What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to develop over time. This includes the development of new species as well as the alteration of the appearance of existing species.
A variety of examples have been provided of this, including various varieties of stickleback fish that can live in fresh or salt water and walking stick insect varieties that are attracted to particular host plants. These mostly reversible trait permutations can't, however, be the reason for fundamental changes in body plans.
Evolution through Natural Selection
The development of the myriad living creatures on Earth is an enigma that has intrigued scientists for decades. Charles Darwin's natural selection is the best-established explanation. This process occurs 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 grows and eventually becomes a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Sexual reproduction and mutation increase the genetic diversity of the species. Inheritance is the term used to describe the transmission of genetic characteristics, which includes recessive and dominant genes to their offspring. Reproduction is the process of creating viable, fertile offspring. This can be done by both asexual or sexual methods.
All of these elements must be in harmony for natural selection to occur. For example when a dominant allele at a gene can cause an organism to live and reproduce more frequently than the recessive allele, the dominant allele will become more common within the population. However, if the gene confers an unfavorable survival advantage or reduces fertility, it will disappear from the population. This process is self-reinforcing meaning that an organism with a beneficial characteristic can reproduce and survive longer than one with a maladaptive characteristic. The more offspring an organism can produce the better its fitness that is determined by its ability to reproduce itself and live. People with good characteristics, like having a longer neck in giraffes and bright white color patterns in male peacocks, are more likely to survive and produce offspring, which means they will become the majority of the population over time.
Natural selection only affects populations, not individuals. This is a significant distinction from the Lamarckian evolution theory which holds that animals acquire traits through the use or absence of use. For instance, if a giraffe's neck gets longer through stretching to reach prey and its offspring will inherit a longer neck. The difference in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a population. 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 other alleles diminish in frequency. This can result in a dominant allele at the extreme. Other alleles have been basically eliminated and heterozygosity has been reduced to zero. In a small group this could result in the total elimination of recessive allele. This is known as the bottleneck effect and is typical of the evolution process that occurs when the number of individuals migrate to form a group.
A phenotypic bottleneck may occur when survivors of a disaster such as an epidemic or a mass hunt, are confined in a limited area. The survivors will carry an dominant allele, and will share the same phenotype. This could be the result of a war, earthquake, or even a plague. Regardless of the cause the genetically distinct population that remains is susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They give a famous instance of twins who 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 very important in the evolution of an entire species. However, it's not the only way to progress. Natural selection is the most common alternative, where mutations and migrations maintain the phenotypic diversity of the population.
Stephens claims that there is a vast distinction between treating drift as a force or cause, and treating other causes such as selection mutation and migration as forces and causes. He claims that a causal-process model of drift allows us to differentiate it from other forces, and this differentiation is crucial. He also argues that drift is a directional force: that is it tends to eliminate heterozygosity, and that it also has a specific magnitude that is determined by the size of population.
Evolution by Lamarckism
When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, also called "Lamarckism which means that simple organisms develop into more complex organisms taking on traits that result from an organism's use and disuse. 에볼루션 is typically illustrated with a picture of a giraffe stretching its neck further to reach leaves higher up in the trees. This would result in giraffes passing on their longer necks to offspring, who then grow even taller.
Lamarck was a French Zoologist. In his opening lecture for his course on invertebrate zoology at the Museum of Natural History in Paris on 17 May 1802, he presented an innovative concept that completely challenged the conventional wisdom about organic transformation. In his view, living things had evolved from inanimate matter via the gradual progression of events. Lamarck was not the only one to suggest that this could be the case, but he is widely seen as giving the subject his first comprehensive and comprehensive analysis.
The most popular story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolutionary natural selection and both theories battled each other in the 19th century. Darwinism ultimately prevailed which led to what biologists call the Modern Synthesis. The theory argues the possibility that acquired traits can be acquired through inheritance and instead argues 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 idea was never a major part of any of their evolutionary theories. This is partly due to the fact that it was never validated scientifically.
It's been over 200 year since Lamarck's birth and in the field of age genomics, there is an increasing body of evidence that supports the heritability of acquired traits. This is sometimes referred to as "neo-Lamarckism" or, more often epigenetic inheritance. This is a version that is as valid as the popular neodarwinian model.
Evolution by Adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle for survival. This is a false assumption and ignores other forces driving evolution. The fight for survival is more accurately described as a struggle to survive in a specific environment. This may include not just other organisms, but also the physical environment.
To understand how evolution works it is beneficial to understand what is adaptation. It is a feature that allows a living thing to live in its environment and reproduce. It can be a physical feature, like feathers or fur. It could also be a characteristic of behavior, like moving into the shade during the heat, or moving out to avoid the cold at night.
The capacity of an organism to extract energy from its environment and interact with other organisms, as well as their physical environments, is crucial to its survival. The organism needs to have the right genes to create offspring, and it must be able to access enough food and other resources. The organism should also be able to reproduce at a rate that is optimal for its particular niche.
These elements, along with mutations and gene flow can cause changes in the proportion of different alleles in a population’s gene pool. The change in frequency of alleles could lead to the development of novel traits and eventually new species in the course of time.
Many of the characteristics we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, fur or feathers for insulation long legs to run away from predators and camouflage to hide. To understand adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physical traits such as thick fur and gills are physical traits. Behavior adaptations aren't, such as the tendency of animals to seek out companionship or to retreat into the shade in hot weather. It is important to remember that a lack of planning does not result in an adaptation. In fact, failing to think about the consequences of a behavior can make it unadaptive even though it may appear to be reasonable or even essential.