What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can cause them to develop over time. This includes the appearance and growth of new species.
This has been proven by many examples such as the 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 trait permutations however, are not able to explain fundamental changes in body plans.
Evolution through Natural Selection
Scientists have been fascinated by the evolution of all the living creatures that inhabit our planet for ages. The most well-known explanation is Charles Darwin's natural selection process, an evolutionary process that occurs when individuals that are better adapted survive and reproduce more effectively than those that are less well adapted. As time passes, the number of individuals who are well-adapted grows and eventually forms an entirely new species.
Natural selection is an ongoing process that involves the interaction of three elements including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within an animal species. Inheritance refers the transmission of a person’s genetic characteristics, which includes recessive and dominant genes and their offspring. Reproduction is the process of generating fertile, viable offspring. This can be done by both asexual or sexual methods.
Natural selection can only occur when all of these factors are in equilibrium. For example, if a dominant allele at one gene can cause an organism to live and reproduce more often than the recessive allele, the dominant allele will be more prevalent within the population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will be eliminated. This process is self-reinforcing meaning that an organism with a beneficial characteristic will survive and reproduce more than an individual with a maladaptive characteristic. The more offspring an organism can produce the more fit it is which is measured by its ability to reproduce itself and survive. People with desirable traits, like a long neck in Giraffes, or the bright white color patterns on male peacocks are more likely to others to live and reproduce which eventually leads to them becoming the majority.
Natural selection only affects populations, not on individual organisms. This is a significant distinction from the Lamarckian evolution theory, which states that animals acquire traits due to use or lack of use. For example, if a animal's neck is lengthened by stretching to reach for prey its offspring will inherit a larger neck. The differences in neck length between generations will persist until the giraffe's neck gets so long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles at a gene may be at different frequencies in a group due to random events. At some point, only one of them will be fixed (become widespread enough to not more be eliminated through natural selection), and the rest of the alleles will diminish in frequency. In the extreme, this leads to dominance of a single allele. The other alleles have been basically eliminated and heterozygosity has been reduced to a minimum. In a small group this could lead to the complete elimination of recessive gene. This is known as the bottleneck effect and is typical of an evolution process that occurs when a large number individuals migrate to form a population.
A phenotypic bottleneck may also occur when survivors of a disaster like an outbreak or a mass hunting event are confined to a small area. The survivors will share an allele that is dominant and will share the same phenotype. This could be caused by a conflict, earthquake or even a disease. Whatever the reason the genetically distinct population that remains is susceptible to genetic drift.
Walsh Lewens and Ariew employ Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any departure from the expected values of differences in fitness. 에볼루션 카지노 cite the famous example of twins that are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, whereas the other continues to reproduce.
This kind of drift could play a crucial role in the evolution of an organism. However, 에볼루션 카지노 is not the only way to evolve. Natural selection is the primary alternative, where mutations and migrations maintain the phenotypic diversity in a population.
Stephens claims that there is a major distinction between treating drift as a force or a cause and considering other causes of evolution such as selection, mutation and migration as causes or causes. He claims that a causal-process explanation of drift lets us differentiate it from other forces and this distinction is essential. He further argues that drift has an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined by population size.
Evolution by Lamarckism
When students in high school take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is generally called "Lamarckism" and it states that simple organisms develop into more complex organisms by the inherited characteristics which result from the natural activities of an organism use and misuse. Lamarckism is usually illustrated with a picture of a giraffe that extends its neck to reach leaves higher up in the trees. This could cause giraffes to pass on their longer necks to offspring, who then become taller.
Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th of May in 1802, he presented an original idea that fundamentally challenged the conventional wisdom about organic transformation. In his opinion living things had evolved from inanimate matter via a series of gradual steps. Lamarck wasn't the first to propose this, but he was widely regarded as the first to offer the subject a comprehensive and general overview.
The most popular 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 call the Modern Synthesis. The theory argues that traits acquired through evolution can be inherited, and instead suggests that organisms evolve through the action of environmental factors, including natural selection.
While Lamarck endorsed the idea of inheritance through acquired characters and his contemporaries offered a few words about this idea but it was not an integral part of any of their evolutionary theories. This is due to the fact that it was never scientifically tested.
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 characteristics. This is referred to as "neo Lamarckism", or more commonly epigenetic inheritance. It is a version of evolution that is just as valid as the more well-known Neo-Darwinian theory.
Evolution through Adaptation
One of the most common misconceptions about evolution is that it is a result of a kind of struggle for survival. In fact, this view misrepresents natural selection and ignores the other forces that are driving evolution. The struggle for existence is better described as a struggle to survive in a particular environment. This may include not just other organisms, but also the physical environment.
To understand how evolution functions it is beneficial to think about what adaptation is. Adaptation is any feature that allows a living organism to survive in its environment and reproduce. It can be a physical structure such as feathers or fur. Or it can be a characteristic of behavior, like moving into the shade during hot weather, or escaping the cold at night.
The ability of an organism to draw energy from its surroundings and interact with other organisms and their physical environment is essential to its survival. The organism must possess the right genes to produce offspring and be able find enough food and resources. Furthermore, the organism needs to be capable of reproducing in a way that is optimally within its niche.
These factors, in conjunction with mutations and gene flow can cause an alteration in the ratio of different alleles in the gene pool of a population. As time passes, this shift in allele frequencies could lead to the emergence of new traits, and eventually new species.
A lot of the traits we admire in animals and plants are adaptations, such as lungs or gills to extract oxygen from the air, fur or feathers for insulation, long legs for running away from predators, and camouflage for hiding. To understand adaptation, it is important to differentiate between physiological and behavioral traits.
Physiological adaptations, such as thick fur or gills, are physical traits, whereas behavioral adaptations, like the tendency to search for friends or to move into the shade in hot weather, are not. Furthermore it is important to remember that a lack of forethought is not a reason to make something an adaptation. In fact, a failure to think about the implications of a decision can render it unadaptable despite the fact that it might appear reasonable or even essential.