What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can lead to their development over time. This includes the development of new species and transformation of the appearance of existing ones.
This has been proven by many examples of stickleback fish species that can live in saltwater or fresh water and walking stick insect species that prefer particular host plants. These reversible traits cannot explain fundamental changes to the basic body plan.
Evolution by Natural Selection
The evolution of the myriad living organisms on Earth is a mystery that has intrigued scientists for decades. The most widely accepted explanation is Darwin's natural selection process, an evolutionary process that is triggered when more well-adapted individuals live longer and reproduce more effectively than those that are less well adapted. Over time, a population of well adapted individuals grows and eventually forms a whole new species.
Natural selection is an ongoing process that is characterized by the interaction of three elements: variation, inheritance and reproduction. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity of an animal species. Inheritance refers to the passing of a person's genetic traits to their offspring which includes both recessive and dominant alleles. Reproduction is the process of producing fertile, viable offspring. This can be achieved by both asexual or sexual methods.
Natural selection only occurs when all these elements are in equilibrium. If, for example an allele of a dominant gene allows an organism to reproduce and survive more than the recessive gene then the dominant allele becomes more prevalent in a population. If 무료 에볼루션 confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. The process is self-reinforcing which means that an organism with an adaptive trait will survive and reproduce more quickly than one with a maladaptive characteristic. The more offspring that an organism has, the greater its fitness that is determined by its capacity to reproduce itself and survive. People with desirable traits, like the long neck of giraffes, or bright white color patterns on male peacocks, are more likely than others to reproduce and survive which eventually leads to them becoming the majority.
Natural selection is only a force for populations, not on individuals. This is a major distinction from the Lamarckian theory of evolution that states that animals acquire traits due to use or lack of use. If a giraffe extends its neck to reach prey and the neck grows larger, then its children will inherit this characteristic. The difference in neck length between generations will continue until the giraffe's neck becomes too long to not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when the alleles of one gene are distributed randomly within a population. In the end, one will reach fixation (become so common that it is unable to be removed by natural selection), while other alleles will fall to lower frequencies. In the extreme it can lead to dominance of a single allele. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small number of people this could result in the complete elimination of the recessive allele. This is called a bottleneck effect, and it is typical of evolutionary process that takes place when a large number of individuals move to form a new group.
A phenotypic bottleneck may occur when survivors of a disaster like an epidemic or mass hunting event, are concentrated in a limited area. The survivors will be largely homozygous for the dominant allele, which means they will all share the same phenotype and therefore have the same fitness traits. This situation might be caused by conflict, earthquake or even a cholera outbreak. Whatever the reason the genetically distinct group that remains could be prone to genetic drift.
Walsh Lewens and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for variations in fitness. They provide a well-known instance of twins who are genetically identical and have identical phenotypes but one is struck by lightening and dies while the other lives and reproduces.
This type of drift can play a significant role in the evolution of an organism. However, it's not the only method to develop. The most common alternative is a process called natural selection, where phenotypic variation in an individual is maintained through mutation and migration.
Stephens argues that there is a major difference between treating drift as a force, or a cause and considering other causes of evolution like selection, mutation, and migration as forces or causes. He argues that a causal process account of drift allows us to distinguish it from other forces, and this distinction is crucial. He also argues that drift has direction, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined by 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 referred to as “Lamarckism”, states that simple organisms transform into more complex organisms through adopting traits that are a product of the use and abuse of an organism. Lamarckism is illustrated through the giraffe's neck being extended to reach higher leaves in the trees. This could cause giraffes' longer necks to be passed onto their 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 a groundbreaking concept that radically challenged previous thinking about organic transformation. In his opinion living things evolved from inanimate matter through a series of gradual steps. Lamarck was not the first to propose this, but he was widely thought of as the first to give the subject a comprehensive and general treatment.
The most popular story is that Charles Darwin's theory of natural selection and Lamarckism were rivals in the 19th century. Darwinism eventually won and led to the creation of what biologists refer to as the Modern Synthesis. The theory argues that acquired characteristics can be inherited and instead argues that organisms evolve by the symbiosis of environmental factors, including natural selection.
While Lamarck supported the notion of inheritance through acquired characters, and his contemporaries also spoke of this idea, it was never an integral part of any of their evolutionary theorizing. This is largely due to the fact that it was never tested scientifically.
But it is now more than 200 years since Lamarck was born and in the age genomics there is a vast body of evidence supporting the heritability of acquired traits. This is also known as "neo Lamarckism", or more often epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model.
Evolution by the process of 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 ignores other forces driving evolution. The fight for survival can be more effectively described as a struggle to survive in a specific environment, which could involve not only other organisms, but as well the physical environment.
To understand how evolution operates, it is helpful to understand what is adaptation. It is a feature that allows a living organism to live in its environment and reproduce. It can be a physiological structure like feathers or fur or a behavior like moving into the shade in hot weather or stepping out at night to avoid the cold.
The capacity of a living thing to extract energy from its environment and interact with other organisms, as well as their physical environments, is crucial to its survival. 무료에볼루션 must possess the right genes to create offspring, and be able to find sufficient food and resources. In 무료 에볼루션 , the organism should be able to reproduce itself 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 novel traits and eventually, new species as time passes.
A lot of the traits we find appealing in plants and animals are adaptations. For instance lung or gills that draw oxygen from air feathers and fur as insulation, long legs to run away from predators and camouflage to conceal. To understand adaptation it is crucial to differentiate between physiological and behavioral traits.
Physical traits such as large gills and thick fur are physical characteristics. Behavior adaptations aren't like the tendency of animals to seek companionship or to retreat into the shade in hot weather. Additionally it is important to understand that a lack of forethought is not a reason to make something an adaptation. In fact, failure to think about the implications of a choice can render it ineffective, despite the fact that it may appear to be sensible or even necessary.