What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to evolve over time. This includes the creation of new species and alteration of the appearance of existing ones.
This has been proven by numerous examples of stickleback fish species that can live in fresh or saltwater and walking stick insect species that prefer specific host plants. These mostly reversible trait permutations can't, however, be the reason for fundamental changes in body plans.
Evolution by Natural Selection
The evolution of the myriad living creatures on Earth is a mystery that has fascinated scientists for many centuries. Charles Darwin's natural selection theory is the most well-known explanation. This process occurs when people who are more well-adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, a population of well-adapted individuals expands and eventually creates a new species.
Natural selection is a cyclical process that involves the interaction of three factors that are inheritance, variation and reproduction. Mutation and sexual reproduction increase the genetic diversity of an animal species. Inheritance is the passing of a person's genetic characteristics to their offspring which includes both recessive and dominant alleles. Reproduction is the process of producing fertile, viable offspring. This can be done through sexual or asexual methods.
Natural selection only occurs when all of these factors are in equilibrium. For instance, if a dominant allele at the gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will be more prevalent in the population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will go away. The 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 trait. The more offspring an organism can produce the better its fitness, which is measured by its ability to reproduce and survive. People with good characteristics, such as having a long neck in Giraffes, or the bright white patterns on male peacocks, are more likely than others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection only acts on populations, not individuals. This is a major distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or neglect. For example, if a giraffe's neck gets longer through reaching out to catch prey its offspring will inherit a longer neck. The differences in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles at a gene may attain different frequencies in a group by chance events. At some point, only one of them will be fixed (become common enough to no more be eliminated through natural selection) and the rest of the alleles will drop in frequency. In the extreme this, it leads to one allele dominance. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small number of people this could lead to the complete elimination of the recessive gene. This scenario is called the bottleneck effect and is typical of an evolutionary process that occurs when a large number individuals migrate to form a group.
A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or mass hunt incident are concentrated in the same area. The survivors will share an allele that is dominant and will share the same phenotype. This situation could be caused by earthquakes, war or even plagues. The genetically distinct population, if left vulnerable to genetic drift.
Walsh Lewens, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any deviation from expected values for differences in fitness. They provide the famous case of twins who are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, while the other is able to reproduce.
This kind of drift can be very important in the evolution of the species. However, it is not the only method to progress. The most common alternative is a process known as natural selection, where the phenotypic diversity of the population is maintained through mutation and migration.
Stephens asserts that there is a vast difference between treating the phenomenon of drift as an actual cause or force, and considering other causes, such as migration and selection mutation as forces and causes. He argues that a causal mechanism account of drift permits us to differentiate it from these other forces, and that this distinction is crucial. He further argues that drift has a direction, that is it tends to eliminate heterozygosity. He also claims that it also has a size, which is determined by the size of population.
Evolution through Lamarckism
When students in high school take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). Recommended Looking at of evolution, also called "Lamarckism is based on the idea that simple organisms develop into more complex organisms through inheriting characteristics that are a product of the use and abuse of an organism. Lamarckism is typically illustrated with the image of a giraffe that extends its neck longer to reach the higher branches in the trees. This could result in giraffes passing on their longer necks to offspring, who would then grow even taller.
Lamarck was a French zoologist and, in his opening lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th May 1802, he introduced a groundbreaking concept that radically challenged previous thinking about organic transformation. In his opinion living things had evolved from inanimate matter through an escalating series of steps. Lamarck was not the first to suggest this but he was thought of as the first to offer the subject a comprehensive and general explanation.
The most popular story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were rivals in the 19th century. Darwinism eventually won, leading to the development of what biologists today call the Modern Synthesis. The theory argues that acquired traits can be passed down through generations and instead argues organisms evolve by the selective action of environment elements, like Natural Selection.
Lamarck and his contemporaries supported the idea that acquired characters could be passed down to the next generation. However, this idea was never a major part of any of their theories on evolution. This is due in part to the fact that it was never tested scientifically.
But it is now more than 200 years since Lamarck was born and in the age genomics, there is a large body of evidence supporting the possibility of inheritance of acquired traits. This is also known as "neo Lamarckism", or more generally epigenetic inheritance. It is a form of evolution that is as valid as the more well-known Neo-Darwinian model.
Evolution by Adaptation
One of the most popular misconceptions about evolution is its being driven by a struggle for survival. This notion is not true and overlooks other forces that drive evolution. The struggle for survival is more precisely described as a fight to survive within a particular environment, which may be a struggle that involves not only other organisms but also the physical environment.
Understanding how adaptation works is essential to understand evolution. Adaptation is any feature that allows living organisms to live in its environment and reproduce. It could be a physiological structure such as feathers or fur or a behavioral characteristic such as a tendency to move into shade in hot weather or stepping out at night to avoid cold.
The survival of an organism depends on its ability to extract energy from the surrounding environment and interact with other organisms and their physical environments. The organism must have the right genes to produce offspring, and it must be able to access sufficient food and other resources. Furthermore, the organism needs to be able to reproduce itself at a high rate within its environment.
These elements, along with gene flow and mutations, can lead to changes in the proportion of different alleles within a population’s gene pool. This change in allele frequency can result in the emergence of new traits and eventually, new species over time.
Many of the features that we admire in animals and plants are adaptations, like lung or gills for removing oxygen from the air, feathers or fur for insulation long legs to run away from predators and camouflage for hiding. To comprehend adaptation, it is important to discern between physiological and behavioral characteristics.
Physical traits such as thick fur and gills are physical characteristics. Behavior adaptations aren't like the tendency of animals to seek companionship or to retreat into the shade in hot temperatures. In addition, it is important to note that lack of planning does not mean that something is an adaptation. Failure to consider the effects of a behavior, even if it appears to be rational, may make it unadaptive.