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 of stickleback fish species that can be found in fresh or saltwater and walking stick insect varieties that prefer specific host plants. These reversible traits do not explain the fundamental changes in the basic body plan.
Evolution by Natural Selection
The evolution of the myriad living organisms on Earth is an enigma that has fascinated scientists for many centuries. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when people who are more well-adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, the population of individuals who are well-adapted grows and eventually develops into a new species.
Natural selection is an ongoing process that involves the interaction of three elements: variation, inheritance and reproduction. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity of the species. Inheritance refers to the passing of a person's genetic traits to the offspring of that person which includes both dominant and recessive alleles. Reproduction is the process of generating viable, fertile offspring. This can be done through sexual or asexual methods.
All of these variables must be in harmony for natural selection to occur. For example the case where a dominant allele at the gene can cause an organism to live and reproduce more frequently than the recessive one, the dominant allele will be more prevalent within the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. The process is self reinforcing which means that an organism that has an adaptive trait will live and reproduce much more than those with a maladaptive trait. The greater an organism's fitness which is measured by its ability to reproduce and survive, is the more offspring it will produce. Individuals with favorable traits, like having a longer neck in giraffes or bright white colors in male peacocks are more likely survive and produce offspring, and thus will make up the majority of the population over time.
Natural selection is an element in the population and not on individuals. This is a crucial distinction from the Lamarckian evolution theory which holds that animals acquire traits due to use or lack of use. If a giraffe extends its neck to reach prey, and the neck becomes larger, then its children will inherit this characteristic. The differences in neck length between generations will continue until the giraffe's neck becomes too long to no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when the alleles of the same gene are randomly distributed in a population. Eventually, only one will be fixed (become widespread enough to not more be eliminated through natural selection) and the rest of the alleles will diminish in frequency. In the extreme it can lead to a single allele dominance. The other alleles are eliminated, and heterozygosity falls to zero. In a small number of people, this could result in the complete elimination of recessive gene. This is known as the bottleneck effect and is typical of the evolutionary process that occurs when an enormous number of individuals move to form a group.
A phenotypic bottleneck could occur when survivors of a catastrophe, such as an epidemic or mass hunt, are confined into a small area. The survivors will carry an dominant allele, and will share the same phenotype. This situation could be caused by war, earthquakes, or even plagues. Regardless of the cause the genetically distinct group that remains is susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected values due to differences in fitness. They cite a famous instance of twins who are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could be vital to the evolution of the species. However, it's not the only method to evolve. Natural selection is the main alternative, in which mutations and migration maintain the phenotypic diversity in a population.
Stephens argues there is a significant difference between treating drift like an actual cause or force, and treating other causes like selection mutation and migration as forces and causes. He argues that a causal process account of drift allows us to distinguish it from the other forces, and this distinction is essential. He argues further that drift has both direction, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined by population size.
Evolution through Lamarckism
Students of biology in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, commonly referred to as "Lamarckism is based on the idea that simple organisms develop into more complex organisms inheriting characteristics that are a product of the organism's use and misuse. Lamarckism is typically illustrated by a picture of a giraffe stretching its neck to reach higher up in the trees. This would cause the necks of giraffes that are longer to be passed onto their offspring who would then become taller.
Lamarck the French zoologist, presented an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to Lamarck, living creatures evolved from inanimate material through a series of gradual steps. Lamarck was not the only one to suggest that this might be the case, but the general consensus is that he was the one having given the subject its first broad and thorough treatment.
The predominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th Century. Darwinism ultimately won and led to what biologists call the Modern Synthesis. This theory denies the possibility that acquired traits can be acquired through inheritance and instead, it argues that organisms develop by the symbiosis of environmental factors, including natural selection.
Although Lamarck believed in the concept of inheritance through acquired characters and his contemporaries paid lip-service to this notion, it was never a major feature in any of their evolutionary theorizing. This is largely due to the fact that it was never validated scientifically.
It has been more than 200 year since Lamarck's birth and in the field of genomics there is a growing evidence-based body of evidence to support the heritability acquired characteristics. This is sometimes referred to as "neo-Lamarckism" or more commonly epigenetic inheritance. It is a form of evolution that is as valid as the more well-known Neo-Darwinian model.
Evolution through adaptation
One of the most widespread misconceptions about evolution is that it is driven by a type of struggle to survive. 에볼루션게이밍 misrepresents natural selection and ignores the other forces that drive evolution. The fight for survival is better described as a struggle to survive in a certain environment. This could be a challenge for not just other living things but also the physical surroundings themselves.
To understand how evolution works it is important to think about what adaptation is. Adaptation is any feature that allows living organisms to survive in its environment and reproduce. It could be a physiological structure like feathers or fur or a behavioral characteristic like moving into the shade in hot weather or stepping out at night to avoid the cold.
The survival of an organism is dependent on its ability to obtain energy from the surrounding environment and interact with other organisms and their physical environments. The organism must possess the right genes to create offspring, and it should be able to access sufficient food and other resources. Furthermore, the organism needs to be able to reproduce itself at an optimal rate within its environment.
These factors, together with gene flow and mutations can result in a shift in the proportion of different alleles within a population’s gene pool. Over time, this change in allele frequency can result in the development of new traits and ultimately new species.
Many of the characteristics we admire about animals and plants are adaptations, like lungs or gills to extract oxygen from the air, fur or feathers to protect themselves and long legs for running away from predators, and camouflage for hiding. However, a thorough understanding of adaptation requires a keen eye to the distinction between behavioral and physiological characteristics.
Physiological adaptations like thick fur or gills, are physical characteristics, whereas behavioral adaptations, such as the tendency to search for companions or to move to shade in hot weather, are not. It is also important to keep in mind that insufficient planning does not cause an adaptation. In fact, failing to consider the consequences of a decision can render it unadaptive, despite the fact that it may appear to be sensible or even necessary.