What is Free Evolution?
Free evolution is the idea that the natural processes of living organisms can cause them to develop over time. This includes the emergence and development of new species.
Numerous examples have been offered of this, such as different kinds of stickleback fish that can be found in fresh or salt water and walking stick insect varieties that prefer particular host plants. These mostly reversible traits permutations are not able to explain fundamental changes to the basic body plan.
Evolution through Natural Selection
The development of the myriad living creatures on Earth is a mystery that has intrigued scientists for many centuries. The most well-known explanation is Charles Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those less well adapted. Over time, a community of well-adapted individuals expands and eventually forms a whole new species.
Natural selection is a process that is cyclical and involves the interaction of three factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within an animal species. Inheritance refers to the passing of a person's genetic characteristics to his or her offspring which includes both recessive and dominant alleles. Reproduction is the production of fertile, viable offspring, which includes both sexual and asexual methods.
Natural selection can only occur when all the factors are in equilibrium. If, for example, a dominant gene allele causes an organism reproduce and live longer than the recessive gene, then the dominant allele becomes more prevalent in a population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will disappear. This process is self-reinforcing, which means that an organism that has an adaptive trait will survive and reproduce much more than those with a maladaptive feature. The greater an organism's fitness, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with good traits, like a longer neck in giraffes, or bright white colors in male peacocks are more likely survive and produce offspring, and thus will make up the majority of the population in the future.
Natural selection only affects populations, not on individuals. This is an important distinction from the Lamarckian theory of evolution which claims that animals acquire traits by use or inactivity. For instance, if the giraffe's neck gets longer through reaching out to catch prey, its offspring will inherit a more long neck. The differences in neck length between generations will persist until the giraffe's neck becomes too long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when the alleles of one gene are distributed randomly in a group. In the end, only one will be fixed (become common enough to no longer be eliminated by natural selection), and the other alleles will diminish in frequency. In the extreme this, it leads to one allele dominance. The other alleles have been essentially eliminated and heterozygosity has decreased to zero. In a small number of people, this could result in the complete elimination of recessive gene. This is called a bottleneck effect, and it is typical of evolutionary process that occurs when a large number of individuals migrate to form a new population.
A phenotypic 'bottleneck' can also occur when survivors of a disaster like an outbreak or mass hunting event are confined to a small area. The survivors will be mostly homozygous for the dominant allele, which means they will all share the same phenotype and consequently share the same fitness characteristics. This could be caused by war, earthquakes or even plagues. Regardless of the cause the genetically distinct population that remains is prone to genetic drift.
Walsh Lewens and Ariew use Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values of differences in fitness. They provide a well-known instance of twins who are genetically identical, share identical phenotypes but one is struck by lightning and 무료에볼루션 (evolutionkr.kr) dies, while the other lives and reproduces.
This type of drift is crucial in the evolution of the species. But, it's not the only way to evolve. Natural selection is the main alternative, where mutations and migration maintain the phenotypic diversity of the population.
Stephens asserts that there is a huge difference between treating the phenomenon of drift as a force or cause, and treating other causes like migration and selection mutation as forces and causes. He claims that a causal-process account of drift allows us differentiate it from other forces and that this distinction is crucial. He further argues that drift has a direction, that is it tends to reduce heterozygosity, and that it also has a magnitude, that is determined by population size.
Evolution by Lamarckism
When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as "Lamarckism is based on the idea that simple organisms develop into more complex organisms through inheriting characteristics that result from the use and abuse of an organism. Lamarckism is illustrated through the giraffe's neck being extended to reach higher levels of leaves in the trees. This could cause giraffes to give their longer necks to offspring, who would then grow even taller.
Lamarck Lamarck, a 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 the previous thinking on organic transformation. In his view living things evolved from inanimate matter through a series of gradual steps. Lamarck wasn't the only one to suggest this however he was widely considered to be the first to provide the subject a comprehensive and general explanation.
The most popular story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were competing in the 19th Century. Darwinism ultimately prevailed which led to what biologists refer to as the Modern Synthesis. The theory argues that traits acquired through evolution can be inherited and instead, it argues that organisms develop through the selective action of environmental factors, including natural selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed down to future generations. However, this notion was never a central part of any of their evolutionary theories. This is due in part to the fact that it was never tested scientifically.
It's been more than 200 year since Lamarck's birth and in the field of age genomics, there is a growing evidence base that supports the heritability of acquired traits. This is also known as "neo Lamarckism", or more often epigenetic inheritance. It is a version of evolution that is as valid as the more well-known Neo-Darwinian model.
Evolution by adaptation
One of the most common misconceptions about evolution is that it is driven by a sort of struggle for survival. This notion is not true and ignores other forces driving evolution. The fight for survival can be more precisely described as a fight to survive within a specific environment, which could include not just other organisms, but as well the physical environment.
Understanding adaptation is important to understand evolution. It is a feature that allows a living organism to live in its environment and reproduce. It can be a physical feature, such as feathers or fur. Or it can be a behavior trait that allows you to move to the shade during hot weather or moving out to avoid the cold at night.
An organism's survival depends on its ability to extract energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism must have the right genes to create offspring, and must be able to find enough food and other resources. The organism must also be able to reproduce itself at an amount that is appropriate for its particular niche.
These elements, along with gene flow and mutations can result in an alteration in the ratio of different alleles within a population’s gene pool. This shift in the frequency of alleles could lead to the development of novel traits and eventually, new species as time passes.
Many of the characteristics we appreciate in animals and plants are adaptations. For instance the lungs or gills which extract oxygen from the air feathers and fur as insulation, long legs to run away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires attention to the distinction between behavioral and physiological characteristics.
Physiological traits like large gills and thick fur are physical traits. The behavioral adaptations aren't an exception, for instance, the tendency of animals to seek companionship or retreat into shade in hot weather. Additionally, it is important to note that lack of planning does not make something an adaptation. Inability to think about the implications of a choice, even if it appears to be logical, can make it unadaptive.