What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can lead them to evolve over time. This includes the appearance and development of new species.
Numerous examples have been offered of this, including different kinds of stickleback fish that can live in salt or fresh water, and walking stick insect varieties that prefer particular host plants. These reversible traits, however, cannot be the reason for fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is a mystery that has fascinated scientists for centuries. Charles Darwin's natural selection is the most well-known explanation. This happens when individuals who are better-adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, a group of well adapted individuals grows and eventually creates a new species.
Natural selection is a cyclical process that is characterized by the interaction of three factors that are inheritance, variation and reproduction. Sexual reproduction and mutations increase the genetic diversity of the species. Inheritance is the term used to describe the transmission of a person’s genetic characteristics, which includes both dominant and recessive genes, to their offspring. Reproduction is the process of producing fertile, viable offspring, which includes both sexual and asexual methods.
All of these variables must be in harmony to allow natural selection to take place. For instance, if the dominant allele of one gene causes an organism to survive and reproduce more frequently than the recessive allele, the dominant allele will be more prevalent in the population. If the allele confers a negative advantage to survival or reduces the fertility of the population, it will go away. The process is self-reinforcing, which means that an organism with a beneficial characteristic is more likely to survive and reproduce than an individual with a maladaptive trait. The higher the level of fitness an organism has which is measured by its ability to reproduce and survive, is the greater number of offspring it produces. People with good traits, like a longer neck in giraffes, or bright white patterns of color in male peacocks, are more likely to survive and produce offspring, which means they will become the majority of the population in the future.
Natural selection only affects populations, not individuals. This is a major distinction from the Lamarckian evolution theory which holds that animals acquire traits either through the use or absence of use. If a giraffe stretches its neck to reach prey and its neck gets longer, then its offspring will inherit this trait. The difference in neck size between generations will increase until the giraffe is no longer able to breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles from one gene are distributed randomly in a group. At some point, only one of them will be fixed (become common enough to no longer be eliminated through natural selection) and the rest of the alleles will diminish in frequency. In extreme cases, this leads to a single allele dominance. Other alleles have been virtually eliminated and heterozygosity diminished to a minimum. In a small population this could result in the total elimination of recessive alleles. Such a scenario would be known as a bottleneck effect and it is typical of evolutionary process when a large number of individuals move to form a new group.
A phenotypic bottleneck could occur when the survivors of a disaster such as an epidemic or a mass hunt, are confined within a narrow area. The surviving individuals will be largely homozygous for the dominant allele, meaning that they all have the same phenotype and will consequently have the same fitness traits. This can be caused by war, earthquakes or even plagues. Whatever the reason the genetically distinct group that remains is prone to genetic drift.
Walsh Lewens, Lewens, and Ariew utilize Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They cite a famous instance of twins who are genetically identical, share identical phenotypes but one is struck by lightning and dies, while the other lives and reproduces.
This type of drift can play a crucial role in the evolution of an organism. It is not the only method for evolution. Natural selection is the primary alternative, where mutations and migration keep the phenotypic diversity of the population.
Stephens claims that there is a significant distinction between treating drift as an agent or cause and treating other causes like migration and selection mutation as causes and forces. Stephens claims that a causal process model of drift allows us to separate it from other forces and this distinction is crucial. He also claims that drift has a direction: that is it tends to reduce heterozygosity. It also has a size, that is determined by the size of the population.
Evolution by Lamarckism
Biology students in high school are often introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution is commonly called "Lamarckism" and it states that simple organisms develop into more complex organisms through the inheritance of traits that result from the organism's natural actions, use and disuse. Lamarckism is typically illustrated with an image of a giraffe that extends its neck to reach higher up in the trees. This could result in giraffes passing on their longer necks to offspring, which then grow even taller.
Lamarck, a French zoologist, presented an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. According Lamarck, living organisms evolved from inanimate matter through a series gradual steps. Lamarck was not the only one to suggest that this might be the case, but he is widely seen as giving the subject its first general and thorough treatment.
에볼루션 사이트 Evolution KR is that Charles Darwin's theory of natural selection and Lamarckism were rivals during the 19th century. Darwinism ultimately prevailed which led to what biologists refer to as the Modern Synthesis. The theory argues that acquired characteristics can be acquired through inheritance and instead suggests that organisms evolve through the action of environmental factors, including natural selection.
Lamarck and his contemporaries endorsed the notion that acquired characters could be passed down to the next generation. However, this idea was never a key element of any of their evolutionary theories. This is largely due to the fact that it was never validated scientifically.
It's been over 200 years since the birth of Lamarck and in the field of age genomics there is a growing evidence base that supports the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more generally epigenetic inheritance. It is a version of evolution that is just as valid as the more popular Neo-Darwinian model.
Evolution by the process of adaptation
One of the most widespread misconceptions about evolution is that it is driven by a type of struggle to survive. This is a false assumption and ignores other forces driving evolution. The fight for survival can be more precisely described as a fight to survive within a specific environment, which can be a struggle that involves not only other organisms, but also the physical environment itself.
Understanding the concept of adaptation is crucial to comprehend evolution. The term "adaptation" refers to any specific characteristic that allows an organism to live and reproduce in its environment. It could be a physiological feature, like feathers or fur or a behavior, such as moving into the shade in hot weather or stepping out at night to avoid cold.
The capacity of an organism to draw energy from its environment and interact with other organisms, as well as their physical environments is essential to its survival. The organism must have the right genes to generate offspring, and it should be able to locate enough food and other resources. Furthermore, the organism needs to be capable of reproducing itself at a high rate within its environment.
These elements, in conjunction with gene flow and mutation can result in an alteration in the percentage of alleles (different forms of a gene) in the population's gene pool. This shift in the frequency of alleles can lead to the emergence of new traits and eventually, new species over time.
Many of the characteristics we admire about animals and plants are adaptations, for example, lung or gills for removing oxygen from the air, feathers or fur to protect themselves long legs to run away from predators and camouflage to hide. However, a thorough understanding of adaptation requires paying attention to the distinction between physiological and behavioral characteristics.
Physical characteristics like thick fur and gills are physical traits. The behavioral adaptations aren't an exception, for instance, the tendency of animals to seek out companionship or to retreat into the shade during hot weather. In addition it is important to understand that lack of planning is not a reason to make something an adaptation. Inability to think about the implications of a choice, even if it appears to be logical, can make it unadaptive.