What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can lead to their development over time. This includes the creation of new species and the alteration of the appearance of existing species.
This has been proven by many examples, including stickleback fish varieties that can be found in salt or fresh water, and walking stick insect types that prefer particular host plants. These reversible traits can't, however, explain fundamental changes in body plans.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living creatures that live on our planet for ages. The most well-known 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. Over time, a community of well-adapted individuals increases and eventually creates a new species.
Natural selection is a process that is cyclical and involves the interaction of three factors including reproduction, variation and inheritance. Sexual reproduction and mutations increase genetic diversity in a species. Inheritance is the passing of a person's genetic characteristics to their offspring which includes both dominant and recessive alleles. Reproduction is the process of creating viable, fertile offspring. This can be done by both asexual or sexual methods.
All of these elements must be in harmony to allow natural selection to take place. If, for instance the dominant gene allele causes an organism reproduce and live longer than the recessive gene then the dominant allele becomes more prevalent in a population. However, if the allele confers an unfavorable survival advantage or decreases fertility, it will disappear from the population. The process is self-reinforcing, meaning that a species with a beneficial characteristic will survive and reproduce more than an individual with an inadaptive trait. The greater an organism's fitness as measured by its capacity to reproduce and endure, is the higher number of offspring it can produce. People with good traits, like a long neck in Giraffes, or the bright white color patterns on male peacocks are more likely to others to reproduce and survive and eventually lead to them becoming the majority.
Natural selection is an element in the population and not on individuals. This is a significant distinction from the Lamarckian evolution theory, which states that animals acquire traits due to use or lack of use. For example, if a Giraffe's neck grows longer due to reaching out to catch prey, its offspring will inherit a more long neck. The difference in neck length between generations will continue until the neck of the giraffe becomes so long that it can not breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, the alleles of a gene could reach different frequencies in a population through random events. In the end, one will attain fixation (become so widespread that it cannot be eliminated by natural selection), while the other alleles drop to lower frequencies. In extreme cases this, it leads to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small group it could result in the complete elimination of recessive gene. This is known as the bottleneck effect and is typical of an evolutionary process that occurs whenever an enormous number of individuals move to form a population.
A phenotypic bottleneck may also occur when the survivors of a catastrophe such as an outbreak or mass hunt event are confined to the same area. The survivors will share a dominant allele and thus will have the same phenotype. This can be caused by earthquakes, war, or even plagues. The genetically distinct population, if it remains, could be susceptible to genetic drift.
Walsh, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They provide the famous case of twins who are both genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, whereas the other lives to reproduce.
This kind of drift can be very important in the evolution of a species. This isn't the only method for evolution. The main alternative is a process called natural selection, in which the phenotypic diversity of a population is maintained by mutation and migration.
Stephens claims that there is a big difference between treating drift as a force or an underlying cause, and treating other causes of evolution such as mutation, selection, and migration as forces or causes. Stephens claims that a causal mechanism account of drift allows us to distinguish it from other forces, and this distinction is crucial. He argues further that drift is both a direction, i.e., it tends to eliminate heterozygosity. It also has a size, that is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution is often known as "Lamarckism" and it states that simple organisms grow into more complex organisms by the inherited characteristics that result from the organism's natural actions usage, use and disuse. Lamarckism is typically illustrated by a picture of a giraffe extending its neck to reach the higher branches in the trees. This could cause giraffes to pass on their longer necks to offspring, which then get taller.
Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. According to him living things had evolved from inanimate matter through the gradual progression of events. Lamarck was not the only one to suggest that this could be the case but the general consensus is that he was the one giving the subject his first comprehensive and comprehensive analysis.
The most popular story is that Lamarckism was a rival to Charles Darwin's theory of evolution through natural selection and both theories battled each other in the 19th century. Darwinism ultimately won which led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down through generations and instead, it claims that organisms evolve through the selective action of environment factors, including Natural Selection.
While Lamarck believed in the concept of inheritance through acquired characters, and his contemporaries also paid lip-service to this notion however, it was not an integral part of any of their evolutionary theorizing. This is due to the fact that it was never scientifically validated.
However, it has been more than 200 years since Lamarck was born and in the age genomics, there is a large amount of evidence to support the possibility of inheritance of acquired traits. 에볼루션카지노 is often called "neo-Lamarckism" or more commonly epigenetic inheritance. This is a model that is as reliable as the popular neodarwinian model.
Evolution by the process of adaptation
One of the most popular misconceptions about evolution is its being driven by a struggle for survival. This is a false assumption and overlooks other forces that drive evolution. The struggle for survival is more accurately described as a struggle to survive within a specific environment, which can be a struggle that involves not only other organisms, but as well the physical environment.
Understanding adaptation is important to understand evolution. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce within its environment. It could be a physiological structure, such as fur or feathers or a behavior such as a tendency to move into the shade in hot weather or coming out at night to avoid the cold.
The ability of an organism to extract energy from its environment and interact with other organisms, as well as their physical environments, is crucial to its survival. The organism must have the right genes to produce offspring, and must be able to find sufficient food and other resources. The organism should also be able to reproduce at a rate that is optimal for its specific niche.
These factors, together with mutations and gene flow, can lead to an alteration in the ratio of different alleles within the population's gene pool. As time passes, this shift in allele frequency can result in the emergence of new traits and eventually new species.
Many of the characteristics we find appealing 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 paying attention to the distinction between the physiological and behavioral traits.
Physiological traits like the thick fur and gills are physical characteristics. The behavioral adaptations aren't, such as the tendency of animals to seek out companionship or to retreat into the shade in hot temperatures. Furthermore, it is important to remember that a lack of forethought does not mean that something is an adaptation. Failure to consider the implications of a choice even if it appears to be logical, can make it unadaptive.