What is Free Evolution?
Free evolution is the concept that natural processes can lead to the development of organisms over time. This includes the emergence and development of new species.
This is evident in many examples such as the stickleback fish species that can thrive in fresh or saltwater and walking stick insect species that have a preference for particular host plants. These are mostly reversible traits, however, cannot be the reason for fundamental changes in body plans.
Evolution through Natural Selection
The development of the myriad of living creatures on Earth is a mystery that has intrigued scientists for decades. The most well-known explanation is Darwin's natural selection, which 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 becomes larger and eventually forms an entirely new species.
visit is an ongoing process and involves the interaction of three factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity of a species. Inheritance refers the transmission of a person’s genetic traits, including recessive and dominant genes, to their offspring. visit is the process of producing viable, fertile offspring. This can be achieved by both asexual or sexual methods.
Natural selection can only occur when all the factors are in equilibrium. If, for example an allele of a dominant gene makes an organism reproduce and survive more than the recessive gene allele The dominant allele becomes more prevalent in a population. But if the allele confers an unfavorable survival advantage or decreases fertility, it will disappear from the population. The process is self-reinforcing meaning that the organism with an adaptive trait will live and reproduce much more than one with a maladaptive characteristic. The greater an organism's fitness as measured by its capacity to reproduce and survive, is the greater number of offspring it can produce. People with desirable traits, such as longer necks in giraffes and bright white patterns of color in male peacocks, are more likely to survive and produce offspring, and thus will make up the majority of the population over time.
Natural selection is only a factor in populations and not on individuals. This is an important distinction from the Lamarckian theory of evolution, which claims that animals acquire characteristics through use or disuse. For example, if a animal's neck is lengthened by stretching to reach prey, its offspring will inherit a longer neck. The differences in neck size between generations will continue to increase until the giraffe is unable to reproduce with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of one gene are distributed randomly within a population. At some point, only one of them will be fixed (become common enough to no longer be eliminated through natural selection) and the other alleles will drop in frequency. This could lead to dominance in the extreme. Other alleles have been basically eliminated and heterozygosity has diminished to zero. In a small group this could lead to the complete elimination of the recessive gene. This is known as a bottleneck effect and it is typical of evolutionary process that takes place when a lot of individuals move to form a new group.
A phenotypic bottleneck could occur when survivors of a catastrophe like an epidemic or a mass hunting event, are concentrated in a limited area. The surviving individuals will be mostly homozygous for the dominant allele, which means they will all have the same phenotype and will thus have the same fitness traits. This situation could be caused by war, earthquakes, or even plagues. Regardless of the cause the genetically distinct population that remains is susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a deviation from expected values due to differences in fitness. They provide a well-known instance of twins who are genetically identical, have identical phenotypes, and yet one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift could play a very important role in the evolution of an organism. But, it's not the only method to progress. The main alternative is to use a process known as natural selection, in which the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens claims that there is a vast difference between treating drift like a force or cause, and treating other causes such as migration and selection as causes and forces. He argues that a causal-process explanation of drift lets us distinguish it from other forces and that this distinction is essential. He further argues that drift is both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size, that is determined by population size.
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, commonly referred to as “Lamarckism” is based on the idea that simple organisms transform into more complex organisms taking on traits that result from an organism's use and disuse. Lamarckism is usually illustrated with a picture of a giraffe stretching its neck to reach higher up in the trees. This could cause giraffes' longer necks to be passed onto their offspring who would then become taller.
에볼루션바카라사이트 was a French zoologist and, 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 introduced an original idea that fundamentally challenged the previous understanding of organic transformation. According Lamarck, living organisms evolved from inanimate materials through a series of gradual steps. Lamarck was not the only one to suggest that this might be the case but he is widely seen as having given the subject its first general and comprehensive analysis.
The popular narrative is that Lamarckism grew into a rival to Charles Darwin's theory of evolutionary natural selection and both theories battled out in the 19th century. Darwinism ultimately prevailed and led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics can be passed down through generations and instead, it claims that organisms evolve through the selective influence of environmental elements, like 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 key element of any of their theories about evolution. This is partly because it was never scientifically validated.
But it is now more than 200 years since Lamarck was born and in the age of genomics there is a huge body of evidence supporting the heritability of acquired traits. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. It is a version of evolution that is as valid as the more popular Neo-Darwinian theory.
Evolution by Adaptation
One of the most commonly-held misconceptions about evolution is being driven by a struggle for survival. This is a false assumption and overlooks other forces that drive evolution. The fight for survival can be more accurately 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.
To understand how evolution works, it is helpful to understand what is adaptation. The term "adaptation" refers to any specific characteristic that allows an organism to live and reproduce in its environment. It can be a physical structure, like fur or feathers. It could also be a trait of behavior such as moving to the shade during hot weather, or escaping the cold at night.
The ability of an organism to extract energy from its surroundings and interact with other organisms and their physical environment is essential to its survival. The organism must have the right genes to produce offspring and be able find enough food and resources. The organism should also be able to reproduce itself at a rate that is optimal for its particular niche.
These factors, in conjunction with gene flow and mutations can result in changes in the proportion of different alleles within a population’s gene pool. Over time, this change in allele frequencies could result in the emergence of new traits and eventually new species.
A lot of the traits we admire about animals and plants are adaptations, like the lungs or gills that extract oxygen from the air, feathers or fur for insulation, long legs for running away from predators and camouflage for hiding. To understand the concept of adaptation, it is important to distinguish between behavioral and physiological characteristics.
Physiological adaptations like thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the desire to find friends or to move into the shade in hot weather, aren't. In addition it is important to understand that a lack of forethought does not mean that something is an adaptation. Failure to consider the effects of a behavior, even if it appears to be logical, can make it inflexible.