Why All The Fuss Over Free Evolution?
What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can lead them to evolve over time. This includes the development of new species and the transformation of the appearance of existing species.
This has been proven by many examples, including stickleback fish varieties that can live in saltwater or fresh water and walking stick insect varieties that are apprehensive about specific host plants. These mostly reversible trait permutations can't, however, 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 ages. Charles Darwin's natural selection theory is the most well-known explanation. This is because those who are better adapted survive and reproduce more than those who are less well-adapted. As time passes, a group of well-adapted individuals expands and eventually creates a new species.
Natural selection is a cyclical process that involves the interaction of three elements that are inheritance, variation and reproduction. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity within an animal species. Inheritance is the transfer of a person's genetic characteristics to the offspring of that person which includes both dominant and recessive alleles. Reproduction is the production of viable, fertile offspring, which includes both asexual and sexual methods.
All of these elements must be in harmony for natural selection to occur. If, for example the dominant gene allele makes an organism reproduce and last longer than the recessive gene, then the dominant allele will become more common in a population. If the allele confers a negative advantage to survival or reduces the fertility of the population, it will go away. The process is self-reinforced, meaning that a species with a beneficial characteristic will survive and reproduce more than an individual with an unadaptive characteristic. The more offspring an organism can produce the more fit it is, which is measured by its capacity to reproduce and survive. People with desirable traits, like having a long neck in Giraffes, or the bright white patterns on male peacocks, are more likely than others to live and reproduce, which will eventually lead to them becoming the majority.
Natural selection is only an aspect of populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution which holds that animals acquire traits due to use or lack of use. If a giraffe expands its neck to reach prey and the neck grows longer, then the offspring will inherit this trait. The difference in neck length between generations will continue until the giraffe's neck gets too long to no longer breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from one gene are distributed randomly in a group. Eventually, only one will be fixed (become widespread enough to not more be eliminated through natural selection) and the other alleles diminish in frequency. This can lead to an allele that is dominant at the extreme. The other alleles are virtually eliminated and heterozygosity diminished to a minimum. In a small group it could result in the complete elimination of recessive gene. Such a scenario would be known as a bottleneck effect and it is typical of evolutionary process when a lot of individuals move to form a new population.
에볼루션 바카라 무료체험 can also occur when the survivors of a catastrophe such as an outbreak or mass hunting event are concentrated in the same area. The survivors will share an allele that is dominant and will have the same phenotype. This may be caused by a conflict, earthquake or even a cholera outbreak. Whatever the reason, the genetically distinct population that remains is susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a deviation from the expected values due to differences in fitness. They cite the famous example of twins that are genetically identical and share the same phenotype, but one is struck by lightning and dies, whereas the other is able to reproduce.
This kind of drift can play a very important role in the evolution of an organism. But, it's not the only method to progress. Natural selection is the most common alternative, in which mutations and migration maintain the phenotypic diversity of a population.
Stephens argues there is a huge distinction between treating 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 model of drift allows us to separate it from other forces and that this differentiation is crucial. He further argues that drift has a direction, that is it tends to reduce heterozygosity, and that it also has a size, that is determined by the size of the population.
Evolution through Lamarckism
When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, often called "Lamarckism, states that simple organisms evolve into more complex organisms adopting traits that result from the organism's use and misuse. Lamarckism is illustrated through a giraffe extending its neck to reach higher leaves in the trees. This would cause giraffes to give their longer necks to their offspring, which then get taller.
Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate zoology at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced an original idea that fundamentally challenged previous thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate matter by a series of gradual steps. Lamarck was not the first to make this claim but he was regarded as the first to give the subject a thorough and general overview.
The dominant story is that Charles Darwin's theory of natural selection and Lamarckism were competing during the 19th century. Darwinism eventually prevailed, leading to what biologists call the Modern Synthesis. The theory argues that acquired characteristics can be inherited, and instead argues that organisms evolve through the selective action of environmental factors, like natural selection.
While Lamarck supported the notion of inheritance by acquired characters and his contemporaries also offered a few words about this idea however, it was not a central element in any of their evolutionary theories. This is due in part to the fact that it was never validated scientifically.
It's been more than 200 years since Lamarck was born and in the age of genomics there is a huge amount of evidence to support the heritability of acquired traits. This is also known as "neo Lamarckism", or more often epigenetic inheritance. This is a model that is as reliable as the popular neodarwinian model.
Evolution through the process of adaptation
One of the most popular misconceptions about evolution is being driven by a struggle for survival. This notion is not true and overlooks other forces that drive evolution. The fight for survival can be more precisely described as a fight to survive within a particular environment, which could include not just other organisms, but also the physical environment.
To understand how evolution works, it is helpful to think about what adaptation is. Adaptation is any feature that allows living organisms to live in its environment and reproduce. It could be a physical structure like fur or feathers. Or it can be a characteristic of behavior, like moving towards shade during hot weather, or escaping the cold at night.
The survival of an organism depends on its ability to obtain energy from the environment and to interact with other living organisms and their physical surroundings. The organism needs to have the right genes to create offspring, and it should be able to find enough food and other resources. The organism should also be able to reproduce itself at a rate that is optimal for its specific niche.
These factors, together with gene flow and mutations can cause an alteration in the ratio of different alleles within a population’s gene pool. This shift in the frequency of alleles can lead to the emergence of novel traits and eventually, new species in the course of time.
Many of the features that we admire in animals and plants are adaptations, like 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 understand adaptation, it is important to discern between physiological and behavioral traits.
Physical traits such as large gills and thick fur are physical traits. Behavior adaptations aren't an exception, for instance, the tendency of animals to seek out companionship or to retreat into the shade during hot weather. Furthermore it is important to note that lack of planning 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, may cause it to be unadaptive.