What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can cause them to develop over time. This includes the creation of new species and alteration of the appearance of existing species.
This is evident in many examples of stickleback fish species that can be found in salt or fresh water, and walking stick insect types that have a preference for specific host plants. These reversible traits are not able to explain fundamental changes to basic body plans.
Evolution through Natural Selection
The evolution of the myriad living organisms on Earth is an enigma that has fascinated scientists for many centuries. Charles Darwin's natural selectivity is the best-established explanation. This process occurs when people who are more well-adapted have more success in reproduction and survival than those who are less well-adapted. Over time, the population of well-adapted individuals grows and eventually creates an entirely new species.
Natural selection is an ongoing process that involves the interaction of three elements including inheritance, variation, and reproduction. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity of a species. Inheritance refers to the transmission of a person’s genetic traits, including recessive and dominant genes to their offspring. Reproduction is the process of producing fertile, viable offspring which includes both sexual and asexual methods.
Natural selection can only occur when all these elements are in harmony. For instance the case where an allele that is dominant at a gene can cause an organism to live and reproduce more frequently than the recessive one, the dominant allele will be more prominent in the population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will go away. This process is self-reinforcing meaning that an organism with a beneficial trait will survive and reproduce more than one with an unadaptive trait. The more offspring an organism produces the more fit it is, which is measured by its capacity to reproduce itself and live. Individuals with favorable characteristics, such as a long neck in giraffes, or bright white color patterns on male peacocks are more likely to others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection is only an element in the population and not on individuals. This is a crucial distinction from the Lamarckian evolution theory, which states that animals acquire traits through usage or inaction. If a giraffe expands its neck to catch prey and the neck grows larger, then its offspring will inherit this characteristic. The difference in neck length between generations will continue until the giraffe's neck gets too long that it can not breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of one gene are distributed randomly within a population. In the end, one will attain fixation (become so widespread that it cannot be eliminated through natural selection) and other alleles will fall to lower frequencies. This could lead to a dominant allele at the extreme. The other alleles are essentially eliminated and heterozygosity has diminished to a minimum. In a small group this could result in the total elimination of the recessive allele. 에볼루션 무료체험 is called a bottleneck effect, and it is typical of evolutionary process that takes place when a large amount of people migrate to form a new population.
A phenotypic bottleneck can also occur when survivors of a disaster like an outbreak or a mass hunting event are confined to the same area. The surviving individuals are likely to be homozygous for the dominant allele which means that they will all have the same phenotype and therefore share the same fitness characteristics. This can be caused by earthquakes, war or even a plague. Regardless of the cause the genetically distinct population that remains is prone to genetic drift.
Walsh, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any departure from expected values for differences in fitness. They provide a well-known example of twins that are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could play a crucial part in the evolution of an organism. This isn't the only method of evolution. Natural selection is the primary alternative, in which mutations and migrations maintain the phenotypic diversity in the population.
Stephens asserts that there is a huge distinction between treating drift as an agent or cause and treating other causes like migration and selection as causes and forces. Stephens claims that a causal mechanism account of drift permits us to differentiate it from other forces, and that this distinction is essential. He argues further that drift has a direction, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined by population size.
Evolution by 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, often referred to as “Lamarckism” is based on the idea that simple organisms evolve into more complex organisms through inheriting characteristics that result from the use and abuse of an organism. Lamarckism is illustrated through a giraffe extending its neck to reach higher leaves in the trees. This process would cause giraffes to give their longer necks to their offspring, who would then grow even taller.
Lamarck the French Zoologist from France, presented an idea that was revolutionary in his opening lecture at the Museum of Natural History of Paris. He challenged the conventional wisdom on organic transformation. According to Lamarck, living things evolved from inanimate material through a series of gradual steps. Lamarck wasn't the only one to make this claim but he was thought of as the first to give the subject a comprehensive and general explanation.
The most popular story is that Charles Darwin's theory on natural selection and Lamarckism were competing in the 19th Century. Darwinism ultimately won which led to what biologists refer to as the Modern Synthesis. This theory denies acquired characteristics are passed down from generation to generation and instead argues organisms evolve by the influence of environment factors, including Natural Selection.
While Lamarck supported the notion of inheritance by acquired characters and his contemporaries paid lip-service to this notion, it was never a major feature in any of their evolutionary theories. This is partly because it was never scientifically validated.
However, it has been more than 200 years since Lamarck was born and in the age genomics there is a huge body of evidence supporting the heritability of acquired characteristics. This is also known 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 adaptation
One of the most common misconceptions about evolution is that it is driven by a type of struggle for survival. In reality, this notion is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The fight for survival can be more effectively 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 itself.
Understanding how original site is essential to understand evolution. The term "adaptation" refers to any characteristic that allows living organisms to live in its environment and reproduce. It can be a physical feature, like fur or feathers. It could also be a trait of behavior such as moving to the shade during the heat, or escaping the cold at night.
The capacity of a living thing to extract energy from its surroundings and interact with other organisms and their physical environments, is crucial to its survival. The organism must have the right genes for producing offspring and be able find enough food and resources. 에볼루션 무료체험 must be able to reproduce at the rate that is suitable for its niche.
These factors, along with gene flow and mutation can result in an alteration in the percentage of alleles (different varieties of a particular gene) in the gene pool of a population. This shift in the frequency of alleles can lead to the emergence of new traits and eventually, new species as time passes.
Many of the characteristics we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, feathers or fur to protect themselves long legs to run away from predators and camouflage to hide. However, a thorough understanding of adaptation requires paying attention to the distinction between behavioral and physiological traits.
Physiological adaptations like thick fur or gills, are physical traits, while behavioral adaptations, like the tendency to search for friends or to move to the shade during hot weather, are not. It is important to remember that a insufficient planning does not cause an adaptation. Failure to consider the implications of a choice, even if it appears to be logical, can make it unadaptive.