What is Free Evolution?
Free evolution is the notion that natural processes can lead to the development of organisms over time. This includes the development of new species and the alteration of the appearance of existing species.
This has been proven by many examples such as the stickleback fish species that can be found in salt or fresh water, and walking stick insect types that are apprehensive about particular host plants. These reversible traits can't, however, explain fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad living organisms on Earth is an enigma that has fascinated scientists for decades. The most widely accepted explanation is Charles Darwin's natural selection, which is triggered when more well-adapted individuals live longer and reproduce more effectively than those who are less well adapted. As time passes, the number of well-adapted individuals grows and eventually forms an entirely new species.
Natural selection is a cyclical process that involves the interaction of three elements including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within a species. Inheritance is the transfer of a person's genetic traits to the offspring of that person which includes both recessive and dominant alleles. Reproduction is the process of producing viable, fertile offspring. This can be accomplished by both asexual or sexual methods.
All of these factors have to be in equilibrium to allow natural selection to take place. If, for example the dominant gene allele causes an organism reproduce and live longer than the recessive gene allele then the dominant allele will become more common in a population. However, if the gene confers a disadvantage in survival or reduces fertility, it will disappear from the population. The process is self reinforcing meaning that an organism with an adaptive characteristic will live and reproduce more quickly than those with a maladaptive trait. The more offspring that an organism has, the greater its fitness that is determined by its capacity to reproduce itself and survive. People with desirable traits, such as 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 in the future.
Natural selection is only a factor in populations and not on individuals. 무료에볼루션 is a significant distinction from the Lamarckian theory of evolution which claims that animals acquire characteristics through use or neglect. For instance, if a giraffe's neck gets longer through reaching out to catch prey and its offspring will inherit a more long neck. The difference in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles at a gene may reach different frequencies in a population by chance events. In the end, one will attain fixation (become so common that it is unable to be removed through natural selection) and other alleles fall to lower frequencies. This can lead to an allele that is dominant in the extreme. The other alleles are basically eliminated and heterozygosity has been reduced to zero. In a small number of people it could result in the complete elimination of the recessive gene. This scenario is called the bottleneck effect and is typical of an evolutionary process that occurs whenever the number of individuals migrate to form a population.
A phenotypic bottleneck could occur when survivors of a disaster such as an epidemic or a mass hunting event, are concentrated in a limited area. The surviving individuals are likely to be homozygous for the dominant allele, which means they will all share the same phenotype and thus share the same fitness characteristics. This could be caused by war, earthquakes or even plagues. The genetically distinct population, if it is left, could be susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from expected values for different fitness levels. They cite the famous example of twins that are genetically identical and share the same phenotype. However, one is struck by lightning and dies, whereas the other continues to reproduce.
This type of drift is very important in the evolution of an entire species. But, it's not the only method to evolve. 무료 에볼루션 is the most common alternative, in which mutations and migrations maintain the phenotypic diversity in a population.
Stephens asserts that there is a significant difference between treating the phenomenon of drift as a force, or an underlying cause, and treating other causes of evolution such as selection, mutation and migration as forces or causes. Stephens claims that a causal process model of drift allows us to differentiate it from other forces, and this distinction is crucial. He also argues that drift has an orientation, i.e., it tends to reduce heterozygosity. It also has a size, which is determined based on 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, also referred to as "Lamarckism is based on the idea that simple organisms develop into more complex organisms through inheriting characteristics that result from an organism's use and disuse. Lamarckism is typically illustrated with the image of a giraffe extending its neck further to reach the higher branches in the trees. This could cause the longer necks of giraffes to be passed on to their offspring who would then become taller.
Lamarck was a French Zoologist. In his lecture to begin his course on invertebrate zoology held at the Museum of Natural History in Paris on 17 May 1802, he introduced an original idea that fundamentally challenged the conventional wisdom about organic transformation. According Lamarck, living organisms evolved from inanimate matter through a series gradual steps. Lamarck was not the only one to suggest that this might be the case but his reputation is widely regarded as having given the subject its first general and thorough treatment.
The most popular story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection, and that the two theories fought it out in the 19th century. Darwinism eventually prevailed, leading to the development of what biologists now refer to as the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead argues that organisms evolve through the selective action of environment factors, such as Natural Selection.
Although Lamarck endorsed the idea of inheritance through acquired characters, and his contemporaries also spoke of this idea, it was never a central element in any of their evolutionary theories. This is partly because it was never scientifically tested.
It's been more than 200 year since Lamarck's birth and in the field of genomics, there is a growing body of evidence that supports the heritability acquired characteristics. It is sometimes called "neo-Lamarckism" or more commonly, epigenetic inheritance. It is a version of evolution that is as valid as the more well-known Neo-Darwinian theory.
Evolution by Adaptation
One of the most widespread misconceptions about evolution is that it is driven by a sort of struggle for survival. This view is inaccurate and overlooks other forces that drive evolution. The fight for survival can be more effectively described as a struggle to survive within a particular environment, which could involve not only other organisms but also the physical environment.
Understanding the concept of adaptation is crucial to understand evolution. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce in its environment. It could be a physical feature, like feathers or fur. It could also be a behavior trait that allows you to move to the shade during hot weather or escaping the cold at night.
The capacity of an organism to extract energy from its surroundings and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism needs to have the right genes to generate offspring, and it must be able to locate enough food and other resources. The organism should also be able to reproduce itself at a rate that is optimal for its particular niche.
These elements, in conjunction with mutation and gene flow result in a change in the proportion of alleles (different forms of a gene) in the population's gene pool. As time passes, this shift in allele frequencies could result in the development of new traits, and eventually new species.
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 for hiding. To understand adaptation, it is important to discern between physiological and behavioral characteristics.
Physical traits such as thick fur and gills are physical traits. Behavioral adaptations are not like the tendency of animals to seek companionship or to retreat into the shade in hot weather. It is important to remember that a lack of planning does not result in an adaptation. Inability to think about the effects of a behavior even if it seems to be rational, could make it inflexible.