What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can cause them to develop over time. This includes the appearance and growth of new species.
This is evident in numerous examples of stickleback fish species that can thrive in fresh or saltwater and walking stick insect varieties that have a preference for particular host plants. These mostly reversible traits permutations are not able to explain fundamental changes to the basic body plan.
Evolution by Natural Selection
The evolution of the myriad living creatures on Earth is a mystery that has intrigued 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 less well-adapted. Over time, a population of well adapted individuals grows and eventually becomes a new species.
Natural selection is an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity of a species. Inheritance refers the transmission of a person’s genetic traits, including both dominant and recessive genes, to their offspring. Reproduction is the process of generating viable, fertile offspring. This can be achieved via sexual or asexual methods.
Natural selection only occurs when all of these factors are in harmony. For example the case where an allele that is dominant at one gene can cause an organism to live and reproduce more frequently than the recessive allele, the dominant allele will be more prevalent within the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will go away. The process is self-reinforcing meaning that an organism with an adaptive trait will live and reproduce far more effectively than one with a maladaptive characteristic. The more offspring an organism produces the better its fitness, which is measured by its capacity to reproduce and survive. 에볼루션게이밍 with good traits, such as longer necks in giraffes and bright white colors in male peacocks are more likely survive and have offspring, and thus will become the majority of the population in the future.
Natural selection is only a force for populations, not individuals. This is an important distinction from the Lamarckian theory of evolution which claims that animals acquire traits by use or inactivity. If a giraffe extends its neck to reach prey and its neck gets longer, then the children will inherit this characteristic. The differences in neck length between generations will persist until the neck of the giraffe becomes too long that it can not breed with other giraffes.
에볼루션게이밍 by Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed within a population. Eventually, only one will be fixed (become widespread enough to not more be eliminated through natural selection) and the other alleles will drop in frequency. In extreme cases it can lead to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small number of people it could lead to the total elimination of recessive allele. 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 like an outbreak or mass hunt incident are concentrated in a small area. The survivors will carry a dominant allele and thus will have the same phenotype. This could be the result of a conflict, earthquake or even a disease. The genetically distinct population, if left vulnerable to genetic drift.
Walsh, Lewens, and Ariew utilize Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They provide the famous case of twins that are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, while the other lives to reproduce.
This type of drift can play a significant role in the evolution of an organism. This isn't the only method for evolution. The most common alternative is a process known as natural selection, in which the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens argues there is a huge difference between treating the phenomenon of drift as an agent or cause and treating other causes such as migration and selection mutation as causes and forces. He claims that a causal-process explanation of drift lets us differentiate it from other forces, and this distinction is crucial. He also argues that drift has both an orientation, i.e., it tends to reduce heterozygosity. It also has a size which is determined based on the size of the population.
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 called "Lamarckism" and it asserts that simple organisms evolve into more complex organisms through the inheritance of characteristics that are a result of an organism's natural activities use and misuse. Lamarckism is typically illustrated by an image of a giraffe stretching its neck further to reach higher up in the trees. This would cause giraffes' longer necks to be passed to their offspring, who would then become taller.
Lamarck Lamarck, a French Zoologist from France, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged traditional thinking about organic transformation. According to him, living things had evolved from inanimate matter through an escalating series of 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 general and comprehensive analysis.
The predominant story is that Charles Darwin's theory on natural selection and Lamarckism were competing in the 19th Century. Darwinism eventually won and led to the development of what biologists call the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead, it claims that organisms evolve through the selective influence of environmental factors, including Natural Selection.
While Lamarck endorsed the idea of inheritance through acquired characters, and his contemporaries also paid lip-service to this notion but it was not a central element in any of their theories about evolution. This is partly due to the fact that it was never tested scientifically.
It's been over 200 years since the birth of Lamarck, and in the age genomics, there is a growing body of evidence that supports the heritability acquired characteristics. This is also referred to as "neo Lamarckism", or more generally epigenetic inheritance. It is a form of evolution that is just as relevant as the more popular Neo-Darwinian theory.
Evolution by the process of adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle to survive. In fact, this view misrepresents natural selection and ignores the other forces that are driving evolution. The fight for survival can be more accurately described as a struggle to survive within a particular environment, which could be a struggle that involves not only other organisms, but as well the physical environment.
Understanding the concept of adaptation is crucial to comprehend evolution. Adaptation refers to any particular characteristic that allows an organism to live and reproduce in its environment. It can be a physical structure, such as feathers or fur. Or it can be a characteristic of behavior such as moving into the shade during the heat, or moving out to avoid the cold at night.
The survival of an organism depends on its ability to draw energy from the environment and to interact with other living organisms and their physical surroundings. The organism should possess the right genes to produce offspring and be able find sufficient food and resources. The organism should also be able to reproduce itself at a rate that is optimal for its niche.
These elements, in conjunction with mutation and gene flow, lead to changes in the ratio of alleles (different varieties of a particular gene) in the population's gene pool. This shift in the frequency of alleles could lead to the development of new traits and eventually, new species as time passes.
Many of the features that we admire about animals and plants are adaptations, such as lungs or gills to extract oxygen from the air, feathers or fur for insulation, long legs for running away from predators and camouflage to hide. However, a thorough understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral characteristics.
Physiological adaptations, like the thick fur or gills are physical characteristics, whereas behavioral adaptations, like the tendency to seek out companions or to move to the shade during hot weather, aren't. Additionally it is important to remember that a lack of thought is not a reason to make something an adaptation. In fact, failing to consider the consequences of a decision can render it unadaptive even though it may appear to be reasonable or even essential.