What is Free Evolution?
Free evolution is the idea that natural processes can lead to the development of organisms over time. This includes the creation of new species as well as the transformation of the appearance of existing ones.
This has been demonstrated by many examples, including stickleback fish varieties that can thrive in fresh or saltwater and walking stick insect species that prefer particular host plants. These reversible traits are not able to explain fundamental changes to basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all living creatures that inhabit our planet for ages. The most widely accepted explanation is Darwin's natural selection, a process that occurs when better-adapted individuals survive and reproduce more successfully than those 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 3 factors including reproduction, variation and inheritance. Mutation and sexual reproduction increase the genetic diversity of a species. Inheritance is the term used to describe the transmission of a person’s genetic characteristics, which includes recessive and dominant genes and their offspring. Reproduction is the process of producing fertile, viable offspring, which includes both sexual and asexual methods.
All of these factors must be in harmony to allow natural selection to take place. If, for our homepage , a dominant gene allele causes an organism reproduce and last longer than the recessive gene allele The dominant allele will become more prevalent in a group. 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 characteristic will live and reproduce far more effectively than one with a maladaptive characteristic. The more fit an organism is, measured by its ability reproduce and survive, is the more offspring it can produce. Individuals with favorable characteristics, such as a long neck in giraffes, or bright white patterns on male peacocks are more likely to others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection only acts on populations, not on individuals. This is a major distinction from the Lamarckian theory of evolution which claims that animals acquire traits by use or inactivity. For instance, if the giraffe's neck gets longer through stretching to reach for prey its offspring will inherit a longer neck. The differences in neck length between generations will persist until the neck of the giraffe becomes so long that it can not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a group. In the end, one will attain fixation (become so widespread that it cannot be eliminated by natural selection) and other alleles will fall to lower frequencies. This could lead to a dominant allele at the extreme. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small group, this could result in the complete elimination of the recessive gene. This scenario is called the bottleneck effect. It is typical of an evolutionary process that occurs when an enormous number of individuals move to form a group.
A phenotypic bottleneck can also occur when the survivors of a disaster such as an epidemic or a massive hunting event, are condensed within a narrow area. The survivors will have a dominant allele and thus will share the same phenotype. This situation might be caused by a conflict, earthquake, or even a plague. The genetically distinct population, if it is left vulnerable to genetic drift.
Walsh Lewens and Ariew utilize Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any departure from the expected values of differences in fitness. They cite the famous example of twins that are genetically identical and have exactly the same phenotype. However, one is struck by lightning and dies, whereas the other lives to reproduce.
This type of drift is very important in the evolution of a species. It is not the only method for evolution. Natural selection is the primary alternative, where mutations and migrations maintain the phenotypic diversity in the population.
Stephens argues that there is a big difference between treating drift as a force or as a cause and considering other causes of evolution such as selection, mutation and migration as causes or causes. He claims that a causal mechanism account of drift permits us to differentiate it from other forces, and that this distinction is essential. He also claims that drift has a direction: that is it tends to reduce heterozygosity. He also claims that it also has a size, which is determined by population size.
Evolution through Lamarckism
Students of biology in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is often referred to as "Lamarckism" and it states that simple organisms grow into more complex organisms by the inheritance of traits which result from an organism's natural activities, use and disuse. Lamarckism can be demonstrated by the giraffe's neck being extended to reach higher levels of leaves in the trees. This process would cause giraffes to give their longer necks to offspring, who then get taller.
Lamarck, a French Zoologist, introduced an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According to Lamarck, living creatures evolved from inanimate materials through a series of gradual steps. 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 its first general and comprehensive treatment.
The prevailing story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution by natural selection, and that the two theories fought out in the 19th century. Darwinism eventually prevailed which led to what biologists refer to as the Modern Synthesis. This theory denies acquired characteristics can be passed down and instead argues organisms evolve by the influence of environment factors, including Natural Selection.
Lamarck and his contemporaries believed in the notion that acquired characters could be passed down to the next generation. However, this notion was never a central part of any of their evolutionary theories. This is partly because it was never scientifically tested.
But it is now more than 200 years since Lamarck was born and in the age genomics, there is a large amount of evidence that supports the possibility of inheritance of acquired traits. This is referred to as "neo Lamarckism", or more often epigenetic inheritance. It is a variant of evolution that is as valid as the more popular Neo-Darwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. In reality, this notion is a misrepresentation of natural selection and ignores the other forces that drive evolution. The fight for survival can be better described as a fight to survive in a specific environment. This could include not just other organisms but also the physical environment.
To understand how evolution operates it is beneficial to understand what is adaptation. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce within its environment. It can be a physical feature, like fur or feathers. It could also be a behavior trait, like moving into the shade during the heat, or coming out to avoid the cold at night.
An organism's survival depends on its ability to obtain energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism must possess the right genes to generate offspring, and it must be able to access enough food and other resources. In addition, the organism should be capable of reproducing in a way that is optimally within its environmental niche.
These factors, together with gene flow and mutations can cause a shift in the proportion of different alleles in the gene pool of a population. This shift in the frequency of alleles can lead to the emergence of new traits, and eventually, new species as time passes.
A lot of the traits we find appealing in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from the air feathers and fur as insulation and long legs to get away from predators and camouflage for hiding. However, a complete understanding of adaptation requires paying attention to the distinction between the physiological and behavioral traits.
Physiological adaptations like the thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the desire to find companions or to retreat into the shade in hot weather, are not. Additionally it is important to note that lack of planning does not make something an adaptation. In fact, failure to consider the consequences of a decision can render it unadaptive even though it appears to be reasonable or even essential.