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 appearance and growth of new species.
This has been proven by many examples of stickleback fish species that can live in fresh or saltwater and walking stick insect varieties that are apprehensive about particular host plants. These mostly reversible traits permutations cannot explain fundamental changes to the body's basic plans.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all the living creatures that live on our planet for ages. The most well-known explanation is that of Charles Darwin's natural selection, a process that occurs when better-adapted individuals survive and reproduce more effectively than those less well-adapted. Over time, the population of individuals who are well-adapted grows and eventually creates an entirely new species.
Natural selection is an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Sexual reproduction and mutation increase genetic diversity in the species. Inheritance refers to the passing of a person's genetic traits to his or her offspring, which includes both dominant and recessive alleles. weblink is the process of producing viable, fertile 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 allows an organism to reproduce and live longer than the recessive gene allele, then the dominant allele becomes more prevalent in a group. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will disappear. The process is self-reinforced, meaning that an organism with a beneficial trait is more likely to survive and reproduce than an individual with a maladaptive characteristic. The higher the level of fitness an organism has, measured by its ability reproduce and endure, is the higher number of offspring it can produce. Individuals with favorable traits, like having a long neck in giraffes, or bright white patterns on male peacocks are more likely than others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection is only an element in the population and not on individuals. original site is a significant distinction from the Lamarckian theory of evolution which claims that animals acquire traits through use or disuse. If a giraffe extends its neck to catch prey, and the neck becomes longer, then its offspring will inherit this characteristic. The length difference between generations will continue until the neck of the giraffe becomes too long to not breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, alleles within a gene can be at different frequencies in a population due to random events. At some point, one will reach fixation (become so widespread that it can no longer be eliminated through natural selection) and the other alleles drop to lower frequency. This could lead to dominance at the extreme. Other alleles have been basically eliminated and heterozygosity has decreased to zero. In a small number of people this could lead to the complete elimination of 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 group.
A phenotypic bottleneck can also occur when survivors of a disaster, such as an epidemic or a mass hunt, are confined into a small area. The survivors are likely to be homozygous for the dominant allele which means that they will all have the same phenotype and will thus have the same fitness traits. 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, Walsh, and Ariew define drift as a departure from the expected values due to differences in fitness. They provide a well-known 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 could be crucial in the evolution of a species. It is not the only method of evolution. Natural selection is the most common alternative, in which mutations and migration maintain phenotypic diversity within a population.
Stephens asserts that there is a big difference between treating the phenomenon of drift as a force or as an underlying cause, and considering other causes of evolution like mutation, selection and migration as forces or causes. He argues that a causal-process explanation of drift lets us differentiate it from other forces and this differentiation is crucial. He further argues that drift is a directional force: that is it tends to reduce heterozygosity. It also has a specific magnitude that is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, commonly referred to as “Lamarckism” which means that simple organisms evolve into more complex organisms taking on traits that result from the organism's use and misuse. Lamarckism is usually illustrated with a picture of a giraffe stretching its neck further to reach higher up in the trees. This causes the longer necks of giraffes to be passed to their offspring, who would then become taller.
Lamarck was a French zoologist and, in his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced an original idea that fundamentally challenged the previous understanding of organic transformation. According to Lamarck, living creatures evolved from inanimate material through a series gradual steps. Lamarck was not the only one to suggest that this could be the case but he is widely seen as giving the subject its first general and thorough treatment.
The dominant story is that Charles Darwin's theory on natural selection and Lamarckism were competing in the 19th Century. Darwinism ultimately won, leading to what biologists call the Modern Synthesis. The theory argues the possibility that acquired traits can be inherited, and instead suggests that organisms evolve by the symbiosis of environmental factors, such as natural selection.
Lamarck and his contemporaries endorsed the notion that acquired characters could be passed on to the next generation. However, this concept was never a central part of any of their theories on evolution. 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 field of age genomics, there is a growing body of evidence that supports the heritability-acquired characteristics. This is sometimes called "neo-Lamarckism" or more frequently, epigenetic inheritance. This is a variant that is as reliable as the popular Neodarwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is that it is driven by a sort of struggle for survival. This notion is not true and overlooks 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 just other organisms as well as the physical environment itself.
To understand how evolution operates it is beneficial to think about what adaptation is. The term "adaptation" refers to any characteristic that allows living organisms to live in its environment and reproduce. It could be a physiological structure, such as feathers or fur or a behavioral characteristic such as a tendency to move to the shade during hot weather or stepping out at night to avoid the cold.
The capacity of a living thing to extract energy from its surroundings 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 find enough food and other resources. Furthermore, the organism needs to be able to reproduce itself at a high rate within its environment.
These factors, along with mutation and gene flow can result in a change in the proportion of alleles (different types of a gene) in the population's gene pool. Over time, this change in allele frequencies could result in the development of new traits, and eventually new species.
Many of the features that we admire in animals and plants are adaptations, like lung or gills for removing oxygen from the air, feathers or fur for insulation long legs to run away from predators, and camouflage to hide. However, a proper understanding of adaptation requires attention to the distinction between physiological and behavioral characteristics.
Physical traits such as the thick fur and gills are physical characteristics. Behavior adaptations aren't an exception, for instance, the tendency of animals to seek out companionship or retreat into shade during hot temperatures. In addition it is important to understand that a lack of thought is not a reason to make something an adaptation. Failure to consider the effects of a behavior even if it seems to be logical, can cause it to be unadaptive.