What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can lead them to evolve over time. This includes the creation of new species and the transformation of the appearance of existing species.
This is evident in many examples, including stickleback fish varieties that can be found in saltwater or fresh water and walking stick insect varieties that have a preference for particular host plants. These reversible traits cannot explain fundamental changes to the body's basic plans.
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 selection theory is the most well-known explanation. This process occurs when those who are better adapted have more success in reproduction and survival than those who are less well-adapted. As time passes, the number of well-adapted individuals grows and eventually develops into a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity of the species. Inheritance refers the transmission of a person’s genetic traits, which include recessive and dominant genes, to their offspring. Reproduction is the production of fertile, viable offspring, which includes both asexual and sexual methods.
All of these factors have to be in equilibrium to allow natural selection to take place. If, for example the dominant gene allele causes an organism reproduce and live longer than the recessive gene The dominant allele becomes more common in a population. But if the allele confers an unfavorable survival advantage or decreases fertility, it will be eliminated from the population. The process is self-reinforcing, which means that the organism with an adaptive characteristic will live and reproduce much more than those with a maladaptive feature. The more fit an organism is, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with desirable characteristics, like longer necks in giraffes or bright white colors in male peacocks are more likely to survive and have offspring, and thus will eventually make up the majority of the population over time.
Natural selection is an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution, which states that animals acquire traits through usage or inaction. For instance, if the giraffe's neck gets longer through stretching to reach for prey and its offspring will inherit a more long neck. 에볼루션 룰렛 in neck size between generations will increase until the giraffe is no longer able to reproduce with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of one gene are distributed randomly in a group. At some point, one will reach fixation (become so common that it is unable to be removed by natural selection) and other alleles will fall to lower frequency. In extreme cases this, it leads to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small number of people it could result in the complete elimination of the recessive gene. This is called a bottleneck effect, and it is typical of evolutionary process that takes place when a lot of individuals migrate to form a new population.
A phenotypic bottleneck may happen when the survivors of a catastrophe, such as an epidemic or a massive hunt, are confined in a limited area. The survivors will carry an allele that is dominant and will have the same phenotype. This could be caused by earthquakes, war, or even plagues. Regardless of the cause the genetically distinct population that remains is prone to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a departure from expected values due to differences in fitness. They provide a well-known example of twins that are genetically identical, share the exact same phenotype but one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could play a crucial part in the evolution of an organism. It's not the only method of evolution. The most common alternative is to use a process known as natural selection, where phenotypic variation in the population is maintained through mutation and migration.
Stephens argues that there is a major difference between treating drift as a force or a cause and treating other causes of evolution such as mutation, selection, and migration as forces or causes. He claims that a causal mechanism account of drift allows us to distinguish it from the other forces, and that this distinction is vital. 에볼루션 슬롯 argues further that drift has both direction, i.e., it tends to eliminate heterozygosity. It also has a size that is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is often called "Lamarckism" and it states that simple organisms develop into more complex organisms through the inheritance of characteristics that result from an organism's natural activities, use and disuse. Lamarckism can be illustrated by a giraffe extending its neck to reach higher branches in the trees. This would cause giraffes to give their longer necks to offspring, which then become taller.
Lamarck the French zoologist, presented an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. According to 에볼루션 사이트 , living creatures evolved from inanimate matter through a series of gradual steps. Lamarck was not the only one to suggest that this might be the case but his reputation is widely regarded as having given the subject its first broad and comprehensive treatment.
The prevailing story is that Lamarckism became a rival to Charles Darwin's theory of evolutionary natural selection, and that the two theories battled out in the 19th century. Darwinism ultimately won, leading to what biologists refer to as the Modern Synthesis. The theory argues that acquired characteristics can be inherited, and instead suggests that organisms evolve by the symbiosis of environmental factors, like natural selection.
Although Lamarck believed in the concept of inheritance through acquired characters and his contemporaries also spoke of this idea, it was never a central element in any of their evolutionary theorizing. This is due in part to the fact that it was never validated scientifically.
It has been more than 200 years since the birth of Lamarck, and in the age genomics there is a growing evidence-based body of evidence to support the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more often epigenetic inheritance. This is a version that is just as valid as the popular Neodarwinian model.
Evolution by Adaptation
One of the most popular misconceptions about evolution is its being driven by a struggle for survival. This notion is not true and overlooks other forces that drive evolution. The fight for survival can be more precisely described as a fight to survive within a particular environment, which may involve not only other organisms, but also the physical environment itself.
To understand how evolution functions it is important to think about what adaptation is. It is a feature that allows a living thing to survive in its environment and reproduce. It can be a physical structure like fur or feathers. Or it can be a characteristic of behavior such as moving towards shade during the heat, or moving out to avoid the cold at night.
The capacity of an organism to draw energy from its environment and interact with other organisms as well as their physical environments is essential to its survival. The organism must have the right genes to generate offspring, and it must be able to find enough food and other resources. Furthermore, the organism needs to be capable of reproducing in a way that is optimally within its environmental niche.
These elements, along with gene flow and mutations can result in changes in the proportion of different alleles within the gene pool of a population. This shift in the frequency of alleles could lead to the development of new traits, and eventually, new species in the course of time.
Many of the characteristics we admire in animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, fur or feathers for insulation long legs to run away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires attention to the distinction between behavioral and physiological traits.
Physiological adaptations, such as the thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to seek out friends or to move to shade in hot weather, aren't. It is important to note that lack of planning does not cause an adaptation. Inability to think about the effects of a behavior even if it seems to be rational, could cause it to be unadaptive.