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What is Free Evolution?

Free evolution is the notion that the natural processes of living organisms can lead to their development over time. This includes the evolution of new species as well as the change in appearance of existing ones.

A variety of examples have been provided of this, including different varieties of stickleback fish that can live in salt or fresh water, and walking stick insect varieties that favor particular host plants. These mostly reversible traits permutations cannot explain fundamental changes to the basic body plan.

Evolution through Natural Selection

The development of the myriad of living organisms on Earth is an enigma that has intrigued scientists for decades. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when those who are better adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, the number of well-adapted individuals becomes larger and eventually develops into an entirely new species.

Natural selection is a process that is cyclical and involves the interaction of three factors: variation, reproduction and inheritance. Sexual reproduction and mutations increase the genetic diversity of the species. Inheritance is the passing of a person's genetic traits to the offspring of that person, which includes both dominant and recessive alleles. Reproduction is the production of viable, fertile offspring, which includes both asexual and sexual methods.

All of these factors must be in harmony for natural selection to occur. For instance the case where the dominant allele of the gene allows an organism to live and reproduce more often than the recessive allele, the dominant allele will be more prevalent within the population. But if the allele confers a disadvantage in survival or decreases fertility, it will disappear from the population. The process is self-reinforced, which means that an organism with a beneficial trait will survive and reproduce more than one with an unadaptive trait. The more offspring that an organism has the better its fitness, which is measured by its ability to reproduce itself and live. Individuals with favorable traits, like longer necks in giraffes and bright white color patterns in male peacocks, are more likely to survive and have offspring, which means they will eventually make up the majority of the population in the future.

Natural selection is only a force for populations, not individuals. This is an important distinction from the Lamarckian theory of evolution which argues that animals acquire traits by use or inactivity. For instance, if the Giraffe's neck grows longer due to stretching to reach for prey, its offspring will inherit a longer neck. The difference in neck size between generations will continue to grow until the giraffe is no longer able to breed with other giraffes.

Evolution through Genetic Drift

Genetic drift occurs when alleles of one gene are distributed randomly in a group. At some point, only one of them will be fixed (become common enough that it can no more be eliminated through natural selection) and the rest of the alleles will diminish in frequency. In extreme cases this, it leads to dominance of a single allele. 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 gene. This scenario is known as a bottleneck effect and it is typical of evolutionary process that occurs when a large number of individuals move to form a new group.

A phenotypic bottleneck can also occur when survivors of a catastrophe such as an epidemic or a mass hunting event, are condensed in a limited area. The remaining individuals will be largely homozygous for the dominant allele which means that they will all share the same phenotype and consequently share the same fitness characteristics. This may be caused by a war, an earthquake or even a disease. The genetically distinct population, if it remains vulnerable to genetic drift.

Walsh, Lewens and Ariew define drift as a deviation from the expected value due to differences in fitness. They provide the famous case of twins who are both genetically identical and have exactly the same phenotype. However, ???? ?????? is struck by lightning and dies, whereas the other lives to reproduce.

This type of drift is vital to the evolution of the species. This isn't the only method of evolution. The main alternative is a process known as natural selection, in which the phenotypic variation of an individual is maintained through 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 such as migration and selection as causes and forces. He argues that a causal process account of drift permits us to differentiate it from these other forces, and this distinction is crucial. He argues further that drift is both direction, i.e., it tends towards eliminating heterozygosity. It also has a size that is determined by the size of the population.

Evolution by Lamarckism

When students in high school take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is generally called "Lamarckism" and it asserts that simple organisms evolve into more complex organisms through the inheritance of traits that result from the natural activities of an organism use and misuse. Lamarckism is typically illustrated with the image of a giraffe stretching its neck longer to reach higher up in the trees. This would cause the longer necks of giraffes to be passed on to their offspring who would then become taller.

Lamarck was a French Zoologist. In his opening 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 previous thinking about organic transformation. According to him living things evolved from inanimate matter through an escalating series of steps. Lamarck was not the first to suggest that this could be the case, but he is widely seen as being the one who gave the subject its first broad and comprehensive analysis.

The dominant story is that Charles Darwin's theory on natural selection and Lamarckism were rivals in the 19th Century. Darwinism eventually triumphed and led to the creation of what biologists now call the Modern Synthesis. The theory argues that acquired characteristics can be acquired through inheritance and instead argues that organisms evolve through the action of environmental factors, including natural selection.

Lamarck and his contemporaries believed in the idea that acquired characters could be passed on to the next generation. However, this idea was never a key element of any of their theories on evolution. This is partly due 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 genomics, there is a large amount of evidence to support the possibility of inheritance of acquired traits. This is also referred to as "neo Lamarckism", or more often epigenetic inheritance. It is a form of evolution that is as valid as the more well-known Neo-Darwinian theory.

Evolution by Adaptation

One of the most common misconceptions about evolution is that it is a result of a kind of struggle to survive. This view misrepresents natural selection and ignores the other forces that are driving evolution. The fight for survival can be more precisely described as a fight to survive within a particular environment, which may include not just other organisms, but also the physical environment.

Understanding the concept of adaptation is crucial to comprehend evolution. Adaptation refers to any particular feature that allows an organism to survive and reproduce in its environment. It can be a physical structure such as feathers or fur. Or it can be a characteristic of behavior that allows you to move into the shade during the heat, or moving out to avoid the cold at night.

The survival of an organism depends on its ability to extract energy from the surrounding environment and interact with other organisms and their physical environments. The organism should possess the right genes to produce offspring, and be able to find sufficient food and resources. Furthermore, the organism needs to be able to reproduce itself in a way that is optimally within its environmental niche.

These elements, along with gene flow and mutations, can lead to an alteration in the ratio of different alleles within the population's gene pool. This change in allele frequency could lead to the development of novel traits and eventually new species as time passes.

Many of the characteristics we appreciate in plants and animals are adaptations. For instance, lungs or gills that extract oxygen from air, fur and feathers as insulation, long legs to run away from predators and camouflage to conceal. To understand the concept of adaptation it is essential to discern between physiological and behavioral traits.


Physiological adaptations like thick fur or gills are physical traits, while behavioral adaptations, like the tendency to seek out companions or to move to the shade during hot weather, aren't. It is important to remember that a lack of planning does not cause an adaptation. In fact, a failure to consider the consequences of a choice can render it unadaptable even though it might appear sensible or even necessary.

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