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 as well as the alteration of the appearance of existing ones.
Numerous examples have been offered of this, such as different varieties of fish called sticklebacks that can be found in salt or fresh water, as well as walking stick insect varieties that are attracted to specific host plants. These typically reversible traits do not explain the fundamental changes in the body's basic plans.
Evolution by Natural Selection
The development of the myriad living creatures on Earth is a mystery that has intrigued scientists for many centuries. The most well-known explanation is Charles Darwin's natural selection process, which occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well-adapted. Over time, a community of well adapted individuals grows and eventually becomes a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity within a species. Inheritance refers to the transmission of genetic traits, which include both dominant and recessive genes to their offspring. Reproduction is the process of producing fertile, viable offspring. This can be achieved via sexual or asexual methods.
All of these variables must be in harmony for natural selection to occur. If, for example, a dominant gene allele makes an organism reproduce and survive more than the recessive gene allele, then the dominant allele becomes more prevalent in a population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will disappear. The process is self-reinforcing, which means that an organism with a beneficial trait can reproduce and survive longer than an individual with a maladaptive characteristic. The higher the level of fitness an organism has which is measured by its ability to reproduce and survive, is the more offspring it produces. People with desirable traits, like a longer neck in giraffes or bright white colors in male peacocks, are more likely to survive and produce offspring, so they will eventually make up the majority of the population over time.
Natural selection is an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or disuse. If a giraffe extends its neck in order to catch prey and its neck gets larger, then its offspring will inherit this trait. The difference in neck length between generations will persist until the giraffe's neck gets too long to not breed with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles at a gene may attain different frequencies in a group through random events. In the end, only one will be fixed (become widespread enough to not longer be eliminated by natural selection) and the rest of the alleles will drop in frequency. In extreme cases, this leads to dominance of a single allele. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small group it could result in the complete elimination the recessive gene. This is known as the bottleneck effect. It is typical of an evolution process that occurs when a large number individuals migrate to form a group.
A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or mass hunting event are concentrated in an area of a limited size. The survivors will share an allele that is dominant and will have the same phenotype. This could be caused by earthquakes, war or even a plague. The genetically distinct population, if it is left, could be susceptible to genetic drift.
Walsh Lewens and Ariew utilize a "purely outcome-oriented" definition of drift as any departure from the expected values for variations in fitness. They cite the famous example of twins that are genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, but the other lives to reproduce.
This type of drift is very important in the evolution of a species. It is not the only method of evolution. Natural selection is the primary alternative, where mutations and migration maintain the phenotypic diversity in the population.
Stephens claims that there is a significant distinction between treating drift as an agent or cause and treating other causes such as selection mutation and migration as causes and forces. He argues that a causal-process explanation of drift lets us differentiate it from other forces and that this distinction is essential. He further argues that drift has a direction: that is it tends to eliminate heterozygosity, and that it also has a magnitude, which is determined by the size of the population.
Evolution through Lamarckism
When students in high school study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is generally referred to as "Lamarckism" and it states that simple organisms develop into more complex organisms via the inheritance of characteristics that result from the organism's natural actions usage, use and disuse. Lamarckism is typically illustrated by a picture of a giraffe that extends its neck longer to reach the higher branches in the trees. This could cause giraffes to pass on their longer necks to their offspring, who then get taller.
Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate Zoology at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced an original idea that fundamentally challenged the conventional wisdom 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 but he was considered to be the first to give the subject a thorough and general explanation.
The most popular story is that Lamarckism was a rival to Charles Darwin's theory of evolution through natural selection and that the two theories fought each other in the 19th century. Darwinism eventually prevailed, leading to the development of what biologists now 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, including Natural Selection.
Although Lamarck endorsed the idea of inheritance through acquired characters and his contemporaries also offered a few words about this idea, it was never a central element in any of their evolutionary theories. This is partly 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 amount of evidence that supports the heritability of acquired characteristics. This is referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a version that is as reliable as the popular neodarwinian model.
Evolution by adaptation
One of the most common misconceptions about evolution is its being driven by a struggle for survival. This is a false assumption and overlooks other forces that drive evolution. 에볼루션카지노 for survival is better described as a fight to survive in a specific environment. This could include not just other organisms, but also the physical environment itself.
Understanding how adaptation works is essential to understand evolution. The term "adaptation" refers to any specific characteristic that allows an organism to live and reproduce within its environment. It could be a physiological feature, like feathers or fur, or a behavioral trait, such as moving to the shade during hot weather or coming out at night to avoid the cold.
The survival of an organism is dependent on its ability to draw energy from the surrounding environment and interact with other organisms and their physical environments. The organism needs to have the right genes to produce offspring, and it must be able to locate enough food and other resources. The organism should also be able to reproduce itself at an amount that is appropriate for its specific niche.
These factors, along with mutation and gene flow can result in changes in the ratio of alleles (different types of a gene) in the gene pool of a population. Over time, this change in allele frequency can lead to the emergence of new traits and eventually new species.
Many of the features that we admire in animals and plants are adaptations, for example, the lungs or gills that extract oxygen from the air, feathers or fur to protect themselves long legs to run away from predators and camouflage to hide. However, a proper understanding of adaptation requires paying attention to the distinction between the physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills, are physical traits, while behavioral adaptations, such as the desire to find companions or to move to shade in hot weather, aren't. It is important to remember that a lack of planning does not make an adaptation. Failure to consider the effects of a behavior even if it seems to be logical, can make it unadaptive.
