What is Free Evolution ?
Free evolution is the notion that natural processes can lead to the development of organisms over time. This includes the appearance and development of new species.
Numerous examples have been offered of this, such as different varieties of fish called sticklebacks that can live in fresh or salt water and walking stick insect varieties that are attracted to specific host plants. These mostly reversible traits permutations do not explain the fundamental changes in the body's basic plans.
Evolution by Natural Selection
The evolution of the myriad living organisms on Earth is a mystery that has intrigued scientists for decades. Charles Darwin's natural selection is the most well-known explanation. This process occurs when individuals who are better-adapted are able to reproduce faster and longer 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 a process that is cyclical and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity of an animal species. Inheritance is the term used to describe the transmission of a person's genetic traits, which include both dominant and recessive genes and their offspring. Reproduction is the generation of fertile, viable offspring, which includes both asexual and sexual methods.
All of these elements must be in balance to allow natural selection to take place. If, for instance, a dominant gene allele makes an organism reproduce and survive more than the recessive allele, then the dominant allele will become more common in a population. However, if the allele confers an unfavorable survival advantage or decreases fertility, it will disappear from the population. The process is self-reinforced, meaning that a species that has a beneficial trait will survive and reproduce more than an individual with an unadaptive trait. The more fit an organism is which is measured by its ability to reproduce and survive, is the greater number of offspring it produces. Individuals with favorable traits, such as longer necks in giraffes, or bright white colors in male peacocks, are more likely to survive and produce offspring, and thus will eventually make up the majority of the population over time.
Natural selection only acts on populations, not on individual organisms. This is a significant distinction from the Lamarckian evolution theory which holds that animals acquire traits through use or lack of use. If a giraffe expands its neck in order to catch prey and the neck grows larger, then its children will inherit this characteristic. The difference in neck length between generations will persist until the giraffe's neck becomes too long to no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when alleles of the same gene are randomly distributed within a population. Eventually, one of them will attain fixation (become so common that it can no longer be eliminated through natural selection) and the other alleles drop to lower frequencies. In extreme cases, this leads to a single allele dominance. Other alleles have been virtually eliminated and heterozygosity decreased to a minimum. In a small number of people it could lead to the complete elimination of recessive alleles. This is called a bottleneck effect, and it is typical of evolutionary process when a large number of people migrate to form a new population.
A phenotypic bottleneck may also occur when the survivors of a disaster such as an outbreak or a mass hunting event are concentrated in the same area. The survivors will share an allele that is dominant and will have the same phenotype. This could be caused by earthquakes, war or even plagues. The genetically distinct population, if it is left susceptible to genetic drift.
Walsh, Lewens, and Ariew employ Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any departure from expected values for differences in fitness. They give a famous example of twins that are genetically identical, have identical phenotypes, but one is struck by lightening and dies while the other lives and reproduces.
This kind of drift can play a crucial role in the evolution of an organism. But, it's not the only method to develop. The primary alternative is a process called natural selection, in which the phenotypic variation of a population is maintained by mutation and migration.
Stephens argues there is a vast difference between treating the phenomenon of drift as an actual cause or force, and treating other causes like migration and selection mutation as forces and causes. He claims that a causal-process model of drift allows us to separate it from other forces and that this distinction is essential. He also argues that drift is both a direction, i.e., it tends to eliminate heterozygosity. It also has a size that is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, often referred to as “Lamarckism” which means that simple organisms evolve into more complex organisms by inheriting characteristics that result from the organism's use and misuse. Lamarckism is typically illustrated by the image of a giraffe stretching its neck to reach leaves higher up in the trees. This would cause the longer necks of giraffes to be passed on to their 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 May 1802, he introduced an innovative concept that completely challenged the conventional wisdom about organic transformation. In his opinion, living things had evolved from inanimate matter via a series of gradual steps. Lamarck was not the first to suggest this but he was thought of as the first to offer the subject a comprehensive and general overview.
The predominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th Century. Darwinism eventually won, leading to the development of what biologists 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, such as natural selection.
Lamarck and his contemporaries believed in the notion that acquired characters could be passed down to the next generation. However, this idea was never a major part of any of their evolutionary theories. This is due to the fact that it was never scientifically tested.
It has been more than 200 years since the birth of Lamarck and in the field of age genomics there is a growing evidence-based body of evidence to support the heritability of acquired traits. This is referred to as "neo Lamarckism", or more generally epigenetic inheritance. It is a version of evolution that is just as relevant as the more popular Neo-Darwinian model.
Evolution by adaptation
One of the most commonly-held misconceptions about evolution is that it is being driven by a fight for survival. This view misrepresents natural selection and ignores the other forces that determine the rate of evolution. The struggle for survival is more accurately described as a struggle to survive in a specific environment, which may include not just other organisms but also the physical environment.
Understanding the concept of adaptation is crucial 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 physiological structure such as feathers or fur or a behavioral characteristic, such as moving into the shade in hot weather or stepping out at night to avoid cold.
The survival of an organism depends on its ability to draw energy from the surrounding environment and interact with other organisms and their physical environments. The organism must have the right genes to create offspring and to be able to access sufficient food and resources. The organism should also be able to reproduce at a rate that is optimal for its niche.
These factors, together with gene flow and mutation, lead to a change in the proportion of alleles (different types of a gene) in a population's gene pool. The change in frequency of alleles could lead to the development of novel traits and eventually new species over time.
Many of the characteristics we admire about animals and plants are adaptations, such as the lungs or gills that extract oxygen from the air, fur or feathers to protect themselves, long legs for running away from predators, and camouflage to hide. To understand adaptation it is essential to differentiate between physiological and behavioral traits.
Physical traits such as the thick fur and gills are physical traits. The behavioral adaptations aren't, such as the tendency of animals to seek companionship or retreat into shade in hot temperatures. It is important to keep in mind that lack of planning does not cause an adaptation. A failure to consider the implications of a choice even if it seems to be rational, may make it unadaptive.