What is Free Evolution?
Free evolution is the concept that the natural processes of living organisms can lead them to evolve over time. This includes the emergence and development of new species.
Many examples have been given of this, including various varieties of stickleback fish that can live in salt or fresh water, as well as walking stick insect varieties that favor particular host plants. These are mostly reversible traits however, are not able to explain fundamental changes in body plans.
Evolution by Natural Selection
The evolution of the myriad living organisms on Earth is an enigma that has intrigued scientists for many centuries. Charles Darwin's natural selectivity is the best-established explanation. This process occurs when people who are more well-adapted survive and reproduce more than those who are less well-adapted. Over time, the population of well-adapted individuals becomes larger and eventually develops into an entirely new species.
Natural selection is an ongoing process and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity within an animal species. 에볼루션 카지노 is the term used to describe the transmission of 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 elements must be in balance to allow natural selection to take place. For example the case where the dominant allele of one gene can cause an organism to live and reproduce more frequently than the recessive allele the dominant allele will become more common in the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will go away. The process is self reinforcing which means that the organism with an adaptive trait will live and reproduce more quickly than one with a maladaptive characteristic. The more offspring an organism can produce the more fit it is, which is measured by its ability to reproduce and survive. People with desirable characteristics, like having a longer neck in giraffes or bright white colors in male peacocks are more likely to survive and have offspring, which means they will make up the majority of the population in the future.
Natural selection only acts on populations, not individuals. This is a significant distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics by use or inactivity. For example, if a Giraffe's neck grows longer due to stretching to reach for prey its offspring will inherit a longer neck. The difference in neck size between generations will continue to increase until the giraffe is no longer able to reproduce with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles of a gene could reach different frequencies in a population through random events. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated through natural selection), and the rest of the alleles will drop in frequency. In the extreme it can lead to a single allele dominance. The other alleles are virtually eliminated and heterozygosity diminished to a minimum. In a small number of people, this could lead to the total elimination of recessive alleles. This scenario is called the bottleneck effect and is typical of the evolution process that occurs when an enormous number of individuals move to form a population.
A phenotypic bottleneck may occur when survivors of a catastrophe, such as an epidemic or a massive hunting event, are concentrated in a limited area. The survivors are likely to be homozygous for the dominant allele, which means they will all share the same phenotype and will thus share the same fitness characteristics. This situation might be caused by war, earthquake or even a cholera outbreak. Regardless of the cause, the genetically distinct population that remains could be susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values of differences in fitness. They cite a famous instance of twins who are genetically identical, have the exact same phenotype and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift can play a significant role in the evolution of an organism. It is not the only method for evolution. Natural selection is the most common alternative, in which mutations and migration maintain the phenotypic diversity in a population.
Stephens asserts that there is a huge distinction between treating drift as an actual cause or force, and treating other causes such as migration and selection mutation as forces and causes. He argues that a causal-process model of drift allows us to differentiate it from other forces and that this differentiation is crucial. He also claims that drift has a direction, that is, it tends to eliminate heterozygosity. It also has a magnitude, that is determined by the size of population.
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 is often known as "Lamarckism" and it states that simple organisms grow into more complex organisms via the inheritance of characteristics that are a result of the natural activities of an organism use and misuse. Lamarckism can be demonstrated by the giraffe's neck being extended to reach higher branches in the trees. This could cause the longer necks of giraffes to be passed to their offspring, who would then grow even taller.
Lamarck was a French zoologist and, in his inaugural lecture for his course on invertebrate zoology at the Museum of Natural History in Paris on the 17th May 1802, he introduced an original idea that fundamentally challenged the conventional wisdom about organic transformation. According Lamarck, living organisms evolved from inanimate matter through a series gradual steps. Lamarck wasn't the only one to suggest this but he was thought of as the first to provide the subject a thorough and general treatment.
The popular narrative is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection, and both theories battled each other in the 19th century. Darwinism ultimately prevailed, leading to what biologists refer to as the Modern Synthesis. The theory argues that acquired traits can be passed down through generations and instead argues organisms evolve by the selective influence of environmental factors, such as Natural Selection.
While Lamarck believed in the concept of inheritance by acquired characters and his contemporaries offered a few words about this idea, it was never a major feature in any of their theories about evolution. This is due in part to the fact that it was never tested scientifically.
It has been more than 200 year since Lamarck's birth and in the field of age genomics there is a growing body of evidence that supports the heritability-acquired characteristics. This is sometimes referred to as "neo-Lamarckism" or more frequently epigenetic inheritance. This is a version that is as reliable as the popular neodarwinian model.
Evolution through adaptation
One of the most common misconceptions about evolution is that it is a result of a kind of struggle to survive. This view is inaccurate and overlooks the other forces that are driving evolution. The struggle for survival is more accurately described as a struggle to survive in a specific environment, which may be a struggle that involves not only other organisms, but as well the physical environment.
Understanding the concept of adaptation is crucial to understand evolution. It refers to a specific feature that allows an organism to survive and reproduce in its environment. It could be a physical feature, such as feathers or fur. Or it can be a behavior trait such as moving towards shade during hot weather or coming out to avoid the cold at night.
The ability of an organism to extract energy from its environment and interact with other organisms, as well as their physical environments is essential to its survival. The organism needs to have the right genes to produce offspring, and it must be able to access sufficient food and other resources. The organism should be able to reproduce itself at the rate that is suitable for its niche.
These factors, together with mutation and gene flow, lead to a change in the proportion of alleles (different forms of a gene) in a population's gene pool. As time passes, this shift in allele frequency can result in the development of new traits and eventually new species.
A lot of the traits we admire about animals and plants are adaptations, like lungs or gills to extract oxygen from the air, feathers or fur to provide insulation long legs to run away from predators and camouflage for hiding. However, a proper understanding of adaptation requires a keen eye to the distinction between behavioral and physiological traits.
Physiological adaptations, such as the thick fur or gills are physical traits, while behavioral adaptations, like the desire to find companions or to retreat to the shade during hot weather, are not. It is also important to note that lack of planning does not result in an adaptation. In fact, failure to think about the consequences of a behavior can make it unadaptable, despite the fact that it may appear to be logical or even necessary.