What is Free Evolution?
Free evolution is the concept that the natural processes of organisms can lead them to evolve over time. This includes the appearance and development of new species.
Many examples have been given of this, such as different kinds of stickleback fish that can live in either fresh or salt water and walking stick insect varieties that prefer specific host plants. These reversible traits, however, cannot be the reason for fundamental changes in body plans.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all the living creatures that inhabit our planet for many centuries. The best-established explanation is that of Charles Darwin's natural selection, an evolutionary process that occurs when better-adapted individuals survive and reproduce more effectively than those less well adapted. Over time, a community of well-adapted individuals increases and eventually creates a new species.
Natural selection is a cyclical process that is characterized by the interaction of three factors that are inheritance, variation and reproduction. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity within the species. 에볼루션카지노 refers to the passing of a person's genetic traits to the offspring of that person that includes recessive and dominant alleles. Reproduction is the process of creating viable, fertile offspring. Related Homepag can be accomplished via sexual or asexual methods.
All of these elements have to be in equilibrium for natural selection to occur. For example when an allele that is dominant at the gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will become more prevalent in the population. If the allele confers a negative advantage to survival or reduces the fertility of the population, it will disappear. The process is self reinforcing, which means that an organism that has an adaptive characteristic will live and reproduce more quickly than those with a maladaptive feature. The more fit an organism is as measured by its capacity to reproduce and survive, is the more offspring it produces. People with good traits, like longer necks in giraffes and bright white patterns of color in male peacocks, are more likely to be able to survive and create offspring, so they will make up the majority of the population over time.
Natural selection only acts on populations, not individual organisms. This is a major distinction from the Lamarckian evolution theory that states that animals acquire traits either through the use or absence of use. If a giraffe stretches its neck in order to catch prey and the neck grows longer, then the offspring will inherit this trait. The difference in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, the alleles of a gene could be at different frequencies in a population due to random events. Eventually, one of them will attain fixation (become so common that it can no longer be eliminated by natural selection) and the other alleles drop to lower frequencies. In extreme cases this, it leads to dominance of a single allele. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small group it could result in the complete elimination the recessive gene. This scenario is known as a bottleneck effect and it is typical of the kind of evolutionary process that takes place when a large number of people migrate to form a new group.
A phenotypic bottleneck can also occur when the survivors of a disaster such as an outbreak or mass hunting event are confined to a small area. The survivors will have a dominant allele and thus will share the same phenotype. This situation might be caused by war, earthquake or even a disease. Whatever the reason the genetically distinct group that remains could be prone to genetic drift.
Walsh Lewens, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values of different fitness levels. They provide a well-known example of twins that are genetically identical, share identical phenotypes and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift could be crucial in the evolution of a species. However, it is not the only way to develop. The main alternative is a process called natural selection, where the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens claims that there is a big difference between treating the phenomenon of drift as a force, or a cause and treating other causes of evolution, such as mutation, selection and migration as forces or causes. He argues that a causal-process account of drift allows us differentiate it from other forces, and this distinction is crucial. He also argues that drift has both a direction, i.e., it tends to reduce heterozygosity. It also has a size, which is determined based on 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, often called "Lamarckism which means 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 with an image of a giraffe extending its neck longer to reach the higher branches in the trees. This process would cause giraffes to pass on their longer necks to their offspring, who then become taller.
Lamarck Lamarck, a French zoologist, 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 Lamarck, living things evolved from inanimate materials through a series gradual steps. Lamarck was not the only one to suggest that this could be the case, but his reputation is widely regarded as giving the subject its first broad and comprehensive analysis.
The prevailing story is that Lamarckism became an opponent to Charles Darwin's theory of evolution by natural selection, and both theories battled each other in the 19th century. Darwinism ultimately won and led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down and instead argues organisms evolve by the selective action of environment elements, like Natural Selection.
Although Lamarck supported the notion of inheritance through acquired characters and his contemporaries also paid lip-service to this notion however, it was not a central element in any of their evolutionary theorizing. This is partly because it was never scientifically validated.
However, it has 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 sometimes referred to as "neo-Lamarckism" or, more commonly, epigenetic inheritance. This is a version that is as reliable as the popular neodarwinian model.
Evolution by adaptation
One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. This view is inaccurate and overlooks the other forces that determine the rate of evolution. The fight for survival can be better described as a fight to survive in a particular environment. This could include not just other organisms but also the physical surroundings themselves.
To understand how evolution operates it is beneficial to understand what is adaptation. Adaptation refers to any particular characteristic that allows an organism to survive and reproduce within its environment. It could be a physical structure like feathers or fur. It could also be a trait of behavior such as moving to the shade during the heat, or escaping the cold at night.
The survival of an organism depends on its ability to obtain energy from the environment and to interact with other living organisms and their physical surroundings. The organism must have the right genes to produce offspring, and it must be able to locate sufficient food and other resources. Furthermore, the organism needs to be capable of reproducing at a high rate within its environmental niche.
These elements, along with mutations and gene flow can cause changes in the proportion of different alleles within the population's gene pool. This shift in the frequency of alleles could lead to the development of new traits, and eventually, new species over time.
Many of the features that we admire in animals and plants are adaptations, for example, lung or gills for removing oxygen from the air, feathers or fur to protect themselves 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 the physiological and behavioral characteristics.
Physiological adaptations, like thick fur or gills are physical characteristics, whereas behavioral adaptations, like the desire to find companions or to move into the shade in hot weather, aren't. Additionally it is important to note that a lack of thought is not a reason to make something an adaptation. In fact, failure to think about the implications of a decision can render it unadaptive despite the fact that it appears to be logical or even necessary.