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 development of new species and the alteration of the appearance of existing species.
This has been proven by numerous examples such as the stickleback fish species that can thrive in salt or fresh water, and walking stick insect types that have a preference for particular host plants. These mostly reversible traits permutations are not able to explain fundamental changes to the basic body plan.
Evolution by Natural Selection
The development of the myriad of living creatures on Earth is an enigma that has intrigued scientists for decades. Charles Darwin's natural selection theory is the best-established explanation. This process occurs when people who are more well-adapted survive and reproduce more than those who are less well-adapted. Over time, the population of well-adapted individuals becomes larger and eventually creates a new species.
Natural selection is an ongoing process that is characterized by the interaction of three elements: variation, inheritance and reproduction. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity of the species. Inheritance is the transfer of a person's genetic characteristics to his or her offspring that includes dominant and recessive alleles. Reproduction is the process of producing fertile, viable offspring. This can be achieved via sexual or asexual methods.
All of these factors have to be in equilibrium for natural selection to occur. If, for example an allele of a dominant gene makes an organism reproduce and survive more than the recessive gene, then the dominant allele is more common in a population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will be eliminated. The process is self-reinforced, meaning that a species that has a beneficial trait will survive and reproduce more than one with an unadaptive characteristic. The more fit an organism is as measured by its capacity to reproduce and endure, is the higher number of offspring it produces. People with good traits, like having a longer neck in giraffes, or bright white patterns of color in male peacocks, are more likely to survive and have offspring, which means they will make up the majority of the population over time.
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 traits through use or disuse. For example, if a animal's neck is lengthened by stretching to reach prey, its offspring will inherit a longer neck. The difference in neck size between generations will continue to increase until the giraffe is no longer able to reproduce with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles of a gene could attain different frequencies in a population through random events. Eventually, only one will be fixed (become widespread enough to not more be eliminated through natural selection), and the other alleles will drop in frequency. In the extreme it can lead to dominance of a single allele. The other alleles have been basically eliminated and heterozygosity has diminished to zero. In a small population, this could lead to the total elimination of recessive alleles. Such a scenario would be called a bottleneck effect, and it is typical of the kind of evolutionary process when a large amount of individuals migrate to form a new population.
A phenotypic bottleneck could occur when the survivors of a disaster like an epidemic or a massive hunt, are confined into a small area. The survivors will share a dominant allele and thus will have the same phenotype. This situation could be caused by war, earthquakes or even a plague. The genetically distinct population, if it is left susceptible to genetic drift.
Walsh, Lewens, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from the expected values of different fitness levels. They cite a famous example of twins that are genetically identical and have the exact same phenotype and yet one is struck by lightening and dies while the other lives and reproduces.
This type of drift is crucial in the evolution of the species. This isn't the only method of evolution. Natural selection is the main alternative, in which mutations and migration maintain the phenotypic diversity of the population.
Stephens asserts that there is a significant difference between treating drift as a force, or a cause and considering other causes of evolution such as selection, mutation and migration as causes or causes. He argues that a causal-process account of drift allows us separate it from other forces and this distinction is essential. He argues further that drift has direction, i.e., it tends to eliminate heterozygosity. It also has a size which is determined based on population size.
Evolution by Lamarckism
Students of biology in high school are frequently introduced to Jean-Baptiste Lamarck's (1744-1829) work. 에볼루션 카지노 of evolution is generally called "Lamarckism" and it asserts that simple organisms evolve into more complex organisms via the inheritance of characteristics that result from the natural activities of an organism, use and disuse. Lamarckism is typically illustrated by an image of a giraffe stretching its neck to reach leaves higher up in the trees. This could cause the longer necks of giraffes to be passed onto their offspring who would grow taller.
Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to him living things evolved from inanimate matter through the gradual progression of events. Lamarck wasn't the first to make this claim however he was widely considered to be the first to offer the subject a comprehensive and general explanation.
The prevailing story is that Lamarckism grew into a rival to Charles Darwin's theory of evolution through natural selection and that the two theories battled it out in the 19th century. Darwinism eventually prevailed which led to what biologists refer to as the Modern Synthesis. The theory argues that acquired traits can be passed down and instead, it claims that organisms evolve through the selective influence of environmental factors, such as 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 central part of any of their theories about evolution. This is due in part to the fact that it was never tested scientifically.
It has been more than 200 years since the birth of Lamarck and in the field of age genomics, there is a growing body of evidence that supports the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more generally epigenetic inheritance. This is a model that is as reliable as the popular neodarwinian model.
Evolution by adaptation
One of the most common misconceptions about evolution is being driven by a fight for survival. This notion is not true and ignores other forces driving evolution. The fight for survival can be more accurately described as a struggle to survive in a particular environment. This could include not just other organisms as well as the physical environment.
To understand how evolution functions it is beneficial to think about what adaptation is. Adaptation is any feature that allows a living thing to live in its environment and reproduce. It can be a physical structure, like fur or feathers. It could also be a behavior trait, like moving towards shade during hot weather, or escaping the cold at night.
The ability of an organism to extract energy from its environment and interact with other organisms as well as their physical environments is essential to its survival. The organism must possess the right genes to produce offspring and be able find enough food and resources. In addition, the organism should be able to reproduce itself at an optimal rate within its environment.
These elements, in conjunction with mutation and gene flow 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 novel traits and eventually, new species in the course of time.
Many of the characteristics we admire about animals and plants are adaptations, such as the lungs or gills that extract oxygen from the air, fur or feathers to protect themselves long legs to run away from predators, and camouflage to hide. However, a proper understanding of adaptation requires attention to the distinction between behavioral and physiological traits.
Physiological adaptations like thick fur or gills are physical traits, whereas behavioral adaptations, like the desire to find companions or to retreat into the shade in hot weather, aren't. It is important to note that insufficient planning does not cause an adaptation. Inability to think about the effects of a behavior, even if it appears to be rational, may make it inflexible.