What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to develop over time. This includes the evolution of new species and the change in appearance of existing species.
Many examples have been given of this, such as different kinds of stickleback fish that can live in either salt or fresh water, and walking stick insect varieties that favor particular host plants. These are mostly reversible traits however, are not able to explain fundamental changes in body plans.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living organisms that inhabit our planet for many centuries. Charles Darwin's natural selection is the best-established explanation. This process occurs when those who are better adapted have more success in reproduction and survival than those who are less well-adapted. Over time, the population of well-adapted individuals grows and eventually creates an entirely new species.
Natural selection is an ongoing process and involves the interaction of three factors: variation, reproduction and inheritance. Mutation and sexual reproduction increase genetic diversity in an animal species. Inheritance refers the transmission of genetic characteristics, which includes both dominant and recessive genes, to their offspring. Reproduction is the process of generating fertile, viable offspring. This can be achieved via sexual or asexual methods.
All of these elements have to be in equilibrium for natural selection to occur. For example the case where a dominant allele at a gene causes an organism to survive and reproduce more frequently than the recessive allele the dominant allele will be more prominent in the population. However, if the allele confers a disadvantage in survival or reduces fertility, it will disappear from the population. The process is self-reinforced, which means that an organism with a beneficial characteristic can reproduce and survive longer than an individual with a maladaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and endure, is the higher number of offspring it produces. Individuals with favorable traits, like having a long neck in Giraffes, or the bright white patterns on male peacocks, are more likely than others to survive and reproduce which eventually leads to them becoming the majority.
Natural selection only affects populations, not individuals. This is an important distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics through use or neglect. If a giraffe expands its neck in order to catch prey and the neck grows longer, then its offspring will inherit this trait. The length difference between generations will continue until the giraffe's neck becomes too long to no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when the alleles of one gene are distributed randomly in a group. Eventually, only one will be fixed (become common enough that it can no longer be eliminated through natural selection), and the rest of the alleles will drop in frequency. This can result in an allele that is dominant in the extreme. The other alleles are essentially eliminated and heterozygosity has diminished to a minimum. In a small number of people it could result in the complete elimination of recessive gene. This is known as the bottleneck effect and is typical of an evolutionary process that occurs whenever the number of individuals migrate to form a group.
A phenotypic bottleneck could occur when survivors of a disaster like an epidemic or mass hunting event, are condensed into a small area. The surviving individuals are likely to be homozygous for the dominant allele, which means that they will all have the same phenotype and will therefore have the same fitness characteristics. This situation might be the result of a war, earthquake, or even a plague. Whatever the reason the genetically distinct group that is left might be susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They cite the famous example of twins that are genetically identical and share the same phenotype. However, one is struck by lightning and dies, but the other continues to reproduce.
This kind of drift could play a significant role in the evolution of an organism. However, it is not the only method to progress. 무료에볼루션 is a process known as natural selection, where the phenotypic diversity of the population is maintained through mutation and migration.
Stephens argues that there is a significant distinction between treating drift as a force or as a cause and considering other causes of evolution such as mutation, selection and migration as causes or causes. He argues that a causal-process account of drift allows us distinguish it from other forces and this distinction is crucial. He further argues that drift has both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by population size.
Evolution by 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 is often referred to as "Lamarckism" and it states that simple organisms grow into more complex organisms through the inherited characteristics that are a result of the organism's natural actions use and misuse. Lamarckism is typically illustrated with the image of a giraffe extending its neck to reach the higher branches in the trees. This could cause the necks of giraffes that are longer to be passed to their offspring, who would then become taller.
Lamarck was a French Zoologist. In his opening lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th May 1802, he introduced an original idea that fundamentally challenged the conventional wisdom about organic transformation. According to Lamarck, living creatures evolved from inanimate material through a series of gradual steps. Lamarck was not the first to propose this but he was thought of as the first to offer the subject a comprehensive and general explanation.
The popular narrative is that Lamarckism grew into a rival to Charles Darwin's theory of evolution by natural selection and that the two theories battled it out in the 19th century. Darwinism ultimately prevailed and led to what biologists call the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead argues that organisms evolve through the selective influence of environmental factors, such as Natural Selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed on to future generations. However, this idea was never a major part of any of their theories on evolution. This is partly because it was never scientifically validated.
It's been over 200 years since the birth of Lamarck, and in the age genomics there is a growing evidence-based body of evidence to support the heritability acquired characteristics. This is referred to as "neo Lamarckism", or more often epigenetic inheritance. It is a variant of evolution that is just as valid as the more popular Neo-Darwinian theory.
Evolution through the process of adaptation
One of the most widespread 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 determine the rate of evolution. The fight for survival can be more accurately described as a struggle to survive in a particular environment. This can include not just other organisms but also the physical environment.
To understand how evolution operates it is beneficial to think about what adaptation is. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce in its environment. It can be a physiological feature, such as feathers or fur or a behavior like moving to the shade during hot weather or stepping out at night to avoid the cold.
An organism's survival depends on its ability to extract energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism needs to have the right genes to generate offspring, and it must be able to access enough food and other resources. The organism must be able to reproduce itself at an amount that is appropriate for its specific niche.
These factors, in conjunction with mutations and gene flow can cause a shift in the proportion of different alleles within the gene pool of a population. As 에볼루션 무료 바카라 , this shift in allele frequency can result in the emergence of new traits, and eventually new species.
A lot of the traits we admire in animals and plants are adaptations. For instance lung or gills that extract oxygen from air, fur and feathers as insulation and long legs to get away from predators, and camouflage to hide. To understand the concept of adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physiological traits like large gills and thick fur are physical traits. The behavioral adaptations aren't like the tendency of animals to seek out companionship or move into the shade during hot temperatures. It is also important to remember that a lack of planning does not cause an adaptation. Failure to consider the consequences of a decision, even if it appears to be rational, may cause it to be unadaptive.