15 Documentaries That Are Best About Free Evolution

What is Free Evolution?

Free evolution is the idea that natural processes can cause organisms to evolve over time. This includes the development of new species and the transformation of the appearance of existing species.

A variety of examples have been provided of this, including different kinds of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that are attracted to particular host plants. These reversible traits, however, cannot explain fundamental changes in body plans.

Evolution by Natural Selection

The development of the myriad living organisms on Earth is an enigma that has intrigued scientists for centuries. The best-established explanation is that of Charles Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those who are less well-adapted. Over time, a population of well-adapted individuals expands and eventually forms a whole new species.

Natural selection is a process that is cyclical and involves the interaction of 3 factors: variation, reproduction and inheritance. Mutation and sexual reproduction increase the genetic diversity of the species. Inheritance is the transfer of a person's genetic characteristics to his or her offspring, which includes both dominant and recessive alleles. Reproduction is the process of generating viable, fertile offspring. This can be achieved through sexual or asexual methods.

All of these factors must be in harmony for natural selection to occur. If, for example an allele of a dominant gene causes an organism reproduce and live longer than the recessive gene then the dominant allele becomes more prevalent in a population. If the allele confers a negative survival advantage or lowers the fertility of the population, it will go away. The process is self-reinforcing, meaning that an organism with a beneficial trait is more likely to survive and reproduce than an individual with an unadaptive trait. The more fit an organism is, measured by its ability reproduce and survive, is the greater number of offspring it can produce. People with good traits, like the long neck of the giraffe, or bright white color patterns on male peacocks are more likely to others to survive and reproduce, which will eventually lead to them becoming the majority.

Natural selection only affects populations, not individual organisms. This is a major distinction from the Lamarckian evolution theory which holds that animals acquire traits through use or lack of use. If a giraffe extends its neck to reach prey, and the neck becomes larger, then its children will inherit this characteristic. The differences in neck length between generations will persist until the giraffe's neck becomes too long that it can no longer breed with other giraffes.

Evolution by Genetic Drift

Genetic drift occurs when alleles of a gene are randomly distributed in a population. In the end, one will reach fixation (become so common that it is unable to be removed through natural selection), while other alleles fall to lower frequency. In extreme cases, this leads to dominance of a single allele. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small group this could result in the complete elimination of the recessive allele. This is known as a bottleneck effect and it is typical of evolutionary process that takes place when a large number of individuals migrate to form a new population.

A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe such as an outbreak or mass hunt event are concentrated in an area of a limited size. The surviving individuals are likely to be homozygous for the dominant allele which means they will all share the same phenotype and will consequently have the same fitness characteristics. This situation might be the result of a war, an earthquake, or even a plague. Whatever the reason the genetically distinct group that remains could be susceptible to genetic drift.

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

This kind of drift can play a very important part in the evolution of an organism. However, it is not the only way to develop. Natural selection is the main alternative, in which mutations and migration maintain phenotypic diversity within the population.

Stephens claims that there is a vast difference between treating the phenomenon of drift as an actual cause or force, and considering other causes, such as selection mutation and migration as causes and forces. He claims that a causal mechanism account of drift permits us to differentiate it from the other forces, and that this distinction is crucial. He further argues that drift has a direction: that is it tends to reduce heterozygosity. It also has a size, which is determined by the size of the population.

Evolution through Lamarckism

When high school students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, often referred to as "Lamarckism, states that simple organisms develop into more complex organisms taking on traits that result from an organism's use and disuse. Lamarckism can be demonstrated by a giraffe extending its neck to reach higher leaves in the trees. This causes the longer necks of giraffes to be passed on to their offspring who would then grow even 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 of May in 1802, he presented a groundbreaking concept that radically challenged previous thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate materials by a series of gradual 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 general and comprehensive analysis.

The most popular story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were rivals during the 19th century. Darwinism ultimately prevailed and led to what biologists refer to as the Modern Synthesis. The theory argues the possibility that acquired traits can be acquired through inheritance and instead argues that organisms evolve through the action of environmental factors, like natural selection.

Although Lamarck supported the notion of inheritance through acquired characters and his contemporaries also spoke of this idea however, it was not a major feature in any of their theories about evolution. This is due to the fact that it was never scientifically validated.

It has been more than 200 year since Lamarck's birth and in the field of 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 generally epigenetic inheritance. It is a form of evolution that is as relevant as the more popular neo-Darwinian model.

Evolution by adaptation

One of the most common misconceptions about evolution is its being driven by a fight for survival. In reality, this notion is inaccurate and overlooks the other forces that are driving evolution. The fight for survival is better described as a fight to survive in a certain environment. This may be a challenge for not just other living things, but also the physical surroundings themselves.

Understanding adaptation is important 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 fur or feathers or a behavioral characteristic, such as moving to the shade during hot weather or coming out at night to avoid the cold.

An organism's survival depends on its ability to draw energy from the environment and interact with other living organisms and their physical surroundings. The organism must have the right genes to create offspring and be able find sufficient food and resources. In addition, the organism should be capable of reproducing at an optimal rate within its niche.

These factors, along with mutation and gene flow can result in a change in the proportion of alleles (different forms of a gene) in the gene pool of a population. This change in allele frequency can lead to the emergence of new traits and eventually, new species as time passes.

Many of the characteristics we appreciate in animals and plants are adaptations. For example the lungs or gills which extract oxygen from air, fur and feathers as insulation and long legs to get away from predators, and camouflage to hide. To comprehend adaptation it is essential to differentiate between physiological and behavioral characteristics.

Physical characteristics like large gills and thick fur are physical traits. Behavioral adaptations are not an exception, for instance, the tendency of animals to seek companionship or retreat into shade in hot temperatures. It is also important to remember that a insufficient planning does not cause an adaptation.  evolutionkr  to think about the effects of a behavior, even if it appears to be logical, can make it unadaptive.