What is Free Evolution?
Free evolution is the notion that the natural processes that organisms go through can lead them to evolve over time. This includes the appearance and growth 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 favor specific host plants. These mostly reversible traits permutations do not explain the fundamental changes in the basic body plan.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living creatures that live on our planet for centuries. The most widely accepted explanation is Charles Darwin's natural selection process, an evolutionary process that is triggered when more well-adapted individuals live longer and reproduce more effectively than those who are less well-adapted. As time passes, a group of well-adapted individuals increases and eventually creates a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity of a species. Inheritance is the passing of a person's genetic traits to their offspring, which includes both dominant and recessive alleles. Reproduction is the production of viable, fertile offspring, which includes both sexual and asexual methods.
Natural selection can only occur when all these elements are in balance. For example, if a dominant allele at a gene allows an organism to live and reproduce more frequently than the recessive allele, the dominant allele will become more prominent within the population. However, if the allele confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. The process is self-reinforcing, meaning that an organism with a beneficial trait is more likely to survive and reproduce than an individual with a maladaptive characteristic. The more offspring an organism can produce, the greater its fitness, which is measured by its capacity to reproduce itself and survive. Individuals with favorable traits, like having a long neck in Giraffes, or the bright white patterns on male peacocks are more likely than others to reproduce and survive, which will eventually lead to them becoming the majority.
Natural selection is an aspect of populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution, which states that animals acquire traits through use or neglect. For instance, if a animal's neck is lengthened by reaching out to catch prey and its offspring will inherit a larger neck. The difference in neck length 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 be at different frequencies in a group by chance events. At some point, one will reach fixation (become so widespread that it cannot be eliminated through natural selection), while other alleles will fall to lower frequency. This could lead to an allele that is dominant in the extreme. The other alleles have been essentially eliminated and heterozygosity has diminished to a minimum. In a small number of people this could result in the complete elimination of the recessive allele. Such a scenario would be called a bottleneck effect, and it is typical of the kind of evolutionary process when a lot of individuals migrate to form a new population.
A phenotypic bottleneck may also occur when the survivors of a disaster like an outbreak or mass hunt incident are concentrated in a small area. The survivors will carry an allele that is dominant and will have the same phenotype. This could be caused by war, earthquakes or even plagues. Whatever the reason the genetically distinct population that remains is prone to genetic drift.
Walsh Lewens and Ariew utilize Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any departure from the expected values for differences in fitness. They provide the famous case of twins who are genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, but the other lives to reproduce.
This type of drift is crucial in the evolution of the species. But, it's not the only method to progress. The most common alternative is to use a process known as natural selection, where the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens claims that there is a major difference between treating the phenomenon of drift as a force or as a cause and treating other causes of evolution like mutation, selection and migration as causes or causes. Stephens claims that a causal process account of drift allows us distinguish it from other forces and that this differentiation is crucial. He also claims that drift is a directional force: 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 frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, also referred to as “Lamarckism” which means that simple organisms transform into more complex organisms by inheriting characteristics that are a product of the organism's use and misuse. Lamarckism is typically illustrated with an image of a giraffe extending its neck longer to reach higher up in the trees. This causes the necks of giraffes that are longer to be passed onto their offspring who would then grow even taller.
에볼루션 무료체험 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. In his opinion living things evolved from inanimate matter through an escalating series of steps. Lamarck wasn't the first to make this claim, but he was widely considered to be the first to offer the subject a comprehensive and general overview.
The predominant story is that Charles Darwin's theory of natural selection and Lamarckism were competing in the 19th Century. Darwinism ultimately won and led to what biologists call the Modern Synthesis. The theory argues that acquired traits can be passed down and instead argues that organisms evolve through the selective influence of environmental factors, including Natural Selection.
Lamarck and his contemporaries supported 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's been more than 200 years since Lamarck was born and, in the age of genomics there is a huge body of evidence supporting the heritability of acquired characteristics. It is sometimes referred to as "neo-Lamarckism" or, more often epigenetic inheritance. It is a version of evolution that is just as relevant as the more popular Neo-Darwinian theory.
Evolution by Adaptation
One of the most common misconceptions about evolution is that it is driven by a type of struggle for survival. This view is inaccurate and ignores other forces driving evolution. The fight for survival is better described as a fight to survive in a particular environment. This may be a challenge for not just other living things but also the physical environment.
To understand how evolution functions it is important to understand what is adaptation. It refers to a specific characteristic that allows an organism to live and reproduce in its environment. It can be a physical structure like fur or feathers. Or it can be a characteristic of behavior such as moving to the shade during the heat, or escaping the cold at night.
The survival of an organism is dependent on its ability to extract energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes to create offspring and to be able to access enough food and resources. In addition, the organism should be capable of reproducing at a high rate within its niche.
These elements, along with mutations and gene flow can cause an alteration in the ratio of different alleles within a population’s gene pool. As time passes, this shift in allele frequency can result in the emergence of new traits and ultimately new species.
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. 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 traits. The behavioral adaptations aren't, such as the tendency of animals to seek companionship or retreat into shade during hot temperatures. Furthermore it is important to remember 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 make it unadaptive.