What is Free Evolution?
Free evolution is the idea that the natural processes of living organisms can lead them to evolve over time. This includes the appearance and development of new species.
This has been demonstrated by many examples of stickleback fish species that can be found in saltwater or fresh water and walking stick insect types that are apprehensive about particular host plants. These reversible traits however, are not able to explain fundamental changes in basic body plans.
Evolution through Natural Selection
The development of the myriad living creatures on Earth is an enigma that has fascinated scientists for centuries. The best-established explanation is that of Charles Darwin's natural selection process, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well-adapted. Over time, a population of well adapted individuals grows and eventually creates a 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 mutation and sexual reproduction both of which increase the genetic diversity within the species. Inheritance refers to the transmission of a person's genetic characteristics, which includes recessive and dominant genes, to their offspring. Reproduction is the process of producing viable, fertile offspring. This can be accomplished through sexual or asexual methods.
All of these variables must be in harmony to allow natural selection to take place. If, for instance, a dominant gene allele allows an organism to reproduce and live longer than the recessive allele The dominant allele becomes more prevalent in a population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will disappear. The process is self reinforcing meaning that the organism with an adaptive trait will survive and reproduce much more than one with a maladaptive characteristic. The more offspring an organism produces the more fit it is, which is measured by its ability to reproduce itself and survive. People with desirable characteristics, such as a long neck in the giraffe, or bright white patterns on male peacocks are more likely to others to survive and reproduce, which will eventually lead to them becoming the majority.
Natural selection only acts on populations, not individuals. This is a significant distinction from the Lamarckian theory of evolution, which claims that animals acquire traits by use or inactivity. For instance, if a Giraffe's neck grows longer due to stretching to reach for prey and its offspring will inherit a larger neck. The difference in neck size between generations will continue to grow until the giraffe is no longer able to breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, the alleles at a gene may be at different frequencies within a population through random events. Eventually, one of them will attain fixation (become so common that it can no longer be removed through natural selection), while the other alleles drop to lower frequencies. This can result in an allele that is dominant at the extreme. The other alleles are virtually eliminated and heterozygosity decreased to a minimum. In a small group, this could lead to the total elimination of recessive alleles. This is known as the bottleneck effect. It is typical of an evolution process that occurs when the number of individuals migrate to form a group.
A phenotypic bottleneck may occur when survivors of a catastrophe such as an epidemic or mass hunting event, are condensed in a limited area. The survivors are likely to be homozygous for the dominant allele, which means that they will all share the same phenotype and therefore have the same fitness traits. This could be caused by war, earthquakes, or even plagues. The genetically distinct population, if left vulnerable to genetic drift.
Walsh Lewens, Lewens, and Ariew use Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from expected values for different fitness levels. They provide a well-known instance of twins who are genetically identical and have identical phenotypes, but one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could play a crucial role in the evolution of an organism. This isn't the only method for evolution. Natural selection is the most common alternative, in which mutations and migrations maintain the phenotypic diversity of the population.
Stephens asserts that there is a vast difference between treating the phenomenon of drift as an agent or cause and treating other causes like selection mutation and migration as forces and causes. He argues that a causal mechanism account of drift allows us to distinguish it from other forces, and that this distinction is essential. He argues further that drift is both a direction, i.e., it tends to reduce heterozygosity. It also has a size, which is determined based on the size of the population.
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 adopting traits that result from the use and abuse of an organism. Lamarckism is typically illustrated by the image of a giraffe that extends its neck further to reach higher up in the trees. This could cause the longer necks of giraffes to be passed onto their offspring who would grow taller.
Lamarck the French Zoologist from France, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to Lamarck, living things evolved from inanimate material through a series of gradual 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 its first broad and comprehensive treatment.
The dominant story is that Charles Darwin's theory of natural selection and Lamarckism were rivals in the 19th century. Darwinism eventually won and led to the creation of what biologists now call the Modern Synthesis. This 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 endorsed the idea of inheritance by acquired characters, and his contemporaries also offered a few words about this idea however, it was not a major feature in any of their evolutionary theorizing. Full Content is due to the fact that it was never scientifically validated.
But it is now 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. It is sometimes called "neo-Lamarckism" or, more commonly epigenetic inheritance. This is a version that is as reliable as the popular Neodarwinian model.
Evolution by Adaptation
One of the most common misconceptions about evolution is that it is driven by a type of struggle to survive. In reality, this notion misrepresents natural selection and ignores the other forces that drive evolution. The fight for survival can be more effectively described as a struggle to survive within a particular environment, which may involve not only other organisms, but also the physical environment.
To understand how evolution operates it is important to understand what is adaptation. Adaptation is any feature that allows living organisms to survive in its environment and reproduce. It can be a physiological structure, such as feathers or fur or a behavioral characteristic, such as moving into the shade in hot weather or coming out at night to avoid cold.
An organism's survival depends on its ability to draw energy from the environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes to create offspring and be able find sufficient food and resources. Furthermore, the organism needs to be able to reproduce itself at a high rate within its niche.
These factors, together with gene flow and mutations, can lead to a shift in the proportion of different alleles within the gene pool of a population. The change in frequency of alleles could lead to the development of new traits, and eventually new species as time passes.
Many of the characteristics we admire in animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, fur or feathers for insulation and long legs for running away from predators, and camouflage to hide. To understand the concept of adaptation, it is important to differentiate between physiological and behavioral characteristics.
Physical traits such as large gills and thick fur are physical characteristics. The behavioral adaptations aren't like the tendency of animals to seek companionship or retreat into shade during hot temperatures. In addition, it is important to understand that a lack of thought is not a reason to make something an adaptation. Inability to think about the consequences of a decision, even if it appears to be logical, can cause it to be unadaptive.