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 creation of new species as well as the alteration of the appearance of existing species.
Numerous examples have been offered of this, such as different varieties of stickleback fish that can be found in salt or fresh water, and walking stick insect varieties that favor particular host plants. These are mostly reversible traits, however, cannot explain fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is a mystery that has intrigued scientists for centuries. The most widely accepted explanation is Darwin's natural selection process, an evolutionary process that occurs when individuals that are better adapted survive and reproduce more successfully than those less well adapted. Over time, the population of well-adapted individuals grows and eventually develops into a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors including reproduction, variation and inheritance. Mutation and sexual reproduction increase genetic diversity in an animal species. Inheritance is the passing of a person's genetic traits to their offspring that includes recessive and dominant alleles. Reproduction is the process of generating viable, fertile offspring. This can be done through sexual or asexual methods.
Natural selection can only occur when all these elements are in balance. For instance the case where the dominant allele of a gene can cause an organism to live and reproduce more often than the recessive one, the dominant allele will be more common within the population. However, if the gene confers a disadvantage in survival or reduces fertility, it will disappear from the population. The process is self-reinforcing which means that an organism that has an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive trait. The more offspring that an organism has, the greater its fitness, which is measured by its ability to reproduce and survive. People with desirable traits, such as having a longer neck in giraffes and bright white color patterns in male peacocks are more likely to survive and have offspring, so they will make up the majority of the population over time.
Natural selection is only an aspect of populations and not on 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 larger, then its children will inherit this characteristic. The length difference between generations will continue until the neck of the giraffe becomes so long that it can not breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of a gene are randomly distributed in a group. At some point, one will attain fixation (become so widespread that it is unable to be eliminated by natural selection), while other alleles will fall to lower frequencies. In the extreme this, it leads to a single allele dominance. The other alleles are essentially eliminated, and heterozygosity falls to zero. In a small number of people, this could result in the complete elimination of the recessive gene. This scenario is called the bottleneck effect and is typical of the evolution process that occurs when a large number individuals migrate to form a population.
A phenotypic bottleneck may occur when the survivors of a catastrophe like an epidemic or a mass hunt, are confined within a narrow area. The survivors will share an dominant allele, and will have the same phenotype. This situation could be caused by war, earthquakes, or even plagues. The genetically distinct population, if it is left vulnerable to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from expected values due to differences in fitness. They give the famous example of twins who are genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, while the other lives to reproduce.
This type of drift is vital to the evolution of an entire species. However, it is not the only method to progress. The primary alternative is to use a process known as natural selection, where the phenotypic diversity of a population is maintained by mutation and migration.
Stephens claims that there is a big difference between treating the phenomenon of drift as a force or as a cause and considering other causes of evolution, such as selection, mutation and migration as causes or causes. He claims 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 a direction, that is, it tends to eliminate heterozygosity, and that it also has a size, that 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, also referred to as "Lamarckism is based on the idea that simple organisms evolve into more complex organisms through inheriting characteristics that result from the organism's use and misuse. Lamarckism is illustrated through a giraffe extending its neck to reach higher branches in the trees. This would cause the longer necks of giraffes to be passed to their offspring, who would grow taller.
Lamarck Lamarck, a French Zoologist, introduced a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. In his opinion living things had evolved from inanimate matter through a series of gradual steps. Lamarck wasn't the only one to suggest this however he was widely considered to be the first to offer the subject a thorough and general treatment.
The most popular story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were rivals in the 19th century. Darwinism eventually prevailed and led to the development of what biologists now refer to as the Modern Synthesis. The theory argues that acquired traits can be passed down and instead argues organisms evolve by the influence of environment elements, like Natural Selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed down to future generations. However, this notion was never a central part of any of their evolutionary theories. This is largely due to the fact that it was never validated scientifically.
However, it has been more than 200 years since Lamarck was born and in the age of genomics there is a huge amount of evidence to support the possibility of inheritance of acquired traits. This is referred to as "neo Lamarckism", or more often epigenetic inheritance. It is a form of evolution that is as valid as the more popular Neo-Darwinian theory.
Evolution by the process of adaptation
One of the most popular misconceptions about evolution is that it is driven by a type of struggle for survival. 에볼루션 게이밍 is inaccurate and overlooks other forces that drive evolution. The struggle for survival is more effectively described as a struggle to survive within a specific environment, which can be a struggle that involves not only other organisms but also the physical environment.
Understanding the concept of adaptation is crucial to understand evolution. Adaptation refers to any particular feature that allows an organism to survive and reproduce within its environment. It can be a physiological feature, like feathers or fur or a behavior like moving to the shade during hot weather or coming out at night to avoid the cold.
The survival of an organism depends on its ability to draw energy from the surrounding environment and interact with other organisms and their physical environments. The organism must possess the right genes to produce offspring and be able find enough food and resources. The organism must be able to reproduce itself at the rate that is suitable for its specific niche.
These factors, together with mutation and gene flow, lead to a change in the proportion of alleles (different types of a gene) in a population's gene pool. The change in frequency of alleles could lead to the development of novel traits and eventually new species in the course of time.
A lot of the traits we admire in animals and plants are adaptations. For instance lung or gills that draw oxygen from air feathers and fur for insulation long legs to run away from predators, and camouflage to hide. To understand the concept of adaptation it is crucial to discern between physiological and behavioral traits.
Physiological adaptations, like thick fur or gills are physical traits, whereas behavioral adaptations, like the desire to find companions or to retreat into the shade in hot weather, aren't. It is important to note that lack of planning does not cause an adaptation. A failure to consider the consequences of a decision, even if it appears to be logical, can make it unadaptive.