10 Tips For Free Evolution That Are Unexpected
What is Free Evolution?
Free evolution is the concept that natural processes can cause organisms to develop over time. This includes the development of new species and the alteration of the appearance of existing species.
A variety of examples have been provided of this, including different varieties of fish called sticklebacks 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 cannot explain fundamental changes to the basic body plan.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all the living creatures that live on our planet 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 community of well adapted individuals grows and eventually creates a new species.
Natural selection is a cyclical process that involves the interaction of three elements including inheritance, variation, and reproduction. Mutation and sexual reproduction increase genetic diversity in an animal species. Inheritance is the passing of a person's genetic characteristics to their offspring, which includes both recessive and dominant alleles. Reproduction is the production of fertile, viable offspring which includes both sexual and asexual methods.
All of these variables have to be in equilibrium for natural selection to occur. If, for instance the dominant gene allele makes an organism reproduce and survive more than the recessive gene, then the dominant allele is 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 meaning that an organism with an adaptive trait will survive and reproduce more quickly than those with a maladaptive trait. The more fit an organism is, measured by its ability reproduce and survive, is the greater number of offspring it will produce. People with good characteristics, like a longer neck in giraffes or bright white colors in male peacocks, are more likely to survive and produce offspring, and thus will become the majority of the population over time.
Natural selection only affects populations, not on individual organisms. This is a crucial distinction from the Lamarckian evolution theory that states that animals acquire traits either through usage or inaction. If a giraffe stretches its neck to reach prey, and the neck becomes longer, then its children will inherit this characteristic. The differences in neck length between generations will continue until the giraffe's neck becomes so long that it can no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of the same gene are randomly distributed in a population. At some point, one will reach fixation (become so common that it is unable to be eliminated through natural selection) and the other alleles drop to lower frequencies. In the extreme, this leads to dominance of a single allele. The other alleles have been essentially eliminated and heterozygosity has diminished to a minimum. In a small population it could lead to the complete elimination of recessive alleles. This scenario is called the bottleneck effect and is typical of an evolutionary process that occurs whenever a large number individuals migrate to form a group.
A phenotypic bottleneck can also occur when the survivors of a catastrophe like an outbreak or a mass hunting event are concentrated in an area of a limited size. The surviving individuals will be mostly homozygous for the dominant allele which means they will all have the same phenotype and therefore share the same fitness characteristics. This may be caused by conflict, earthquake, or even a plague. Regardless of the cause the genetically distinct population that remains could be prone to genetic drift.
Walsh, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any deviation from the expected values of different fitness levels. They give a famous example of twins that are genetically identical, share the exact same phenotype but one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift could be very important in the evolution of an entire species. This isn't the only method for evolution. The main alternative is a process known as natural selection, in which the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens claims that there is a significant distinction between treating drift as a force or a cause and treating other causes of evolution like selection, mutation and migration as forces or causes. He claims that a causal-process explanation of drift lets us separate 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 size, that is determined by population size.
Evolution by Lamarckism
Students of biology in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism which means that simple organisms transform into more complex organisms by adopting traits that are a product of the use and abuse of an organism. Lamarckism is typically illustrated with an image of a giraffe that extends its neck to reach leaves higher up in the trees. This could cause giraffes' longer necks to be passed on to their offspring who would 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 Lamarck, 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 being the one who gave the subject his first comprehensive and thorough treatment.
The predominant story is that Charles Darwin's theory of natural selection and Lamarckism were rivals in the 19th Century. Darwinism eventually won, leading to the development of what biologists now call the Modern Synthesis. This theory denies that traits acquired through evolution can be inherited, and instead argues that organisms evolve by the symbiosis of environmental factors, like natural selection.
While Lamarck supported the notion of inheritance by acquired characters and his contemporaries paid lip-service to this notion however, it was not a central element in any of their evolutionary theories. 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 field of genomics, there is an increasing evidence base that supports the heritability of acquired traits. This is often referred to as "neo-Lamarckism" or more frequently epigenetic inheritance. It is a variant of evolution that is just as valid as the more popular Neo-Darwinian model.
Evolution through the process of 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 drive evolution. The struggle for existence is more accurately described as a struggle to survive in a specific environment. This can include not only other organisms as well as the physical surroundings themselves.
To understand how evolution operates it is beneficial to consider what adaptation is. Adaptation is any feature that allows a living thing to survive in its environment and reproduce. It could be a physiological feature, like feathers or fur, or a behavioral trait such as a tendency to move into shade in the heat or leaving at night to avoid the cold.
The survival of an organism is dependent on its ability to draw energy from the environment and interact with other organisms and their physical environments. The organism should possess the right genes for producing offspring and to be able to access sufficient food and resources. The organism must also be able reproduce at an amount that is appropriate for its particular niche.
에볼루션 무료체험 , along with gene flow and mutations, can lead to changes in the proportion of different alleles in the gene pool of a population. This shift in the frequency of alleles can lead to the emergence of novel traits and eventually, new species as time passes.
Many of the features we appreciate in plants and animals are adaptations. For example lung or gills that extract oxygen from the air, fur and feathers as insulation long legs to run away from predators and camouflage to conceal. To understand adaptation, it is important to discern between physiological and behavioral characteristics.
Physical characteristics like large gills and thick fur are physical characteristics. The behavioral adaptations aren't an exception, for instance, the tendency of animals to seek companionship or to retreat into the shade during hot temperatures. In addition, it is important to understand that a lack of forethought does not make something an adaptation. A failure to consider the implications of a choice, even if it appears to be rational, could cause it to be unadaptive.