What is Free Evolution?
Free evolution is the idea that the natural processes of living organisms can lead to their development over time. This includes the evolution of new species as well as the change in appearance of existing ones.
Numerous examples have been offered of this, including different varieties of fish called sticklebacks that can live in salt or fresh water, and walking stick insect varieties that are attracted to particular host plants. These reversible traits do not explain the fundamental changes in the body's basic plans.
Evolution through Natural Selection
The development of the myriad living organisms 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 those who are better adapted survive and reproduce more than those who are less well-adapted. Over time, a community of well-adapted individuals expands and eventually becomes a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity within 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. Reproduction is the process of creating viable, fertile offspring. This can be accomplished by both asexual or sexual methods.
Natural selection only occurs when all the factors are in equilibrium. If, for example, a dominant gene allele allows an organism to reproduce and live longer than the recessive allele, then the dominant allele becomes more prevalent in a group. If the allele confers a negative survival advantage or decreases the fertility of the population, it will disappear. The process is self reinforcing meaning that an organism with an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive feature. The more offspring an organism produces the better its fitness which is measured by its ability to reproduce and survive. People with good traits, such as a longer neck in giraffes or bright white color patterns in male peacocks are more likely to survive and produce offspring, and thus will eventually make up the majority of the population in the future.
Natural selection is an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics through use or disuse. If a giraffe extends its neck in order to catch prey and the neck grows larger, then its offspring will inherit this characteristic. The length difference between generations will persist until the giraffe's neck gets so long that it can no longer 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, only one of them will be fixed (become widespread enough to not longer be eliminated through natural selection) and the other alleles will drop in frequency. This could lead to dominance at the extreme. The other alleles are essentially eliminated and heterozygosity has decreased to zero. In a small population it could result in the complete elimination of the recessive gene. This scenario is called the bottleneck effect and is typical of the evolution process that occurs when an enormous number of individuals move to form a population.
A phenotypic bottleneck can also occur when the survivors of a catastrophe, such as an epidemic or a mass hunting event, are condensed into a small area. The survivors will carry an allele that is dominant and will share the same phenotype. This could be caused by earthquakes, war or even a plague. The genetically distinct population, if it remains vulnerable to genetic drift.
Walsh, Lewens, and Ariew employ Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from the expected values of differences in fitness. They cite a famous instance of twins who are genetically identical, share identical phenotypes and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift could be very important in the evolution of the species. But, it's not the only way to evolve. The most common alternative is a process known as natural selection, in which phenotypic variation in a population is maintained by mutation and migration.
Stephens argues there is a vast difference between treating the phenomenon of drift as an actual cause or force, and treating other causes such as migration and selection as forces and causes. He claims that a causal process explanation of drift permits us to differentiate it from the other forces, and that this distinction is crucial. He also claims that drift is a directional force: that is it tends to reduce heterozygosity. It also has a magnitude, that is determined by the size of population.
Evolution by Lamarckism
Students of biology in high school are often introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution is often called "Lamarckism" and it states that simple organisms grow into more complex organisms via the inheritance of characteristics that are a result of the organism's natural actions, use and disuse. Lamarckism is typically illustrated with an image of a giraffe that extends its neck to reach the higher branches in the trees. 에볼루션 게이밍 would result in giraffes passing on their longer necks to offspring, which then get taller.
Lamarck the French Zoologist from France, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. In his view, living things had evolved from inanimate matter via the gradual progression of events. 에볼루션 바카라 무료 was not the only one to suggest that this might be the case, but the general consensus is that he was the one being the one who gave the subject his first comprehensive and comprehensive analysis.
The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were competing in the 19th Century. Darwinism eventually prevailed and led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down through generations and instead argues that organisms evolve through the selective influence of environmental elements, like Natural Selection.
While Lamarck believed in the concept of inheritance by acquired characters and his contemporaries offered a few words about this idea, it was never a central element in any of their evolutionary theories. This is partly because it was never scientifically tested.
It's been more than 200 years since Lamarck was born and, in the age of genomics there is a vast amount of evidence that supports the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. It is a variant of evolution that is just as valid as the more well-known neo-Darwinian model.
Evolution by Adaptation
One of the most commonly-held misconceptions about evolution is being driven by a struggle for survival. In fact, this view is a misrepresentation of natural selection and ignores the other forces that are driving evolution. The struggle for survival is more accurately described as a struggle to survive within a particular environment, which can be a struggle that involves not only other organisms but also the physical environment.
To understand how evolution works, it is helpful to understand what is adaptation. It refers to a specific feature that allows an organism to live and reproduce in its environment. It could be a physiological feature, like feathers or fur or a behavioral characteristic like moving into shade in the heat or leaving at night to avoid the cold.
An organism's survival depends on its ability to obtain energy from the environment and to interact with other organisms and their physical environments. The organism needs to have the right genes to create offspring, and it should be able to locate enough food and other resources. The organism must also be able to reproduce at an amount that is appropriate for its particular niche.
These elements, in conjunction with gene flow and mutation can result in an alteration in the percentage of alleles (different varieties of a particular gene) in the gene pool of a population. This shift in the frequency of alleles can result in the emergence of new traits and eventually, new species over time.
Many of the features we appreciate in animals and plants are adaptations. For example the lungs or gills which draw oxygen from air, fur and feathers as insulation long legs to run away from predators and camouflage for hiding. To understand the concept of adaptation, it is important to distinguish between behavioral and physiological traits.
Physical traits such as large gills and thick fur are physical traits. Behavior adaptations aren't an exception, for instance, the tendency of animals to seek companionship or move into the shade in hot weather. Furthermore it is important to remember that a lack of thought is not a reason to make something an adaptation. Inability to think about the consequences of a decision even if it appears to be rational, may make it unadaptive.