Why Free Evolution Is Everywhere This Year
What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to develop over time. This includes the creation of new species and transformation of the appearance of existing species.
This has been demonstrated by many examples, including stickleback fish varieties that can live in saltwater or fresh water and walking stick insect types that prefer specific host plants. These reversible traits cannot explain fundamental changes to the basic body plan.
Evolution by Natural Selection
The evolution of the myriad living organisms on Earth is a mystery that has intrigued scientists for centuries. The best-established explanation is that of Charles Darwin's natural selection, which is triggered when more well-adapted individuals live longer and reproduce more successfully than those who are less well-adapted. As time passes, the number of individuals who are well-adapted grows and eventually forms a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Sexual reproduction and mutations increase the genetic diversity of a species. Inheritance is the passing of a person's genetic traits to his or her offspring which includes both recessive and dominant alleles. Reproduction is the process of producing fertile, viable offspring. This can be achieved through sexual or asexual methods.
Natural selection only occurs when all these elements are in harmony. If, for example, a dominant gene allele allows an organism to reproduce and survive more than the recessive gene then the dominant allele will become more prevalent in a group. If the allele confers a negative survival advantage or lowers the fertility of the population, it will go away. This process is self-reinforcing meaning that an organism with a beneficial trait can reproduce and survive longer than an individual with a maladaptive characteristic. The greater an organism's fitness which is measured by its ability to reproduce and endure, is the higher number of offspring it produces. People with good traits, like longer necks in giraffes or bright white colors in male peacocks are more likely survive and produce offspring, and thus will become the majority of the population in the future.
Natural selection is only an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which claims that animals acquire characteristics through use or disuse. For instance, if the giraffe's neck gets longer through reaching out to catch prey, its offspring will inherit a more long neck. The length difference between generations will continue until the neck of the giraffe becomes too long to not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles of one gene are distributed randomly in a population. In the end, only one will be fixed (become widespread enough to not more be eliminated through natural selection), and the other alleles will diminish in frequency. This can lead to dominance in extreme. 무료 에볼루션 are eliminated, and heterozygosity is reduced to zero. In a small number of people this could lead to the complete elimination the recessive gene. Such a scenario would be known as a bottleneck effect and it is typical of evolutionary process that takes place when a large amount of individuals migrate to form a new group.
A phenotypic bottleneck can also occur when survivors of a catastrophe like an epidemic or a massive hunt, are confined into a small area. The surviving individuals are likely to be homozygous for the dominant allele, which means they will all have the same phenotype, and therefore have the same fitness traits. This can be caused by earthquakes, war or even a plague. Regardless of the cause the genetically distinct group that remains is susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They give the famous example of twins that are genetically identical and share the same phenotype, but one is struck by lightning and dies, but the other continues to reproduce.
This kind of drift could play a significant part in the evolution of an organism. It is not the only method of evolution. Natural selection is the main alternative, where mutations and migrations maintain the phenotypic diversity in the population.
Stephens claims that there is a vast distinction between treating drift as an actual cause or force, and treating other causes such as migration and selection as forces and causes. He claims that a causal-process model of drift allows us to distinguish it from other forces and that this differentiation is crucial. He further argues that drift has an orientation, i.e., it tends to eliminate heterozygosity. It also has a size, which is determined by population size.
Evolution through Lamarckism
Students of biology in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is commonly known as "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of traits which result from an organism's natural activities, use and disuse. Lamarckism is typically illustrated by an image of a giraffe extending its neck to reach higher up in the trees. This process would result in giraffes passing on their longer necks to offspring, who would then grow even taller.
Lamarck the French Zoologist, introduced an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the conventional wisdom on organic transformation. According to him living things evolved from inanimate matter via a series of gradual steps. Lamarck wasn't the first to suggest this however he was widely regarded as the first to provide the subject a comprehensive and general overview.
The predominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were rivals during the 19th century. Darwinism eventually prevailed, leading to the development of what biologists now 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, like natural selection.
While Lamarck believed in the concept of inheritance through acquired characters, and his contemporaries also paid lip-service to this notion, it was never a major feature in any of their evolutionary theories. This is due to the fact that it was never tested scientifically.
It's been more than 200 years since Lamarck was born and in the age of genomics, there is a large body of evidence supporting the heritability of acquired traits. It is sometimes called "neo-Lamarckism" or, more frequently epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model.
Evolution by Adaptation
One of the most common misconceptions about evolution is its being driven by a struggle to survive. This notion is not true 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 could involve not only other organisms, but as well the physical environment.
Understanding adaptation is important to comprehend evolution. The term "adaptation" refers to any characteristic that allows living organisms to live in its environment and reproduce. It could be a physiological structure, such as fur or feathers or a behavior like moving into shade in hot weather or coming out at night to avoid the cold.
The capacity of a living thing to extract energy from its surroundings and interact with other organisms and their physical environments is essential to its survival. The organism needs to have the right genes to generate offspring, and it must be able to access sufficient food and other resources. The organism should also be able reproduce at a rate that is optimal for its niche.
These elements, in conjunction with gene flow and mutation can result in changes in the ratio of alleles (different varieties of a particular gene) in the gene pool of a population. This change in allele frequency can lead to 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, like lung or gills for removing oxygen from the air, fur or feathers for insulation, long legs for running away from predators and camouflage to hide. To comprehend adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physiological adaptations, like thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the tendency to search for companions or to move to shade in hot weather, are not. It is also important to remember that a the absence of planning doesn't result in an adaptation. In fact, a failure to consider the consequences of a decision can render it unadaptive despite the fact that it appears to be logical or even necessary.