What is Free Evolution?
Free evolution is the notion that the natural processes that organisms go through can lead them to evolve over time. This includes the emergence and development of new species.
talks about it have been given of this, including different kinds of stickleback fish that can live in fresh or salt water and walking stick insect varieties that prefer specific host plants. These mostly reversible traits permutations do not explain the fundamental changes in basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living organisms that inhabit our planet for many centuries. The best-established explanation is that of Charles Darwin's natural selection process, a process that is triggered when more well-adapted individuals live longer and reproduce more successfully than those that are less well adapted. As time passes, the number of individuals who are well-adapted grows and eventually creates a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within an animal species. Inheritance is the passing of a person's genetic traits to the offspring of that person which includes both recessive and dominant alleles. Reproduction is the process of creating viable, fertile offspring. This can be achieved through sexual or asexual methods.
Natural selection only occurs when all the factors are in balance. For instance the case where a dominant allele at the gene can cause an organism to live and reproduce more often than the recessive one, the dominant allele will be more prominent within the population. But if the allele confers an unfavorable survival advantage or decreases fertility, it will be eliminated from the population. The process is self reinforcing which means that an organism that has an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive feature. The greater an organism's fitness which is measured by its ability to reproduce and survive, is the more offspring it can produce. People with desirable traits, like a long neck in giraffes, or bright white color patterns on male peacocks, are more likely than others to reproduce and survive and eventually lead to them becoming the majority.
Natural selection is only an element in the population and not on individuals. This is a significant distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics by use or inactivity. If a giraffe stretches its neck in order to catch prey and the neck grows larger, then its children will inherit this characteristic. The differences in neck size between generations will continue to grow until the giraffe is unable to breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed within a population. Eventually, one of them will reach fixation (become so widespread that it can no longer be removed by natural selection) and other alleles will fall to lower frequencies. In the extreme it can lead to dominance of a single allele. Other alleles have been essentially eliminated and heterozygosity has been reduced to a minimum. In a small group, this could lead to the complete elimination of the recessive allele. This is known as the bottleneck effect. It is typical of an evolution process that occurs when an enormous number of individuals move to form a group.
A phenotypic 'bottleneck' can also occur when survivors of a disaster such as an outbreak or mass hunting incident are concentrated in a small area. The survivors will carry a dominant allele and thus will have the same phenotype. This could be caused by war, an earthquake, or even a plague. Regardless of the cause the genetically distinct group that remains could be susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew use Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for differences in fitness. They give a famous example of twins that are genetically identical, have identical phenotypes and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift can be crucial in the evolution of a species. It is not the only method for evolution. My Source is the primary alternative, where mutations and migration keep the phenotypic diversity of a population.
Stephens asserts that there is a huge difference between treating the phenomenon of drift as an actual cause or force, and considering other causes, such as migration and selection mutation as causes and forces. Stephens claims that a causal process explanation of drift lets us differentiate it from other forces and that this distinction is essential. He also argues that drift has direction, i.e., it tends to eliminate heterozygosity. It also has a size which is determined by population size.
Evolution through Lamarckism
When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as "Lamarckism is based on the idea that simple organisms evolve into more complex organisms taking on traits that result from the organism's use and misuse. Lamarckism is usually illustrated with a picture of a giraffe stretching its neck to reach higher up in the trees. This could cause giraffes to give their longer necks to offspring, who then get taller.
Lamarck was a French Zoologist. In his opening lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on 17 May 1802, he presented an original idea that fundamentally challenged the conventional wisdom about organic transformation. According to Lamarck, living creatures evolved from inanimate material through a series of gradual steps. Lamarck was not the first to propose this, but he was widely considered to be the first to give the subject a comprehensive and general explanation.
The prevailing story is that Lamarckism became an opponent to Charles Darwin's theory of evolution by natural selection, and that the two theories battled it out in the 19th century. Darwinism ultimately prevailed, leading to what biologists call the Modern Synthesis. This theory denies acquired characteristics can be passed down and instead argues organisms evolve by the selective action of environment factors, such as Natural Selection.
While Lamarck supported the notion of inheritance through acquired characters and his contemporaries paid lip-service to this notion, it was never a central element in any of their evolutionary theories. This is partly because it was never scientifically validated.
It has been more than 200 years since the birth of Lamarck, and in the age genomics, there is an increasing evidence-based body of evidence to support the heritability of acquired traits. This is sometimes called "neo-Lamarckism" or, more often epigenetic inheritance. It is a version of evolution that is just as valid as the more well-known neo-Darwinian model.
Evolution by the process of adaptation
One of the most popular misconceptions about evolution is being driven by a struggle to survive. This view is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The fight for survival is more accurately described as a struggle to survive in a certain environment. This could include not only other organisms as well as the physical surroundings themselves.
To understand how evolution operates, it is helpful to understand what is adaptation. Adaptation refers to any particular characteristic that allows an organism to survive and reproduce within its environment. It could be a physiological feature, such as feathers or fur or a behavior such as a tendency to move to the shade during the heat or leaving 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 environment is essential to its survival. The organism must have the right genes to produce offspring, and be able to find enough food and resources. The organism should also be able reproduce itself at an amount that is appropriate for its particular niche.
These elements, along with gene flow and mutations can cause a shift in the proportion of different alleles in the gene pool of a population. This change in allele frequency can result in the emergence of new traits, and eventually new species as time passes.
A lot of the traits we admire in animals and plants are adaptations, such as the lungs or gills that extract oxygen from the air, feathers or fur to provide insulation, long legs for running away from predators, and camouflage for hiding. However, a thorough understanding of adaptation requires a keen eye to the distinction between behavioral and physiological traits.
Physiological adaptations, like thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to seek out companions or to retreat to shade in hot weather, aren't. It is also important to keep in mind that insufficient planning does not make an adaptation. Inability to think about the implications of a choice, even if it appears to be rational, could cause it to be unadaptive.