What is Free Evolution?
Free evolution is the concept that the natural processes of living organisms can lead to their development over time. This includes the appearance and development of new species.
Many examples have been given of this, such as different varieties of fish called sticklebacks that can be found in salt or fresh water, and walking stick insect varieties that prefer particular host plants. These mostly reversible traits permutations cannot explain fundamental changes to basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the evolution of all living creatures that live on our planet for centuries. The most well-known explanation is Darwin's natural selection, an evolutionary process that is triggered when more well-adapted individuals live longer and reproduce more effectively than those who are less well-adapted. As time passes, the number of individuals who are well-adapted grows and eventually develops into a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors: variation, reproduction and inheritance. Sexual reproduction and mutations increase genetic diversity in an animal species. Inheritance refers the transmission of a person's genetic characteristics, which includes recessive and dominant genes to their offspring. Reproduction is the process of producing fertile, viable offspring. This can be achieved by both asexual or sexual methods.
All of these factors must be in balance for natural selection to occur. If, for instance the dominant gene allele causes an organism reproduce and live longer than the recessive gene allele, then the dominant allele becomes more prevalent in a group. If the allele confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. The process is self-reinforcing, which means that an organism that has an adaptive trait will live and reproduce far more effectively than those with a maladaptive trait. 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 characteristics, such as having a long neck in the giraffe, or bright white color patterns on male peacocks are more likely than others to survive and reproduce, which will eventually lead to them becoming the majority.
Natural selection only acts on populations, not on individuals. This is an important distinction from the Lamarckian theory of evolution, which argues that animals acquire characteristics by use or inactivity. For example, if a animal's neck is lengthened by reaching out to catch prey its offspring will inherit a longer neck. The difference in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles at a gene may be at different frequencies in a group by chance events. At some point, one will attain fixation (become so widespread that it is unable to be eliminated through natural selection), while other alleles will fall to lower frequencies. This could lead to a dominant allele at the extreme. The other alleles are eliminated, and heterozygosity falls to zero. In a small number of people this could result in the complete elimination of the recessive allele. This is called a bottleneck effect, and it is typical of evolutionary process when a large number of individuals move to form a new group.
A phenotypic bottleneck can also happen when the survivors of a catastrophe, such as an epidemic or mass hunting event, are concentrated into a small area. The survivors will share a dominant allele and thus will share the same phenotype. This situation could be caused by earthquakes, war, or even plagues. The genetically distinct population, if it is left susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected values due to differences in fitness. They give a famous example of twins that are genetically identical, have identical phenotypes and yet one is struck by lightning and dies, whereas the other lives and reproduces.
This type of drift can play a very important role in the evolution of an organism. However, it is not the only method to evolve. The primary alternative is a process called natural selection, in which the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens argues that there is a big distinction between treating drift as a force or an underlying cause, and treating other causes of evolution such as mutation, selection, and migration as forces or causes. He claims that a causal process explanation of drift allows us to distinguish it from other forces, and this distinction is vital. He also argues that drift has a direction, that is it tends to eliminate heterozygosity, and that it also has a magnitude, that is determined by the size of population.
Evolution through Lamarckism
Students of biology in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution, commonly referred to as “Lamarckism”, states that simple organisms transform into more complex organisms adopting traits that result from the organism's use and misuse. Lamarckism can be demonstrated by a giraffe extending its neck to reach higher branches in the trees. This process would cause giraffes to give their longer necks to offspring, who would then grow even 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 innovative concept that completely challenged the conventional wisdom about organic transformation. According to him, living things had evolved from inanimate matter through the gradual progression of events. Lamarck was not the first to make this claim but he was thought of as the first to give the subject a comprehensive and general overview.
The dominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism were competing during the 19th century. Darwinism ultimately won, leading to what biologists call the Modern Synthesis. The theory argues the possibility that acquired traits can be acquired through inheritance and instead argues that organisms evolve through the selective action of environmental factors, like natural selection.
While Lamarck endorsed the idea of inheritance by acquired characters and his contemporaries offered a few words about this idea, it was never a central element in any of their evolutionary theorizing. This is partly due to the fact that it was never validated scientifically.
It's been more than 200 years since Lamarck was born and, in the age of genomics, there is a large body of evidence supporting the possibility of inheritance of acquired traits. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model.
Evolution by the process of adaptation
One of the most common misconceptions about evolution is being driven by a struggle to survive. In fact, this view is a misrepresentation of natural selection and ignores the other forces that determine the rate of evolution. The struggle for existence is better described as a struggle to survive in a specific environment. This could be a challenge for not just other living things as well as the physical environment itself.
Understanding click the following article is important to understand evolution. It is a feature that allows a living thing to live in its environment and reproduce. It could be a physiological feature, such as feathers or fur or a behavioral characteristic such as a tendency to move into the shade in hot weather or coming out at night to avoid the cold.
The capacity of an organism to extract energy from its environment and interact with other organisms, as well as their physical environments, is crucial to its survival. The organism must have the right genes to create offspring and be able find sufficient food and resources. The organism must be able to reproduce at the rate that is suitable for its specific niche.
These factors, together with mutation and gene flow result in changes in the ratio of alleles (different types of a gene) in the population's gene pool. The change in frequency of alleles can lead to the emergence of new traits, and eventually new species over time.
A lot of the traits we find appealing in animals and plants are adaptations. For instance lung or gills that extract oxygen from the air, fur and feathers as insulation, long legs to run away from predators and camouflage to conceal. However, a complete understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral characteristics.
Physiological adaptations, like thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the desire to find companions or to retreat into the shade in hot weather, are not. In addition, it is important to remember that lack of planning does not make something an adaptation. In fact, failing to consider the consequences of a decision can render it unadaptive, despite the fact that it may appear to be logical or even necessary.