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 creation of new species and alteration of the appearance of existing species.
This is evident in numerous examples of stickleback fish species that can thrive in saltwater or fresh water and walking stick insect varieties that prefer specific host plants. These reversible traits cannot explain fundamental changes to the basic body plan.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all the living organisms that inhabit our planet for many centuries. Charles Darwin's natural selectivity is the best-established explanation. This is because those who are better adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, a population of well-adapted individuals expands and eventually forms a whole new species.
Natural selection is an ongoing process and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction both of which enhance the genetic diversity of an animal species. Inheritance refers the transmission of a person’s genetic traits, including recessive and dominant genes, to their offspring. Reproduction is the process of producing viable, fertile offspring, which includes both sexual and asexual methods.
All of these factors must be in balance for natural selection to occur. For instance when a dominant allele at one gene can cause an organism to live and reproduce more often than the recessive one, the dominant allele will become more prominent in the population. However, if the allele confers a disadvantage in survival or decreases fertility, it will be eliminated from the population. This process is self-reinforcing meaning that a species with a beneficial characteristic will survive and reproduce more than one with an inadaptive characteristic. The higher the level of fitness an organism has as measured by its capacity to reproduce and endure, is the higher number of offspring it produces. People with good traits, like a longer neck in giraffes and bright white color patterns in male peacocks, are more likely to survive and have offspring, and thus will eventually make up the majority of the population in the future.
Natural selection only affects populations, not individual organisms. This is an important distinction from the Lamarckian theory of evolution, which claims that animals acquire characteristics through use or disuse. For instance, if the Giraffe's neck grows longer due to stretching to reach prey and its offspring will inherit a more long neck. The length difference between generations will persist until the giraffe's neck becomes so long that it can no longer breed with other giraffes.
Evolution by Genetic Drift
In the process of genetic drift, alleles within a gene can attain different frequencies in a population by chance events. In the end, one will attain fixation (become so widespread that it cannot be eliminated by natural selection) and other alleles will fall to lower frequencies. In the extreme this, it leads to dominance of a single allele. Other alleles have been basically eliminated and heterozygosity has diminished to a minimum. In a small group this could lead to the complete elimination the recessive gene. This scenario is called a bottleneck effect, and it is typical of the kind of evolutionary process that occurs when a large amount of individuals move to form a new group.
A phenotypic bottleneck may also occur when the survivors of a disaster such as an outbreak or mass hunting event are confined to a small area. The remaining individuals will be largely homozygous for the dominant allele, which means they will all share the same phenotype, and consequently have the same fitness characteristics. This could be caused by earthquakes, war or even plagues. Regardless of the cause the genetically distinct population that is left might be susceptible to genetic drift.
Walsh Lewens and Ariew utilize Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any departure from the expected values of 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 is crucial in the evolution of a species. It's not the only method for evolution. Natural selection is the most common alternative, in which mutations and migration maintain the phenotypic diversity in a population.
Stephens claims that there is a vast difference between treating drift like a force or cause, and treating other causes such as migration and selection as causes and forces. Stephens claims that a causal process model of drift allows us to separate it from other forces and this distinction is crucial. He argues further that drift is both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by population size.
Evolution through Lamarckism
In high school, students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as “Lamarckism” which means that simple organisms evolve into more complex organisms through taking on traits that are a product of the organism's use and misuse. Lamarckism is usually illustrated with a picture of a giraffe that extends its neck further to reach the higher branches in the trees. This would cause the necks of giraffes that are longer to be passed on to their offspring who would grow taller.
Lamarck Lamarck, a French zoologist, 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. According to Lamarck, living creatures evolved from inanimate material by a series of gradual steps. Lamarck was not the first to propose this but he was regarded as the first to give the subject a thorough and general explanation.
The predominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were competing in the 19th century. Darwinism eventually prevailed and led to what biologists refer to as the Modern Synthesis. The theory denies that acquired characteristics can be passed down and instead argues organisms evolve by the selective influence of environmental elements, like Natural Selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed down to future generations. However, this concept was never a major part of any of their evolutionary theories. This is due to the fact that 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 vast amount of evidence that supports the possibility of inheritance of acquired traits. This is also known as "neo Lamarckism", or more generally epigenetic inheritance. This is a model that is just as valid as the popular Neodarwinian model.
Evolution by adaptation
One of the most popular misconceptions about evolution is that it is a result of a kind of struggle for survival. This view is inaccurate and overlooks the other forces that drive evolution. The fight for survival can be more precisely described as a fight to survive within a specific environment, which may include not just other organisms but also the physical environment.
To understand how evolution operates, it is helpful to think about what adaptation is. It is a feature that allows a living organism to survive in its environment and reproduce. It can be a physical structure such as feathers or fur. Or it can be a behavior trait that allows you to move into the shade during the heat, or escaping the cold at night.
An organism's survival depends on its ability to draw energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes for producing offspring, and be able to find enough food and resources. The organism must be able to reproduce at an amount that is appropriate for its niche.
These factors, in conjunction with mutations and gene flow, can lead to an alteration in the ratio of different alleles within a population’s gene pool. As time passes, this shift in allele frequencies could result in the development of new traits, and eventually new species.
Many of the characteristics we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, feathers or fur to protect themselves and long legs for running away from predators and camouflage to hide. To understand 에볼루션 블랙잭 is essential to differentiate between physiological and behavioral characteristics.
Physical traits such as thick fur and gills are physical traits. Behavioral adaptations are not an exception, for instance, the tendency of animals to seek companionship or to retreat into the shade in hot temperatures. Furthermore it is important to note that a lack of forethought does not make something an adaptation. In fact, a failure to consider the consequences of a behavior can make it unadaptive, despite the fact that it might appear sensible or even necessary.