What is Free Evolution?

Free evolution is the concept that natural processes can lead to the development of organisms over time. This includes the creation of new species and change in appearance of existing ones.

This has been proven by many examples such as the stickleback fish species that can live in salt or fresh water, and walking stick insect types that have a preference for specific host plants. These are mostly reversible traits, however, cannot explain fundamental changes in body plans.

Evolution through Natural Selection

Scientists have been fascinated by the evolution of all the living creatures that live on our planet for many centuries. Charles Darwin's natural selection is the best-established explanation. This process occurs when those who are better adapted have more success in reproduction and survival than those who are less well-adapted. Over time, the population of well-adapted individuals becomes larger and eventually forms 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 a species. Inheritance is the term used to describe the transmission of a person’s genetic characteristics, which includes both dominant and recessive genes, to their offspring. Reproduction is the process of generating fertile, viable offspring. This can be achieved through sexual or asexual methods.

All of these variables must be in harmony to allow natural selection to take place. If, for instance an allele of a dominant gene makes an organism reproduce and last longer than the recessive gene, 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 go away. The process is self-reinforcing, which means that an organism with a beneficial characteristic can reproduce and survive longer than one with an inadaptive characteristic. The higher the level of fitness an organism has which is measured by its ability to reproduce and survive, is the more offspring it can produce. People with good traits, like longer necks in giraffes and bright white color patterns in male peacocks are more likely survive and have offspring, and thus will eventually make up the majority of the population over time.

Natural selection only affects populations, not on individuals. This is a major distinction from the Lamarckian theory of evolution, which argues that animals acquire characteristics through use or disuse. For instance, if the animal's neck is lengthened by stretching to reach prey, its offspring will inherit a more long neck. The differences in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.

Evolution through Genetic Drift

Genetic drift occurs when the alleles of the same gene are randomly distributed in a population. In the end, only one will be fixed (become common enough to no longer be eliminated by natural selection) and the rest of the alleles will decrease in frequency. In the extreme this, it leads to one allele dominance. Other alleles have been basically eliminated and heterozygosity has decreased to a minimum. In a small group, this could result in the complete elimination the recessive gene. This scenario is called the bottleneck effect and is typical of the evolutionary process that occurs when the number of individuals migrate to form a group.

A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe like an outbreak or mass hunt incident are concentrated in the same area. The remaining individuals are likely to be homozygous for the dominant allele which means that they will all have the same phenotype, and thus have the same fitness characteristics. This situation could be caused by earthquakes, war or even a plague. The genetically distinct population, if it remains vulnerable to genetic drift.

Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They cite the famous example of twins who are genetically identical and share the same phenotype, but one is struck by lightning and dies, whereas the other is able to reproduce.

This kind of drift can be vital to the evolution Kr of the species. But, it's not the only method to progress. The main alternative is a process called natural selection, where the phenotypic diversity of a population is maintained by mutation and migration.

Stephens claims that there is a significant difference between treating the phenomenon of drift as an actual cause or force, and treating other causes like migration and selection mutation as causes and forces. Stephens claims that a causal process model of drift allows us to differentiate it from other forces and that this distinction is crucial. He argues further that drift has both an orientation, i.e., it tends to eliminate heterozygosity. It also has a size, that is determined by population size.

Evolution through Lamarckism

When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is commonly called "Lamarckism" and it states that simple organisms develop into more complex organisms through the inheritance of characteristics which result from the organism's natural actions use and misuse. Lamarckism is illustrated through the giraffe's neck being extended to reach higher levels of leaves in the trees. This could cause the longer necks of giraffes to be passed on to their offspring who would grow taller.

Lamarck Lamarck, a French Zoologist, introduced a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate materials through a series gradual steps. Lamarck wasn't the only one to make this claim but he was considered to be the first to offer the subject a thorough and general explanation.

The most popular story is that Charles Darwin's theory on natural selection and Lamarckism fought in the 19th Century. Darwinism eventually prevailed which led to what biologists call the Modern Synthesis. The theory denies that acquired characteristics are passed down from generation to generation and instead, it claims that organisms evolve through the influence of environment factors, such as Natural Selection.

While Lamarck supported the notion of inheritance through acquired characters and his contemporaries also offered a few words about this idea, it was never an integral part of any of their theories about evolution. This is partly because it was never scientifically validated.

It has been more than 200 years since the birth of Lamarck, and in the age genomics, there is an increasing evidence-based body of evidence to support the heritability acquired characteristics. This is also referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a version that is as valid as the popular neodarwinian model.

Evolution through the process of adaptation

One of the most common misconceptions about evolution is being driven by a struggle for survival. This view misrepresents 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 may be a struggle that involves not only other organisms but as well the physical environment.

Understanding the concept of adaptation is crucial to understand evolution. Adaptation is any feature that allows a living thing to live in its environment and reproduce. It could be a physiological structure, such as feathers or fur or a behavioral characteristic like moving to the shade during hot weather or stepping out at night to avoid the cold.

The ability of an organism to draw energy from its surroundings and interact with other organisms as well as their physical environments, is crucial to its survival. The organism must have the right genes to generate offspring, and must be able to find enough food and other resources. Furthermore, the organism needs to be capable of reproducing itself at a high rate within its niche.

These factors, together with gene flow and mutations can result in changes in the proportion of different alleles in a population’s gene pool. As time passes, this shift in allele frequencies can result in the emergence of new traits and eventually new species.

Many of the characteristics we admire about animals and plants are adaptations, like lungs or gills to extract oxygen from the air, feathers or fur to protect themselves long legs to run away from predators, and camouflage for hiding. However, a proper understanding of adaptation requires a keen eye to the distinction between physiological and behavioral characteristics.

Physical traits such as thick fur and gills are physical traits. The behavioral adaptations aren't an exception, for instance, the tendency of animals to seek out companionship or to retreat into the shade in hot temperatures. Furthermore it is important to remember that lack of planning is not a reason to make something an adaptation. Failure to consider the effects of a behavior, even if it appears to be logical, can make it unadaptive.