Speak "Yes" To These 5 Free Evolution Tips
What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to evolve over time. This includes the evolution of new species and transformation of the appearance of existing ones.
This has been proven by numerous examples, including stickleback fish varieties that can thrive in salt or fresh water, 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 body's basic plans.
Evolution through Natural Selection
The development of the myriad of living creatures on Earth is an enigma that has fascinated scientists for centuries. The most well-known explanation is Charles Darwin's natural selection process, an evolutionary process that occurs when better-adapted individuals survive and reproduce more successfully than those who are less well-adapted. As time passes, a group of well adapted individuals grows and eventually creates a new species.
Natural selection is an ongoing process and involves the interaction of three factors including reproduction, variation and inheritance. Sexual reproduction and mutations increase the genetic diversity of the species. Inheritance is the transfer of a person's genetic traits to the offspring of that person that includes dominant and recessive alleles. Reproduction is the process of producing fertile, viable offspring which includes both asexual and sexual methods.
All of these elements must be in balance to allow natural selection to take place. For instance, if a dominant allele at the gene can cause an organism to live and reproduce more often than the recessive allele the dominant allele will become more prevalent in the population. However, if the allele confers a disadvantage in survival or reduces fertility, it will be eliminated from the population. This process is self-reinforcing meaning that an organism with an adaptive trait will survive and reproduce much more than one with a maladaptive characteristic. The greater an organism's fitness, measured by its ability reproduce and survive, is the greater number of offspring it produces. People with desirable traits, 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, so they will become the majority of the population in the future.
Natural selection only acts on populations, not on individuals. This is a major distinction from the Lamarckian evolution theory, which states that animals acquire traits either through use or lack of use. If a giraffe expands its neck to reach prey and the neck grows longer, then the offspring will inherit this characteristic. The difference in neck length between generations will continue until the giraffe's neck becomes too long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, the alleles of a gene could be at different frequencies in a population through random events. Eventually, only one will be fixed (become common enough to no longer be eliminated through natural selection), and the other alleles will diminish in frequency. This can result in a dominant allele in the extreme. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small number of people this could result in the total elimination of the recessive allele. This is known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs when a lot of people migrate to form a new population.
A phenotypic bottleneck may occur when the survivors of a catastrophe like an epidemic or a massive hunting event, are condensed into a small area. The survivors will share a dominant allele and thus will have the same phenotype. This situation might be the result of a war, earthquake or even a cholera outbreak. Whatever the reason, the genetically distinct population that remains is susceptible to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a deviation from expected values due to differences in fitness. They provide the famous case of twins who are both genetically identical and share the same phenotype, but one is struck by lightning and dies, while the other continues to reproduce.
This type of drift is crucial in the evolution of an entire species. It is not the only method for evolution. Natural selection is the main alternative, where mutations and migration keep the phenotypic diversity in the population.
Stephens claims that there is a big distinction between treating drift as a force or an underlying cause, and considering other causes of evolution such as selection, mutation and migration as causes or causes. Stephens claims that a causal mechanism account of drift allows us to distinguish it from the other forces, and this distinction is crucial. He further argues that drift has both a direction, i.e., it tends to eliminate heterozygosity. It also has a size which is determined based on population size.
Evolution by Lamarckism
When high school students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). 에볼루션 바카라 사이트 of evolution is often referred to as "Lamarckism" and it states that simple organisms develop into more complex organisms via the inherited characteristics which result from an organism's natural activities usage, use and disuse. Lamarckism is typically illustrated with a picture of a giraffe that extends its neck to reach leaves higher up in the trees. This would cause the necks of giraffes that are longer to be passed to their offspring, who would grow 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 innovative concept that completely challenged the conventional wisdom about organic transformation. According to him living things had evolved from inanimate matter through a series of gradual steps. Lamarck was not the first to suggest this, but he was widely thought of as the first to give the subject a comprehensive and general overview.
The prevailing story is that Lamarckism grew into a rival to Charles Darwin's theory of evolution by natural selection and both theories battled it out in the 19th century. Darwinism eventually triumphed, leading to the development of what biologists now refer to as the Modern Synthesis. This theory denies acquired characteristics can be passed down through generations and instead, it claims that organisms evolve through the selective influence of environmental factors, including Natural Selection.
Lamarck and his contemporaries believed in the idea that acquired characters could be passed down to future generations. However, this concept was never a central part of any of their evolutionary theories. This is due to the fact that it was never tested scientifically.
It has been more than 200 years since the birth of Lamarck, and in the age genomics, there is an increasing evidence base that supports the heritability of acquired traits. It is sometimes referred to as "neo-Lamarckism" or more commonly, epigenetic inheritance. This is a model that is as valid as the popular neodarwinian model.
Evolution through Adaptation
One of the most common misconceptions about evolution is being driven by a struggle to survive. This notion is not true and ignores other forces driving evolution. The fight for survival can be more accurately described as a struggle to survive within a particular environment, which could be a struggle that involves not only other organisms but also the physical environment.
To understand how evolution works it is important to consider what adaptation is. Adaptation is any feature that allows a living thing to live in its environment and reproduce. It could be a physiological structure, such as fur or feathers or a behavioral characteristic such as a tendency to move to the shade during the heat or leaving at night to avoid the cold.
An organism's survival depends on its ability to draw energy from the environment and interact with other organisms and their physical environments. The organism needs to have the right genes to produce offspring, and must be able to locate sufficient food and other resources. Moreover, the organism must be able to reproduce itself in a way that is optimally within its environmental niche.
These factors, together with mutation and gene flow, lead to an alteration in the percentage of alleles (different varieties of a particular gene) in the population's gene pool. Over time, this change in allele frequencies can result in the emergence of new traits and ultimately new species.
Many of the characteristics we admire in animals and plants are adaptations. For example, lungs or gills that draw oxygen from air, fur and feathers as insulation long legs to run away from predators and camouflage to conceal. To comprehend adaptation it is essential to discern between physiological and behavioral traits.
Physiological adaptations, such as thick fur or gills, are physical traits, whereas behavioral adaptations, such as the tendency to seek out companions or to move to shade in hot weather, are not. Furthermore, it is important to note that lack of planning does not mean that something is an adaptation. In fact, failing to consider the consequences of a behavior can make it ineffective despite the fact that it might appear reasonable or even essential.