What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can lead them to evolve over time. This includes the evolution of new species and the alteration of the appearance of existing species.
This has been demonstrated by many examples of stickleback fish species that can live in fresh or saltwater and walking stick insect types that are apprehensive about particular host plants. These reversible traits do not explain the fundamental changes in the basic body plan.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all living creatures that live on our planet for centuries. Charles Darwin's natural selection 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, a community of well-adapted individuals increases and eventually becomes a new species.
Natural selection is a cyclical process that involves the interaction of three factors: variation, inheritance and reproduction. Variation is caused by mutation and sexual reproduction, both of which increase the genetic diversity of a species. Inheritance is the term used to describe the transmission of genetic traits, which include both dominant and recessive genes to their offspring. Reproduction is the process of generating viable, fertile offspring. This can be accomplished through sexual or asexual methods.
All of these elements must be in harmony for natural selection to occur. If, for example, a dominant gene allele allows an organism to reproduce and survive more than the recessive gene The dominant allele will become more prevalent in a population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will be eliminated. The process is self-reinforcing which means that the organism with an adaptive trait will survive and reproduce more quickly than those with a maladaptive feature. The more offspring an organism produces the better its fitness which is measured by its capacity to reproduce and survive. mouse click the following article with good traits, such as longer necks in giraffes or bright white color patterns in male peacocks are more likely to survive and have offspring, which means they will become the majority of the population over time.
Natural selection is only an element in the population and not on individuals. This is a significant distinction from the Lamarckian evolution theory which holds that animals acquire traits due to the use or absence of use. For example, if a animal's neck is lengthened by stretching to reach prey and its offspring will inherit a larger neck. The difference in neck size between generations will continue to grow until the giraffe is unable to reproduce with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a population. At some point, one will reach fixation (become so widespread that it is unable to be eliminated through natural selection) and other alleles fall to lower frequency. In extreme cases, this leads to dominance of a single allele. The other alleles are virtually eliminated and heterozygosity decreased to a minimum. In a small group it could lead to the total elimination of recessive alleles. This is known as the bottleneck effect. It is typical of the evolution process that occurs when the number of individuals migrate to form a population.
A phenotypic 'bottleneck' can also occur when survivors of a disaster like an outbreak or a mass hunting event are concentrated in an area of a limited size. The survivors will have an allele that is dominant and will share the same phenotype. This situation might be the result of a war, an earthquake or even a cholera outbreak. Regardless of the cause, the genetically distinct population that remains could be susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a deviation from the expected value due to differences in fitness. They cite the famous example of twins who are genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, but the other is able to reproduce.
This kind of drift can play a crucial role in the evolution of an organism. But, it's not the only method to progress. The main alternative is a process called natural selection, in which phenotypic variation in an individual is maintained through mutation and migration.
Stephens argues there is a vast difference between treating the phenomenon of drift as a force or cause, and treating other causes such as migration and selection as forces and causes. He claims that a causal-process account of drift allows us distinguish it from other forces and that this distinction is essential. He also argues that drift has both direction, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by population size.
Evolution through Lamarckism
In high school, students 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 by taking on traits that are a product of the use and abuse of an organism. Lamarckism is typically illustrated with a picture of a giraffe stretching its neck longer to reach higher up in the trees. This process would cause giraffes to pass on their longer necks to their offspring, who then grow even taller.
Lamarck, a French Zoologist, introduced an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. According to him living things evolved from inanimate matter through the gradual progression of events. Lamarck was not the only one to suggest that this might be the case, but the general consensus is that he was the one having given the subject his first comprehensive and comprehensive 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 won and led to the development of what biologists today 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, like natural selection.
Although Lamarck supported the notion of inheritance through acquired characters and his contemporaries spoke of this idea however, it was not a major feature in any of their evolutionary theories. This is due in part to the fact that it was never validated scientifically.
But it is now more than 200 years since Lamarck was born and in the age of genomics there is a vast amount of evidence that supports the heritability of acquired traits. It is sometimes referred to as "neo-Lamarckism" or more commonly, epigenetic inheritance. This is a version that is just as valid as the popular neodarwinian model.
Evolution by the process of adaptation
One of the most widespread misconceptions about evolution is that it is driven by a type of struggle to survive. This view is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The fight for survival can be more precisely described as a fight to survive within a particular environment, which can include not just other organisms, but as well the physical environment.
Understanding the concept of adaptation is crucial to understand evolution. The term "adaptation" refers to any specific feature that allows an organism to live and reproduce in its environment. It can be a physical feature, like fur or feathers. Or it can be a behavior trait such as moving to the shade during hot weather, or coming out to avoid the cold at night.
The ability of an organism to draw energy from its environment and interact with other organisms and their physical environment is essential to its survival. The organism must possess the right genes to create offspring, and must be able to locate sufficient food and other resources. In addition, the organism should be capable of reproducing in a way that is optimally within its environment.
These factors, together with mutations and gene flow can cause an alteration in the ratio of different alleles in the population's gene pool. The change in frequency of alleles can lead to the emergence of novel traits and eventually new species in the course of time.
A lot of the traits we admire about animals and plants are adaptations, like lung or gills for removing oxygen from the air, fur or feathers for insulation, long legs for running away from predators, and camouflage to hide. To understand the concept of adaptation it is crucial to distinguish between behavioral and physiological traits.
Physiological adaptations, such as thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to seek out companions or to move to the shade during hot weather, are not. Additionally it is important to remember that a lack of forethought does not make something an adaptation. In fact, failing to think about the consequences of a behavior can make it ineffective, despite the fact that it appears to be sensible or even necessary.