Notes

The Little-Known Benefits Of Free Evolution
What is Free Evolution?

Free evolution is the concept that natural processes can lead to the development of organisms 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 fresh or salt water and walking stick insect varieties that are attracted to specific host plants. These mostly reversible traits permutations are not able to explain fundamental changes to the body's basic plans.

Evolution through Natural Selection

Scientists have been fascinated by the development of all living creatures that live on our planet for ages. The most well-known explanation is that of Charles Darwin's natural selection process, a process that occurs when better-adapted individuals survive 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 cyclical process that is characterized by the interaction of three elements including inheritance, variation, and reproduction. Sexual reproduction and mutation increase the genetic diversity of an animal species. Inheritance is the term used to describe the transmission of a person’s genetic traits, which include recessive and dominant genes, to their offspring. Reproduction is the process of producing fertile, viable offspring. This can be accomplished through sexual or asexual methods.

Natural selection can only occur when all the factors are in harmony. If, for instance the dominant gene allele allows an organism to reproduce and live longer than the recessive allele then the dominant allele is more common in a population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will disappear. This process is self-reinforcing meaning that an organism with a beneficial trait can reproduce and survive longer than an individual with an inadaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the greater number of offspring it produces. People with good traits, such as a longer neck in giraffes and bright white color patterns in male peacocks are more likely to survive and have offspring, so they will make up the majority of the population in the future.

Natural selection is only a force for populations, not on individual organisms. This is a major distinction from the Lamarckian theory of evolution that states that animals acquire traits either through usage or inaction. If a giraffe stretches its neck to catch prey and the neck grows larger, then its offspring will inherit this trait. The length difference between generations will continue until the giraffe's neck becomes so long that it can not breed with other giraffes.

Evolution by Genetic Drift

Genetic drift occurs when alleles from the same gene are randomly distributed within a population. In the end, one will attain fixation (become so widespread that it cannot be removed through natural selection), while other alleles will fall to lower frequency. This could lead to an allele that is dominant in the extreme. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small group it could result in the complete elimination the recessive gene. This scenario is called the bottleneck effect and is typical of an evolution process that occurs when the number of individuals migrate to form a group.

A phenotypic bottleneck can also occur when survivors of a disaster such as an outbreak or a mass hunting event are concentrated in an area of a limited size. The survivors will carry a dominant allele and thus will have the same phenotype. This could be caused by earthquakes, war or even a plague. Regardless of the cause the genetically distinct population that is left might be prone to genetic drift.

Walsh Lewens and Ariew use Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values for different fitness levels. They cite a famous instance of twins who are genetically identical and have identical phenotypes and yet one is struck by lightning and dies, whereas the other lives and reproduces.

This type of drift is very important in the evolution of a species. It is not the only method for evolution. Natural selection is the main alternative, in which mutations and migration maintain the phenotypic diversity in a population.

Stephens claims that there is a significant distinction between treating drift as an actual cause or force, and considering other causes, such as migration and selection as forces and causes. He claims that a causal-process model of drift allows us to differentiate it from other forces and that this differentiation is crucial. He also claims that drift is a directional force: that is it tends to eliminate heterozygosity, and that it also has a specific magnitude that is determined by the size of the population.

Evolution through Lamarckism

Biology students in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, often called "Lamarckism, states that simple organisms transform into more complex organisms by inheriting characteristics that result from the use and abuse of an organism. Lamarckism can be illustrated by a giraffe extending its neck to reach higher levels of leaves in the trees. This process would result in giraffes passing on their longer necks to their offspring, who then get taller.

Lamarck was a French zoologist and, in his opening 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 previous understanding of organic transformation. According to Lamarck, living things evolved from inanimate materials by a series of gradual steps. Lamarck wasn't the only one to propose this, but he was widely considered to be the first to offer the subject a thorough and general explanation.

The popular narrative is that Lamarckism was a rival to Charles Darwin's theory of evolution by natural selection and that the two theories battled it out in the 19th century. Darwinism ultimately won which led to what biologists refer to as the Modern Synthesis. The Modern Synthesis theory denies that acquired characteristics can be inherited and instead argues that organisms evolve through the selective action of environmental factors, like natural selection.

Although Lamarck believed in the concept of inheritance through acquired characters and his contemporaries also spoke of this idea, it was never an integral part of any of their theories about evolution. This is due in part to the fact that it was never validated scientifically.

It has been more than 200 year since Lamarck's birth and in the field of age genomics, there is an increasing body of evidence that supports the heritability acquired characteristics. This is sometimes called "neo-Lamarckism" or more often, epigenetic inheritance. It is a variant of evolution that is as valid as the more well-known neo-Darwinian model.

Evolution by adaptation

One of the most common misconceptions about evolution is that it is driven by a type of struggle to survive. This view misrepresents natural selection and ignores the other forces that determine the rate of evolution. The struggle for survival is more precisely described as a fight to survive in a specific environment, which may include not just other organisms, but as well the physical environment.

Understanding adaptation is important to comprehend evolution. It is a feature that allows a living thing to survive in its environment and reproduce. It can be a physiological feature, like feathers or fur, or a behavioral trait like moving to the shade during hot weather or stepping out at night to avoid cold.


The capacity of an organism to draw energy from its surroundings and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism should possess the right genes to produce offspring, and be able to find enough food and resources. The organism should also be able to reproduce itself at an amount that is appropriate for its particular niche.

These elements, along with gene flow and mutations can result in a shift in the proportion of different alleles within a population’s gene pool. As time passes, this shift in allele frequency can result in the emergence of new traits and ultimately new species.

A lot of the traits we admire in animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, feathers or fur to protect themselves and long legs for running away from predators, and camouflage for hiding. To understand adaptation it is essential to discern between physiological and behavioral traits.

Physiological adaptations, such as the thick fur or gills are physical characteristics, whereas behavioral adaptations, like the tendency to seek out friends or to move to the shade during hot weather, aren't. In addition it is important to understand that a lack of forethought does not make something an adaptation. In fact, failure to think about the consequences of a choice can render it unadaptable, despite the fact that it might appear sensible or even necessary.

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