientifically.
It's been over 200 year since Lamarck's birth, and in the age genomics there is a growing body of evidence that supports the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more often epigenetic inheritance. This is a version 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 fight for survival. This notion is not true and ignores other forces driving evolution. The fight for survival is better described as a fight to survive in a specific environment. This could include not only other organisms as well as the physical surroundings themselves.
Understanding how adaptation works is essential to comprehend evolution. 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 characteristic such as a tendency to move into shade in the heat or leaving at night to avoid cold.
An organism's survival depends on its ability to extract energy from the environment and interact with other organisms and their physical environments. The organism should possess the right genes for producing offspring and be able find sufficient food and resources. Furthermore, the organism needs to be able to reproduce itself at an optimal rate within its environmental niche.
These elements, along with gene flow and mutations can result in changes in the proportion of different alleles within the population's gene pool. This shift in the frequency of alleles can result in the emergence of new traits and eventually, new species in the course of time.
A lot of the traits we find appealing in plants and animals are adaptations. For instance lung or gills that extract oxygen from the air, fur and feathers as insulation and long legs to get away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires attention to the distinction between the physiological and behavioral traits.
Physiological adaptations, like the thick fur or gills are physical traits, while behavioral adaptations, like the tendency to search for companions or to move to shade in hot weather, are not. It is also important to note that insufficient planning does not result in an adaptation. Inability to think about the effects of a behavior, even if it appears to be rational, may make it unadaptive.