What is Free Evolution?
Free evolution is the concept that the natural processes of organisms can lead to their development over time. This includes the evolution of new species as well as the change in appearance of existing species.
A variety of examples have been provided of this, including various varieties of stickleback fish that can be found in salt or fresh water, as well as walking stick insect varieties that prefer specific host plants. These typically reversible traits are not able to explain fundamental changes to basic body plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is a mystery that has intrigued scientists for many centuries. Charles Darwin's natural selectivity is the most well-known explanation. This is because individuals who are better-adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, a group of well-adapted individuals expands and eventually creates a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity of an animal species. Inheritance refers to the transmission of a person's genetic characteristics, which includes recessive and dominant genes, to their offspring. Reproduction is the generation of fertile, viable offspring, which includes both sexual and asexual methods.
All of these elements must be in balance to allow natural selection to take place. For example the case where an allele that is dominant at a gene allows an organism to live and reproduce more frequently than the recessive allele the dominant allele will be more prominent in the population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will disappear. The process is self-reinforced, meaning that an organism with a beneficial trait will survive and reproduce more than an individual with an inadaptive characteristic. The more fit an organism is which is measured by its ability to reproduce and survive, is the greater number of offspring it produces. People with desirable characteristics, such as having a long neck in Giraffes, or the bright white patterns on male peacocks are more likely to others to live and reproduce and eventually lead to them becoming the majority.
Natural selection is an element in the population and not on individuals. This is a major distinction from the Lamarckian theory of evolution which argues that animals acquire traits by use or inactivity. If a giraffe stretches its neck to reach prey and the neck grows larger, then its offspring will inherit this characteristic. The differences in neck size between generations will increase until the giraffe becomes unable to reproduce with other giraffes.
Evolution by Genetic Drift
In the process of genetic drift, alleles at a gene may attain different frequencies in a group through random events. Eventually, one of them will attain fixation (become so common that it cannot be removed by natural selection) and the other alleles drop to lower frequency. In extreme cases this, it leads to one allele dominance. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small number of people it could result in the complete elimination the recessive gene. This is known as the bottleneck effect. It is typical of the evolution process that occurs when the number of individuals migrate to form a population.
A phenotypic bottleneck could happen when the survivors of a catastrophe, such as an epidemic or a massive hunting event, are concentrated into a small area. The survivors will carry an allele that is dominant and will have the same phenotype. This situation could be caused by earthquakes, war or even a plague. The genetically distinct population, if it is left, could be susceptible to genetic drift.
Walsh Lewens and Ariew use Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from expected values for different fitness levels. They cite a famous example of twins that are genetically identical and have identical phenotypes, and yet one is struck by lightening and dies while the other lives and reproduces.
This type of drift can play a crucial part in the evolution of an organism. But, it's not the only method to progress. The main alternative is to use a process known as natural selection, in which phenotypic variation in an individual is maintained through mutation and migration.
Stephens claims that there is a major distinction between treating drift as a force, or an underlying cause, and treating other causes of evolution like mutation, selection and migration as causes or causes. He claims that a causal process explanation of drift allows us to distinguish it from other forces, and that this distinction is crucial. He further argues that drift is a directional force: that is it tends to eliminate heterozygosity. He also claims that it also has a magnitude, that is determined by the size of the population.
Evolution through Lamarckism
In high school, students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is commonly known as "Lamarckism" and it asserts that simple organisms evolve into more complex organisms by the inheritance of traits which result from an organism's natural activities usage, use and disuse. Lamarckism is typically illustrated with an image of a giraffe extending its neck further to reach the higher branches in the trees. This would cause the longer necks of giraffes to be passed to their offspring, who would grow taller.
Lamarck Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. In his opinion, living things had evolved from inanimate matter through an escalating series of steps. Lamarck was not the first to make this claim however he was widely considered to be the first to provide the subject a thorough and general explanation.
The popular narrative is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution by natural selection, and that the two theories fought it out in the 19th century. Darwinism eventually prevailed, leading to the development of what biologists today call the Modern Synthesis. The theory denies that acquired characteristics are passed down from generation to generation and instead argues organisms evolve by the influence of environment factors, including Natural Selection.
Although Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries paid lip-service to this notion but it was not an integral part of any of their evolutionary theorizing. This is partly because it was never tested scientifically.
It's been more than 200 year since Lamarck's birth and in the field of genomics, there is an increasing evidence base that supports the heritability of acquired traits. This is also known as "neo Lamarckism", or more generally epigenetic inheritance. It is a variant of evolution that is just as valid as the more popular neo-Darwinian model.
에볼루션 블랙잭 through Adaptation
One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. In fact, this view is inaccurate and overlooks the other forces that determine the rate of evolution. The fight for survival is more accurately described as a struggle to survive in a certain environment. This can include not only other organisms, but also the physical environment itself.
To understand how evolution works, it is helpful to understand what is adaptation. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce within its environment. It could be a physiological feature, such as fur or feathers, or a behavioral trait, such as moving into the shade in hot weather or stepping out at night to avoid the cold.
The capacity of an organism to extract energy from its surroundings and interact with other organisms, as well as their physical environments, is crucial to its survival. The organism must have the right genes to produce offspring, and it should be able to locate sufficient food and other resources. Furthermore, the organism needs to be able to reproduce itself in a way that is optimally within its environmental niche.
These factors, along with mutation and gene flow can result in an alteration in the percentage of alleles (different forms of a gene) in the gene pool of a population. This shift in the frequency of alleles can lead to the emergence of new traits, and eventually, new species as time passes.
A lot of the traits we admire about animals and plants are adaptations, like lungs or gills to extract oxygen from the air, fur or feathers to provide insulation and long legs for running away from predators and camouflage to hide. To understand adaptation, it is important to distinguish between behavioral and physiological characteristics.
Physiological adaptations like thick fur or gills are physical traits, whereas behavioral adaptations, such as the tendency to search for companions or to retreat to the shade during hot weather, are not. Furthermore, it is important to note that a lack of thought does not mean that something is an adaptation. A failure to consider the consequences of a decision even if it appears to be rational, could make it inflexible.