What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to develop over time. This includes the creation of new species and change in appearance of existing species.
Many examples have been given of this, including different kinds of stickleback fish that can live in fresh or salt water and walking stick insect varieties that prefer particular host plants. These typically reversible traits do not explain the fundamental changes in the basic body plan.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all 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 is triggered when more well-adapted individuals live longer and reproduce more successfully than those less well-adapted. Over time, a population of well-adapted individuals increases and eventually becomes a new species.
Natural selection is a process that is cyclical and involves the interaction of three factors: variation, reproduction and inheritance. Variation is caused by mutation and sexual reproduction both of which increase the genetic diversity within a species. Inheritance refers the transmission of genetic characteristics, which includes recessive and dominant genes, to their offspring. Reproduction is the production of fertile, viable offspring which includes both asexual and sexual methods.
All of these variables have to be in equilibrium for natural selection to occur. If, for example an allele of a dominant gene allows an organism to reproduce and last longer than the recessive gene allele The dominant allele will become more prevalent in a population. However, if the gene confers a disadvantage in survival or decreases fertility, it will be eliminated from the population. The process is self-reinforcing meaning that the organism with 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 can produce. 에볼루션 바카라 무료 with favorable traits, like longer necks in giraffes or bright white patterns of color in male peacocks are more likely to survive and have offspring, and thus will become the majority of the population in the future.
Natural selection is only a force for populations, not on individuals. This is a major distinction from the Lamarckian theory of evolution, which states that animals acquire characteristics by use or inactivity. If a giraffe extends its neck to catch prey, and the neck becomes longer, then its offspring will inherit this trait. The difference in neck size between generations will continue to grow until the giraffe is unable to breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, alleles at a gene may attain different frequencies in a population by chance events. In the end, one will attain fixation (become so common that it is unable to be removed by natural selection) and the other alleles drop to lower frequency. This can result in an allele that is dominant at the extreme. Other alleles have been basically eliminated and heterozygosity has diminished to a minimum. In a small number of people this could result in the total elimination of the recessive allele. This scenario is known as a bottleneck effect and it is typical of evolutionary process that takes place when a large amount of individuals move to form a new population.
A phenotypic bottleneck can also happen when the survivors of a disaster such as an epidemic or a mass hunt, are confined into a small area. The surviving individuals will be mostly homozygous for the dominant allele, which means that they will all share the same phenotype and will consequently share the same fitness characteristics. This situation could be caused by war, earthquakes, or even plagues. Whatever the reason, the genetically distinct population that is left might be prone to genetic drift.
Walsh Lewens, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any deviation from the expected values for different fitness levels. They cite a famous instance of twins who are genetically identical and have identical phenotypes and yet one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift could play a very important part in the evolution of an organism. It is not the only method for evolution. Natural selection is the main alternative, in which mutations and migration maintain the phenotypic diversity in the population.
Stephens claims that there is a vast distinction between treating drift as a force or cause, and treating other causes like selection mutation and migration as causes and forces. He argues that a causal-process account of drift allows us differentiate it from other forces, and this differentiation is crucial. He argues further that drift is both direction, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined based on population size.
Evolution through Lamarckism
When students in high school take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, often called "Lamarckism which means that simple organisms develop into more complex organisms through inheriting characteristics that result from the use and abuse of an organism. Lamarckism can be illustrated by an giraffe's neck stretching to reach higher levels of leaves in the trees. This would result in giraffes passing on their longer necks to offspring, who would then become taller.
Lamarck was a French Zoologist. In his lecture to begin his course on invertebrate zoology at the Museum of Natural History in Paris on the 17th of May in 1802, he presented an original idea that fundamentally challenged previous thinking about organic transformation. In his view living things evolved from inanimate matter via an escalating series of steps. Lamarck wasn't the only one to suggest this, but he was widely thought of as the first to offer the subject a comprehensive and general explanation.
The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were competing during the 19th century. Darwinism eventually triumphed, leading to the development of what biologists now call the Modern Synthesis. The theory denies that acquired characteristics can be passed down through generations and instead argues that organisms evolve through the selective action of environment elements, like Natural Selection.
Lamarck and his contemporaries believed in the idea that acquired characters could be passed down to the next generation. However, this concept was never a central part of any of their evolutionary theories. This is due to the fact that it was never scientifically validated.
It's been over 200 year since Lamarck's birth, and in the age genomics, there is a growing evidence-based body of evidence to support the heritability of acquired traits. It is sometimes referred to as "neo-Lamarckism" or, more commonly epigenetic inheritance. It is a version of evolution that is as relevant as the more popular Neo-Darwinian theory.
Evolution by adaptation
One of the most popular misconceptions about evolution is that it is being driven by a fight for survival. This view is inaccurate and ignores other forces driving evolution. The fight for survival is more accurately described as a struggle to survive in a certain environment. This could include not only other organisms, but also the physical environment itself.
To understand how evolution operates it is important to understand what is adaptation. The term "adaptation" refers to any characteristic that allows living organisms to survive in its environment and reproduce. It could be a physical feature, such as feathers or fur. Or it can be a behavior trait that allows you to move towards shade during hot weather, or escaping the cold at night.
An organism's survival depends on its ability to extract energy from the environment and to interact with other living organisms and their physical surroundings. The organism must have the right genes to create offspring, and it should be able to find sufficient food and other resources. In addition, the organism should be capable of reproducing in a way that is optimally within its niche.
These elements, in conjunction with gene flow and mutation result in a change in the proportion of alleles (different varieties of a particular gene) in a population's gene pool. The change in frequency of alleles could lead to the development of new traits, and eventually, new species as time passes.
Many of the characteristics we admire in animals and plants are adaptations. For instance the lungs or gills which draw oxygen from air, fur and feathers as insulation and long legs to get away from predators, and camouflage to hide. However, a proper understanding of adaptation requires a keen eye to the distinction between behavioral and physiological characteristics.
Physiological traits like the thick fur and gills are physical traits. The behavioral adaptations aren't like the tendency of animals to seek companionship or move into the shade during hot weather. It is also important to keep in mind that the absence of planning doesn't result in an adaptation. In fact, a failure to consider the consequences of a choice can render it ineffective, despite the fact that it might appear logical or even necessary.