What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to evolve over time. 에볼루션 무료체험 includes the creation of new species and the change in appearance of existing ones.
A variety of examples have been provided of this, including different varieties of stickleback fish that can be found in fresh or salt water and walking stick insect varieties that are attracted to particular host plants. These reversible traits cannot explain fundamental changes to the basic body plan.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living creatures that inhabit our planet for ages. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when those who are better adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, a community of well-adapted individuals increases and eventually forms a whole new species.
Natural selection is an ongoing process that involves the interaction of three elements: variation, inheritance and reproduction. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity of the species. Inheritance refers to the transmission of a person’s genetic traits, including both dominant and recessive genes, to their offspring. Reproduction is the process of producing viable, fertile offspring. This can be done via sexual or asexual methods.
Natural selection can only occur when all these elements are in harmony. If, for example the dominant gene allele causes an organism reproduce and last longer than the recessive gene allele, then the dominant allele will become more prevalent in a population. If the allele confers a negative advantage to survival or reduces the fertility of the population, it will be eliminated. The process is self reinforcing meaning that an organism that has an adaptive characteristic will live and reproduce much more than one with a maladaptive characteristic. The more offspring an organism can produce the more fit it is which is measured by its capacity to reproduce itself and live. Individuals with favorable traits, such as having a longer neck in giraffes or bright white colors in male peacocks are more likely to survive and have offspring, and thus will make up the majority of the population over time.
Natural selection is only a force for populations, not individual organisms. This is a crucial distinction from the Lamarckian evolution theory, which states that animals acquire traits through the use or absence of use. For instance, if a Giraffe's neck grows longer due to stretching to reach prey its offspring will inherit a more long neck. The difference in neck size between generations will continue to increase until the giraffe becomes unable to breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles at a gene may attain different frequencies in a population through random events. In the end, one will reach fixation (become so common that it is unable to be removed through natural selection), while other alleles will fall to lower frequencies. This can result in an allele that is dominant in extreme. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small number of people this could lead to the complete elimination the recessive gene. This scenario is known as a bottleneck effect and it is typical of evolutionary process that occurs when a large amount of individuals migrate to form a new group.
A phenotypic bottleneck may occur when the survivors of a disaster, such as an epidemic or a massive hunt, are confined in a limited area. The remaining individuals are likely to be homozygous for the dominant allele meaning that they all have the same phenotype and thus share the same fitness characteristics. This can be caused by war, earthquakes or even a plague. Regardless of the cause the genetically distinct group that remains could be prone to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a deviation from the expected value due to differences in fitness. They cite the famous example of twins who are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, while the other continues to reproduce.
This kind of drift can be crucial in the evolution of a species. However, it's not the only way to progress. Natural selection is the primary alternative, where mutations and migration maintain phenotypic diversity within a population.
Stephens asserts that there is a huge difference between treating the phenomenon of drift as an agent or cause and treating other causes like migration and selection mutation as forces and causes. Stephens claims that a causal process explanation of drift lets us separate it from other forces, and this distinction is essential. He further argues that drift has a direction: that is, it tends to eliminate heterozygosity, and that it also has a size, which is determined by the size of population.
Evolution by Lamarckism
When students in high school study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is commonly known as "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of characteristics that are a result of an organism's natural activities, use and disuse. Lamarckism is illustrated through the giraffe's neck being extended to reach higher levels of leaves in the trees. This process would cause giraffes to pass on their longer necks to offspring, which then grow even taller.
Lamarck Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. In his view, living things had evolved from inanimate matter through the gradual progression of events. Lamarck was not the first to suggest that this might be the case but his reputation is widely regarded as having given the subject his first comprehensive and thorough treatment.
The predominant story is that Charles Darwin's theory on natural selection and Lamarckism were rivals during the 19th century. Darwinism ultimately won and led to what biologists refer to as the Modern Synthesis. This theory denies that acquired characteristics can be inherited and instead suggests that organisms evolve by the symbiosis of environmental factors, such as natural selection.
While Lamarck supported the notion of inheritance through acquired characters and his contemporaries spoke of this idea, it was never a central element in any of their theories about evolution. This is due to the fact that it was never scientifically validated.
It's been more than 200 years since Lamarck was born and in the age genomics there is a vast amount of evidence to support the possibility of inheritance of acquired traits. This is often referred to as "neo-Lamarckism" or more commonly epigenetic inheritance. It is a form of evolution that is as valid as the more popular neo-Darwinian model.
Evolution by adaptation
One of the most widespread misconceptions about evolution is that it is driven by a type of struggle to survive. This view is inaccurate and ignores other forces driving evolution. The fight for survival can be more accurately described as a struggle to survive in a specific environment, which can involve not only other organisms but also the physical environment.
Understanding adaptation is important to understand evolution. It refers to a specific feature that allows an organism to survive and reproduce in its environment. It could be a physiological feature, such as fur or feathers or a behavioral characteristic such as a tendency to move into shade in hot weather or coming out at night to avoid 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 possess the right genes to produce offspring, and it should be able to access sufficient food and other resources. Furthermore, the organism needs to be able to reproduce itself at an optimal rate within its environment.
These factors, in conjunction with mutations and gene flow, can lead to an alteration in the ratio of different alleles within a population’s gene pool. This change in allele frequency can lead to the emergence of new traits and eventually, new species over time.
Many of the characteristics we admire in animals and plants are adaptations. For instance the lungs or gills which draw oxygen from air feathers and fur as insulation long legs to run away from predators and camouflage for hiding. However, a thorough understanding of adaptation requires attention to the distinction between behavioral and physiological characteristics.
Physiological traits like the thick fur and gills are physical characteristics. Behavioral adaptations are not, such as the tendency of animals to seek companionship or retreat into shade during hot weather. Furthermore it is important to note that a lack of thought does not mean that something is an adaptation. Inability to think about the consequences of a decision even if it appears to be rational, could make it unadaptive.