What is Free Evolution?
Free evolution is the notion that natural processes can lead to the development of organisms over time. This includes the appearance and growth of new species.
Many examples have been given of this, such as different kinds of stickleback fish that can be found in salt or fresh water, as well as walking stick insect varieties that are attracted to specific host plants. These typically reversible traits do not explain the fundamental changes in the body's basic plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is an enigma that has fascinated scientists for centuries. Charles Darwin's natural selection is the most well-known explanation. This process occurs when people who are more well-adapted have more success in reproduction and survival 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 is characterized by the interaction of three factors: variation, inheritance and reproduction. Sexual reproduction and mutation increase genetic diversity in the species. Inheritance refers to the transmission of a person’s genetic characteristics, which includes recessive and dominant genes to their offspring. Reproduction is the process of creating fertile, viable offspring. This can be done via sexual or asexual methods.
Natural selection only occurs when all these elements are in harmony. For instance, if an allele that is dominant at a gene can cause an organism to live and reproduce more often than the recessive one, the dominant allele will become more prominent within the population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will be eliminated. The process is self-reinforced, meaning that an organism with a beneficial trait can reproduce and survive longer than an individual with an unadaptive trait. The more offspring an organism produces, the greater its fitness, which is measured by its ability to reproduce and survive. Individuals with favorable traits, like a longer neck in giraffes or bright white colors in male peacocks, are more likely to be able to survive and create offspring, which means they will make up the majority of the population in the future.
Natural selection only acts on populations, not on individual organisms. This is an important distinction from the Lamarckian theory of evolution which claims that animals acquire characteristics through use or neglect. For instance, if a animal's neck is lengthened by stretching to reach for prey, its offspring will inherit a more long neck. The differences in neck size between generations will increase until the giraffe becomes unable to reproduce with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from one gene are distributed randomly within a population. At some point, one will reach fixation (become so widespread that it cannot be eliminated through natural selection), while the other alleles drop to lower frequencies. In 에볼루션 바카라 무료체험 , it leads to one allele dominance. The other alleles are eliminated, and heterozygosity decreases to zero. In a small group, this could result in the complete elimination of the recessive gene. This is known as the bottleneck effect and is typical of an evolutionary process that occurs whenever the number of individuals migrate to form a group.
A phenotypic 'bottleneck' can also occur when the survivors of a disaster such as an outbreak or mass hunting event are concentrated in a small area. The survivors will be largely homozygous for the dominant allele, which means that they will all have the same phenotype and consequently 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 prone to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected values due to differences in fitness. They cite a famous instance of twins who are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift can play a crucial role in the evolution of an organism. It's not the only method of evolution. Natural selection is the primary alternative, where mutations and migration keep phenotypic diversity within a population.
Stephens claims that there is a significant difference between treating the phenomenon of drift as a force or cause, and treating other causes such as migration and selection mutation as causes and forces. Stephens claims that a causal process model of drift allows us to distinguish it from other forces and this distinction is crucial. He further argues that drift is a directional force: that is, it tends to eliminate heterozygosity, and that it also has a magnitude, that is determined by population size.
Evolution through Lamarckism
When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, often referred to as “Lamarckism”, states that simple organisms develop into more complex organisms through inheriting characteristics that result from the use and abuse of an organism. Lamarckism is typically illustrated by an image of a giraffe extending its neck to reach higher up in the trees. This could result in giraffes passing on their longer necks to their offspring, which then grow even taller.
Lamarck, a French Zoologist from France, presented 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 Lamarck, living creatures evolved from inanimate materials through a series of gradual steps. Lamarck was not the only one to suggest that this might be the case but he is widely seen as having given the subject its first broad and comprehensive analysis.
The popular narrative is that Lamarckism was an opponent to Charles Darwin's theory of evolution by natural selection and that the two theories battled each other in the 19th century. Darwinism ultimately prevailed which led to what biologists call the Modern Synthesis. This theory denies the possibility that acquired traits can be inherited, and instead argues that organisms evolve through the action of environmental factors, including natural selection.
While Lamarck believed in the concept of inheritance by acquired characters and his contemporaries paid lip-service to this notion but it was not a major feature 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 year since Lamarck's birth, and in the age genomics, there is a growing body of evidence that supports the heritability of acquired traits. This is often called "neo-Lamarckism" or, more frequently, epigenetic inheritance. It is a version of evolution that is as relevant as the more popular neo-Darwinian model.
Evolution through Adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle for survival. This is a false assumption and ignores other forces driving evolution. The fight for survival is more accurately described as a struggle to survive in a particular environment. This can include not just other organisms but also the physical surroundings themselves.
Understanding the concept of adaptation is crucial to understand evolution. It is a feature that allows a living thing to survive in its environment and reproduce. It can be a physical structure, such as feathers or fur. Or it can be a behavior trait such as moving into the shade during hot weather, or coming out to avoid the cold at night.
The survival of an organism depends on its ability to extract energy from the environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes to produce offspring and be able find enough food and resources. The organism should be able to reproduce at an amount that is appropriate for its niche.
These factors, along with mutation and gene flow, lead to an alteration in the percentage 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 novel traits and eventually new species in the course of time.
Many of the features that we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, fur or feathers for insulation and long legs for running away from predators, and camouflage for hiding. To understand adaptation it is crucial to discern between physiological and behavioral traits.
Physiological adaptations, like thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the tendency to seek out friends or to move to 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, failure to think about the consequences of a decision can render it unadaptive even though it may appear to be reasonable or even essential.