What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can lead them to evolve over time. This includes the evolution of new species and the transformation of the appearance of existing ones.
This has been proven by numerous examples, including stickleback fish varieties that can live in fresh or saltwater and walking stick insect species that have a preference for specific host plants. These typically reversible traits are not able to explain fundamental changes to the basic body plan.
Evolution by Natural Selection
Scientists have been fascinated by the development of all living creatures that inhabit our planet for centuries. The best-established explanation is Charles Darwin's natural selection process, which occurs when better-adapted individuals survive and reproduce more successfully than those that are less well-adapted. Over time, the population of well-adapted individuals becomes larger and eventually forms an entirely 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 an animal species. Inheritance is the passing of a person's genetic characteristics to their offspring that includes recessive and dominant alleles. Reproduction is the generation of fertile, viable offspring, which includes both sexual and asexual methods.
All of these variables must be in harmony to allow natural selection to take place. For instance, if an allele that is dominant at a gene can cause an organism to live and reproduce more frequently than the recessive allele the dominant allele will become more prominent within the population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will be eliminated. The process is self-reinforced, meaning that a species with a beneficial trait is more likely to survive and reproduce than an individual with a maladaptive characteristic. The more offspring an organism produces the more fit it is that is determined by its capacity to reproduce itself and survive. People with desirable characteristics, like having a longer neck in giraffes or bright white color patterns in male peacocks are more likely to be able to survive and create offspring, which means they will eventually make up the majority of the population over time.
Natural selection only acts on populations, not on individual organisms. This is a significant distinction from the Lamarckian evolution theory, which states that animals acquire traits due to the use or absence of use. For instance, if the animal's neck is lengthened by reaching out to catch prey its offspring will inherit a longer neck. The differences in neck size between generations will continue to increase until the giraffe is unable to reproduce with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from one gene are distributed randomly in a population. At some point, one will reach fixation (become so widespread that it is unable to be removed through natural selection), while other alleles fall to lower frequencies. In extreme cases it can lead to a single allele dominance. The other alleles have been essentially eliminated and heterozygosity has been reduced to a minimum. In a small group, this could result in the complete elimination of recessive gene. This is 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 may occur when survivors of a disaster such as an epidemic or mass hunting event, are condensed within a narrow area. The surviving individuals will be mostly homozygous for the dominant allele, meaning that they all have the same phenotype and will therefore have the same fitness characteristics. This situation could be caused by earthquakes, war or even a plague. The genetically distinct population, if it remains, could be susceptible to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a departure from expected values due to differences in fitness. They cite a famous example of twins that are genetically identical and have identical phenotypes but one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift can play a very important role in the evolution of an organism. It is not the only method for evolution. The main alternative is a process called natural selection, where the phenotypic diversity of the population is maintained through mutation and migration.
Stephens claims that there is a vast difference between treating drift like an actual cause or force, and considering other causes, such as migration and selection mutation as forces and causes. Stephens claims that a causal process explanation of drift lets us separate it from other forces and this differentiation is crucial. He also argues that drift has both direction, i.e., it tends to reduce heterozygosity. It also has a size which is determined by the size of the population.
Evolution by Lamarckism
Biology students in high school are often introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution, commonly called "Lamarckism, states that simple organisms transform into more complex organisms by adopting traits that result from the use and abuse of an organism. Lamarckism is usually illustrated with an image of a giraffe extending its neck longer to reach higher up in the trees. This process would cause giraffes to give their longer necks to their offspring, who would then grow even taller.
Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According to him living things had evolved from inanimate matter through the gradual progression of events. Lamarck wasn't the only one to propose this, but he was widely considered to be the first to provide the subject a thorough and general explanation.
The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th century. Darwinism eventually prevailed and led to the development of what biologists today call the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be inherited, and instead suggests that organisms evolve through the action of environmental factors, such as natural selection.
Although Lamarck endorsed the idea of inheritance through acquired characters and his contemporaries spoke of this idea, it was never a central element in any of their theories about evolution. This is due to the fact that it was never tested scientifically.
However, it has 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 known as "neo Lamarckism", or more commonly epigenetic inheritance. This is a variant that is 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. In reality, this notion is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The fight for survival can be more accurately described as a struggle to survive within a particular environment, which can be a struggle that involves not only other organisms, but as well the physical environment.
To understand how evolution works it is beneficial to think about what adaptation is. 에볼루션 슬롯게임 refers to any particular characteristic that allows an organism to live and reproduce within its environment. 에볼루션 슬롯게임 can be a physical feature, like fur or feathers. It could also be a characteristic of behavior that allows you to move to the shade during the heat, or coming out to avoid the cold at night.
The ability of a living thing to extract energy from its environment and interact with other organisms, as well as their physical environment is essential to its survival. The organism must have the right genes to generate offspring, and it must be able to find enough food and other resources. In addition, the organism should be able to reproduce itself at a high rate within its environmental niche.
These factors, together with mutation and gene flow can result in an alteration in the percentage of alleles (different varieties of a particular gene) in the population's gene pool. This shift in the frequency of alleles can result in the emergence of new traits, and eventually, new species as time passes.
Many of the characteristics we appreciate in plants and animals 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. However, a thorough understanding of adaptation requires a keen eye to the distinction between behavioral and physiological characteristics.
Physical traits such as large gills and thick fur are physical characteristics. The behavioral adaptations aren't like the tendency of animals to seek companionship or move into the shade in hot temperatures. It is also important to remember that a insufficient planning does not make an adaptation. In fact, failing to think about the consequences of a behavior can make it unadaptable despite the fact that it appears to be logical or even necessary.