What is Free Evolution?
Free evolution is the concept that the natural processes of organisms can lead them to evolve over time. This includes the emergence and development of new species.
This has been proven by many examples, including stickleback fish varieties that can be found in fresh or saltwater and walking stick insect types that prefer particular host plants. These reversible traits, however, cannot explain fundamental changes in body plans.
Evolution by Natural Selection
The evolution of the myriad living organisms on Earth is an enigma that has fascinated scientists for many centuries. Charles Darwin's natural selectivity is the most well-known explanation. This happens when people who are more well-adapted have more success in reproduction and survival than those who are less well-adapted. Over time, a population of well-adapted individuals expands and eventually forms a whole new species.
Natural selection is a cyclical process that involves the interaction of three factors including inheritance, variation, and reproduction. Sexual reproduction and mutations increase the genetic diversity of a species. Inheritance refers the transmission of a person’s genetic traits, including both dominant and recessive genes and their offspring. Reproduction is the production of fertile, viable offspring, which includes both sexual and asexual methods.
Natural selection can only occur when all of these factors are in harmony. For example when the dominant allele of a gene causes an organism to survive and reproduce more often than the recessive one, the dominant allele will become more common in the population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will go away. This process is self-reinforcing, which means that the organism with an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive trait. The more offspring an organism produces, the greater its fitness, which is measured by its capacity to reproduce itself and live. People with good characteristics, such as the long neck of Giraffes, or the bright white color patterns on male peacocks are more likely to others to reproduce and survive which eventually leads to them becoming the majority.
Natural selection is an aspect of populations and not on individuals. This is a crucial distinction from the Lamarckian theory of evolution that states that animals acquire traits either through use or lack of use. If a giraffe stretches its neck to catch prey, and the neck becomes longer, then the offspring will inherit this trait. The differences in neck size between generations will continue to grow until the giraffe is unable to reproduce with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles within a gene can attain different frequencies in a population due to random events. At some point, one will attain fixation (become so widespread that it cannot be eliminated by natural selection), while other alleles will fall to lower frequency. This can result in an allele that is dominant at the extreme. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small number of people, this could result in the complete elimination of the recessive gene. This scenario is called 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 can also occur when the survivors of a catastrophe such as an epidemic or mass hunt, are confined into a small area. The survivors will share a dominant allele and thus will have the same phenotype. This situation could be caused by earthquakes, war or even plagues. The genetically distinct population, if it is left vulnerable to genetic drift.
Walsh, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any departure from the expected values of different fitness levels. They provide a well-known example of twins that are genetically identical, share the exact same phenotype and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift can be vital to the evolution of an entire species. However, it is not the only method to progress. Natural selection is the primary alternative, in which mutations and migration maintain the phenotypic diversity in the population.
Stephens argues there is a vast difference between treating the phenomenon of drift as a force or cause, and considering other causes, such as migration and selection as causes and forces. He claims that a causal process explanation of drift allows us to distinguish it from the other forces, and that this distinction is essential. He also argues that drift has a direction, that is it tends to reduce heterozygosity, and that it also has a size, that is determined by the size of population.
Evolution by Lamarckism
Students of biology in high school are frequently 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 via the inheritance of traits that are a result of an organism's natural activities, use and disuse. Lamarckism is illustrated through a giraffe extending its neck to reach higher levels of leaves in the trees. This could cause the necks of giraffes that are longer to be passed on to their offspring who would grow taller.
Lamarck the French Zoologist, introduced an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According Lamarck, living organisms evolved from inanimate material by a series of gradual steps. Lamarck wasn't the first to make this claim but he was considered to be the first to give the subject a thorough and general treatment.
The most popular story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were rivals in the 19th Century. Darwinism ultimately prevailed, leading to what biologists refer to as the Modern Synthesis. The theory argues the possibility that acquired traits can be acquired through inheritance and instead suggests that organisms evolve through the selective action of environmental factors, including natural selection.
Lamarck and his contemporaries believed in the notion that acquired characters could be passed on to the next generation. However, this notion was never a major part of any of their theories about evolution. This is partly because it was never tested scientifically.
However, it has been more than 200 years since Lamarck was born and, in the age of genomics there is a huge amount of evidence that supports the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. It is a variant of evolution that is as valid as the more popular neo-Darwinian model.
Evolution through Adaptation
One of the most widespread misconceptions about evolution is that it is driven by a sort of struggle to survive. In fact, this view is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The fight for survival can be more accurately described as a struggle to survive within a particular environment, which can be a struggle that involves not only other organisms but also the physical environment.
Understanding the concept of adaptation is crucial to understand evolution. Adaptation refers to any particular feature that allows an organism to survive and reproduce within its environment. It can be a physical structure, like feathers or fur. It could also be a characteristic of behavior such as moving to the shade during the heat, or coming out to avoid the cold at night.
The survival of an organism is dependent on its ability to extract energy from the environment and interact with other organisms and their physical environments. The organism should possess the right genes to create offspring, and be able to find sufficient food and resources. In addition, the organism should be capable of reproducing itself at a high rate within its environment.
These factors, along with gene flow and mutation can result in an alteration in the percentage of alleles (different forms of a gene) in a population's gene pool. Over time, this change in allele frequencies can lead to the emergence of new traits and ultimately new species.
Many of the features we find appealing in animals and plants are adaptations. For example, lungs or gills that draw oxygen from air feathers and fur for insulation long legs to run away from predators and camouflage for hiding. However, 에볼루션바카라사이트 of adaptation requires paying attention to the distinction between the physiological and behavioral characteristics.
Physiological adaptations, such as thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to search for companions or to retreat to shade in hot weather, aren't. Additionally, it is important to note that lack of planning does not mean that something is an adaptation. Failure to consider the effects of a behavior, even if it appears to be rational, may make it inflexible.