• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

What is Free Evolution?

Free evolution is the concept that natural processes can cause organisms to evolve over time. This includes the emergence and development of new species.

This is evident in numerous examples of stickleback fish species that can live in salt or fresh water, and walking stick insect types that are apprehensive about particular host plants. These reversible traits however, are not able to explain fundamental changes in basic body plans.

Evolution through Natural Selection

The evolution of the myriad living organisms on Earth is a mystery that has intrigued scientists for decades. Charles Darwin's natural selection is the most well-known explanation. This is because individuals who are better-adapted have more success in reproduction and survival 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 that are: reproduction, variation and inheritance. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity within a species. Inheritance is the term used to describe the transmission of a person's genetic traits, which include recessive and dominant genes and their offspring. Reproduction is the production of fertile, viable offspring which includes both sexual and asexual methods.

All of these factors have to be in equilibrium to allow natural selection to take place. For example, if a dominant allele at a gene can cause an organism to live and reproduce more often than the recessive allele the dominant allele will be more common within the population. But if the allele confers a disadvantage in survival or decreases fertility, it will disappear from the population. The process is self-reinforcing, meaning that an organism that has a beneficial trait will survive and reproduce more 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 characteristics, like a longer neck in giraffes and bright white color patterns in male peacocks are more likely survive and produce offspring, so they will make up the majority of the population over time.

Natural selection only affects populations, not individual organisms. This is an important distinction from the Lamarckian theory of evolution which argues that animals acquire characteristics by use or inactivity. For instance, if the giraffe's neck gets longer through stretching to reach for prey and its offspring will inherit a more long neck. The difference in neck size between generations will continue to grow until the giraffe becomes unable to breed with other giraffes.

Evolution by Genetic Drift

Genetic drift occurs when the alleles of the same gene are randomly distributed within a population. In the end, one will attain fixation (become so common that it is unable to be eliminated by natural selection) and the other alleles drop to lower frequencies. This can lead to dominance at the extreme. The other alleles are basically eliminated and heterozygosity has diminished to a minimum. In a small group, this could lead to the complete elimination of recessive allele. This is known as a bottleneck effect and it is typical of evolutionary process when a large amount of people migrate to form a new population.

A phenotypic bottleneck may happen when the survivors of a catastrophe like an epidemic or a mass hunting event, are concentrated within a narrow area. The survivors will have a dominant allele and thus will have the same phenotype. This may be caused by a war, earthquake or even a disease. Regardless of the cause the genetically distinct population that remains could be prone to genetic drift.

Walsh Lewens, Lewens, and Ariew use Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They give the famous example of twins that are genetically identical and share the same phenotype. However one is struck by lightning and dies, whereas the other is able to reproduce.

This kind of drift can be very important in the evolution of the species. However, 바카라 에볼루션 it is not the only way to develop. Natural selection is the primary alternative, in which mutations and migration maintain phenotypic diversity within the population.

Stephens argues that there is a major distinction between treating drift as a force or a cause and considering other causes of evolution such as selection, mutation and migration as forces or causes. He claims that a causal-process explanation of drift lets us distinguish it from other forces and this distinction is essential. He also argues that drift has a direction: that is, it tends to eliminate heterozygosity. It also has a magnitude, that is determined by the size of population.

Evolution by Lamarckism

In high school, students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is generally called "Lamarckism" and 바카라 에볼루션 코리아, look these up, it states that simple organisms grow into more complex organisms by the inheritance of traits which result from the organism's natural actions usage, use and disuse. Lamarckism is typically illustrated by a picture of a giraffe stretching its neck longer to reach higher up in the trees. This causes giraffes' longer necks to be passed to their offspring, who would grow taller.

Lamarck was a French zoologist and, in his opening lecture for his course on invertebrate zoology at the Museum of Natural History in Paris on 17 May 1802, he introduced an innovative concept that completely challenged previous thinking about organic transformation. According to him living things had evolved from inanimate matter via a series of gradual steps. Lamarck wasn't the only one to make this claim however he was widely thought of as the first to offer the subject a comprehensive and general overview.

The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were competing in the 19th century. Darwinism eventually prevailed and led to the creation of what biologists today call the Modern Synthesis. The theory denies that acquired characteristics can be passed down and instead argues organisms evolve by the influence of environment factors, including Natural Selection.

Lamarck and his contemporaries believed in the notion that acquired characters could be passed on to the next generation. However, this notion was never a major 에볼루션 part of any of their theories on evolution. This is due to the fact that it was never tested scientifically.

It's been more than 200 years since Lamarck was born and, in the age of genomics there is a vast body of evidence supporting the heritability of acquired characteristics. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. It is a variant of evolution that is as valid as the more well-known Neo-Darwinian model.

Evolution through the process of adaptation

One of the most common misconceptions about evolution is that it is driven by a sort of struggle to survive. In fact, this view misrepresents natural selection and ignores the other forces that are driving evolution. The struggle for survival is more accurately described as a struggle to survive within a particular environment, which can include not just other organisms but as well the physical environment.

To understand how evolution operates it is beneficial to understand what is adaptation. The term "adaptation" refers to any characteristic that allows a living organism to live in its environment and reproduce. It could be a physiological structure, such as feathers or fur, or a behavioral trait like moving into shade in 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 living organisms and their physical surroundings. The organism must possess the right genes to generate offspring, and it should be able to locate sufficient food and other resources. The organism must be able to reproduce at a rate that is optimal for its specific niche.

These factors, along with mutation and gene flow can result in a change in the proportion of alleles (different types of a gene) in the population's gene pool. As time passes, this shift in allele frequencies can lead to the emergence of new traits, and eventually new species.

A lot of the traits we find appealing in animals and plants are adaptations. For instance lung or gills that extract oxygen from the air, fur and feathers as insulation, long legs to run away from predators, and camouflage to hide. However, a complete understanding of adaptation requires a keen eye to the distinction between physiological and behavioral traits.

Physiological adaptations like thick fur or gills, are physical traits, whereas behavioral adaptations, like the tendency to seek out friends or to move into the shade in hot weather, aren't. In addition it is important to understand that lack of planning does not mean that something is an adaptation. In fact, failing to consider the consequences of a decision can render it ineffective even though it appears to be logical or 에볼루션 무료체험 even necessary.