What is Free Evolution?
Free evolution is the notion that the natural processes of living organisms can lead them to evolve over time. This includes the appearance and development of new species.
This is evident in numerous examples, including stickleback fish varieties that can be found in fresh or saltwater and walking stick insect species that have a preference for specific host plants. These are mostly reversible traits can't, however, be the reason for fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad of living creatures on Earth is a mystery that has fascinated scientists for decades. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when individuals who are better-adapted survive and reproduce more than those who are less well-adapted. Over time, a population 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 increase the genetic diversity within an animal species. Inheritance is the transfer of a person's genetic traits to his or her offspring that includes recessive and dominant alleles. Reproduction is the process of generating fertile, viable offspring. This can be done via sexual or asexual methods.
All of these elements have to be in equilibrium for natural selection to occur. If, for instance the dominant gene allele causes an organism reproduce and live longer than the recessive gene allele The dominant allele becomes more common in a population. If the allele confers a negative survival advantage or reduces the fertility of the population, it will go away. The process is self-reinforced, meaning that an organism with a beneficial characteristic can reproduce and survive longer than an individual with a maladaptive characteristic. The more fit an organism is, measured by its ability reproduce and endure, is the higher number of offspring it will produce. People with desirable characteristics, such as having a long neck in Giraffes, or the bright white patterns on male peacocks, are more likely than others to live and reproduce, which will eventually lead to them becoming the majority.
Natural selection is only a factor in populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution which states that animals acquire traits by use or inactivity. If a giraffe expands its neck in order to catch prey and the neck grows larger, then its children will inherit this characteristic. The difference in neck length between generations will persist until the giraffe's neck gets too long to no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a group. At some point, only one of them will be fixed (become widespread enough to not longer be eliminated by natural selection) and the rest of the alleles will drop in frequency. In extreme cases it can lead to one allele dominance. The other alleles are eliminated, and heterozygosity falls to zero. In a small number of people it could lead to the total elimination of recessive allele. This scenario is called the bottleneck effect. It is typical of an evolutionary process that occurs whenever the number of individuals migrate to form a population.
A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe like an outbreak or mass hunt event are confined to a small area. The survivors are likely to be homozygous for the dominant allele meaning that they all share the same phenotype and will thus have the same fitness traits. This situation could be caused by war, earthquakes or even plagues. The genetically distinct population, if it is left vulnerable to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a deviation from the expected value due to differences in fitness. They cite the famous example 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 can play a crucial role in the evolution of an organism. This isn't the only method for evolution. 에볼루션 무료체험 is to use a process known as natural selection, where phenotypic variation in an individual is maintained through mutation and migration.
Stephens argues there is a significant difference between treating drift like an actual cause or force, and treating other causes such as migration and selection mutation as forces and causes. He claims that a causal process explanation of drift allows us to distinguish it from these other forces, and that this distinction is crucial. He further argues that drift is a directional force: that is it tends to eliminate heterozygosity. He also claims that it also has a specific magnitude which is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is commonly referred to as "Lamarckism" and it states that simple organisms develop into more complex organisms through the inheritance of traits that are a result of the natural activities of an organism, use and disuse. Lamarckism is usually illustrated with an image of a giraffe that extends its neck further to reach leaves higher up in the trees. This would cause giraffes to give their longer necks to their offspring, who would then grow even taller.
Lamarck was a French zoologist and, in his opening lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on 17 May 1802, he presented a groundbreaking concept that radically challenged the conventional wisdom about organic transformation. According to him living things evolved from inanimate matter through a series of gradual steps. Lamarck wasn't the only one to propose this, but he was widely thought of as the first to provide the subject a comprehensive and general overview.
The dominant story is that Charles Darwin's theory on natural selection and Lamarckism fought in the 19th Century. Darwinism eventually prevailed and led to the creation of what biologists now call the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be inherited and instead argues that organisms evolve through the selective action of environmental factors, like natural selection.
Although Lamarck believed in the concept of inheritance by acquired characters and his contemporaries spoke of this idea however, it was not a central element in any of their theories about evolution. This is partly because it was never tested 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. This is often referred to as "neo-Lamarckism" or, more commonly epigenetic inheritance. It is a variant of evolution that is as relevant as the more popular Neo-Darwinian model.
Evolution through the process of adaptation
One of the most widespread misconceptions about evolution is that it is driven by a sort of struggle to survive. 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 certain environment. This can include not just other organisms, but also the physical environment.
To understand how evolution works, it is helpful to think about what adaptation is. Adaptation refers to any particular characteristic that allows an organism to live and reproduce within its environment. It could be a physical structure, such as feathers or fur. Or it can be a characteristic of behavior, like moving into the shade during the heat, or moving out to avoid the cold at night.
The ability of a living thing to extract energy from its surroundings and interact with other organisms as well as their physical environment is essential to its survival. The organism needs to have the right genes to produce offspring, and it should be able to locate sufficient food and other resources. The organism should be able to reproduce at an amount that is appropriate for its specific niche.
에볼루션 게이밍 , along with mutation and gene flow can result in changes in the ratio of alleles (different forms of a gene) in the gene pool of a population. Over time, this change in allele frequencies could lead to the emergence of new traits, and eventually new species.
A lot of the traits we admire about animals and plants are adaptations, such as lungs or gills to extract oxygen from the air, feathers or fur to protect themselves long legs to run away from predators, and camouflage for hiding. However, a proper understanding of adaptation requires paying attention to the distinction between the physiological and behavioral traits.
Physiological adaptations, such as thick fur or gills, are physical traits, whereas behavioral adaptations, like the tendency to seek out companions or to retreat into the shade in hot weather, aren't. In addition it is important to note that a lack of thought does not make something an adaptation. A failure to consider the implications of a choice even if it seems to be rational, may cause it to be unadaptive.