What is Free Evolution?
Free evolution is the idea that the natural processes that organisms go through can lead to their development over time. This includes the creation of new species and change in appearance of existing species.
This has been proven by many examples such as the stickleback fish species that can be found in saltwater or fresh water and walking stick insect species that are apprehensive about particular host plants. These are mostly reversible traits, however, cannot explain fundamental changes in basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all the living organisms that inhabit our planet for centuries. Charles Darwin's natural selection theory is the best-established explanation. This is because those who are better 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 forms a whole new species.
Natural selection is an ongoing process that is characterized by the interaction of three factors including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity within a species. Inheritance is the term used to describe the transmission of a person's 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 variables have to be in equilibrium to allow natural selection to take place. If, for example, a dominant gene allele causes an organism reproduce and live longer than the recessive allele, then the dominant allele is more prevalent in a population. If the allele confers a negative advantage to survival 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 far more effectively than those with a maladaptive feature. The more fit an organism is as measured by its capacity to reproduce and survive, is the greater number of offspring it can produce. People with good characteristics, such as having a long neck in the giraffe, or bright white patterns on male peacocks are more likely to others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection is a factor in populations and not on individuals. This is a major distinction from the Lamarckian evolution theory which holds that animals acquire traits through use or lack of use. If a giraffe expands its neck in order to catch prey and the neck grows longer, then the children will inherit this characteristic. The length difference between generations will persist until the giraffe's neck gets so long that it can not breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, the alleles of a gene could attain different frequencies in a population due to random events. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated by natural selection), and the other alleles will decrease in frequency. This can lead to an allele that is dominant in the extreme. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small number of people this could lead to the complete elimination the recessive gene. This scenario is called a bottleneck effect, and it is typical of evolutionary process that takes place when a large number of individuals migrate to form a new population.
A phenotypic bottleneck can also occur when the survivors of a disaster such as an outbreak or mass hunting event are confined to the same area. The surviving individuals will be largely homozygous for the dominant allele, which means that they will all share the same phenotype and thus have the same fitness traits. This may be the result of a war, an earthquake, or even a plague. Whatever the reason the genetically distinct group that is left might be prone to genetic drift.
Walsh Lewens, Lewens, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They provide the famous case of twins who are both genetically identical and share the same phenotype, but one is struck by lightning and dies, but the other is able to reproduce.
This kind of drift can play a significant part in the evolution of an organism. It's not the only method for evolution. Natural selection is the primary alternative, where mutations and migration keep phenotypic diversity within a population.
Stephens asserts that there is a huge difference between treating the phenomenon of drift as an agent or cause and treating other causes such as migration and selection mutation as forces and causes. 무료에볼루션 argues that a causal-process model of drift allows us to distinguish it from other forces, and this distinction is crucial. He argues further that drift has both a direction, i.e., it tends to reduce heterozygosity. It also has a size which is determined based on population size.
Evolution by 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, also referred to as "Lamarckism, states that simple organisms develop into more complex organisms by inheriting characteristics that are a product of the organism's use and misuse. Lamarckism can be illustrated by an giraffe's neck stretching to reach higher leaves in the trees. This would cause the longer necks of giraffes to be passed onto their offspring who would then grow even taller.
Lamarck, a French zoologist, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged traditional thinking about organic transformation. In his view, living things had evolved from inanimate matter via the gradual progression of events. Lamarck wasn't the only one to make this claim but he was thought of as the first to provide the subject a comprehensive and general explanation.
The popular narrative is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection, and that the two theories fought each other in the 19th century. Darwinism ultimately won, leading to what biologists refer to as the Modern Synthesis. The theory argues that acquired traits can be passed down and instead, it claims that organisms evolve through the selective influence of environmental factors, including Natural Selection.
While Lamarck supported the notion of inheritance by acquired characters and his contemporaries also paid lip-service to this notion but it was not a major feature in any of their evolutionary theories. This is partly due to the fact that it was never validated scientifically.
But it is now more than 200 years since Lamarck was born and in the age of genomics, there is a large amount of evidence to support the heritability of acquired characteristics. This is referred to as "neo Lamarckism", or more often epigenetic inheritance. This is a version that is just as valid as the popular neodarwinian model.
Evolution by adaptation
One of the most commonly-held misconceptions about evolution is being driven by a fight for survival. In reality, this notion is inaccurate and overlooks the other forces that drive evolution. The fight for survival is better described as a fight to survive in a specific environment. This can be a challenge for not just other living things as well as the physical surroundings themselves.
Understanding the concept of adaptation is crucial to comprehend evolution. Adaptation is any feature that allows a living thing to survive in its environment and reproduce. It can be a physiological feature, like feathers or fur or a behavioral characteristic, such as moving into the shade in hot weather or coming out at night to avoid cold.
The capacity of a living thing to extract energy from its surroundings and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism must have the right genes to create offspring, and be able to find sufficient food and resources. The organism should be able to reproduce itself at the rate that is suitable for its niche.
These factors, together with gene flow and mutation can result in changes in the ratio of alleles (different forms of a gene) in the population's gene pool. This shift in the frequency of alleles could lead to the development of new traits and eventually, new species over time.
Many of the features that we admire about animals and plants are adaptations, like lungs or gills to extract 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 a keen eye to the distinction between physiological and behavioral traits.
Physiological adaptations like thick fur or gills, are physical traits, while behavioral adaptations, like the tendency to search for companions or to move to shade in hot weather, are not. more.. is important to note that the absence of planning doesn't cause an adaptation. In fact, failing to consider the consequences of a behavior can make it unadaptive, despite the fact that it might appear logical or even necessary.