15 Documentaries That Are Best About Free Evolution
What is Free Evolution?
Free evolution is the idea that the natural processes of living organisms can lead them to evolve over time. This includes the evolution of new species and the change in appearance of existing ones.
Many examples have been given of this, such as different kinds of stickleback fish that can live in either fresh or salt water and walking stick insect varieties that favor particular host plants. These mostly reversible trait permutations, 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 decades. The most widely accepted explanation is that of Charles Darwin's natural selection process, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those less well adapted. As time passes, a group of well-adapted individuals increases and eventually creates a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity of an animal species. Inheritance is the term used to describe the transmission of a person’s genetic characteristics, which includes recessive and dominant genes and their offspring. Reproduction is the process of producing viable, fertile offspring. This can be accomplished through sexual or asexual methods.
Natural selection can only occur when all the factors are in balance. If, for example the dominant gene allele causes an organism reproduce and survive more than the recessive allele The dominant allele is more prevalent in a group. If the allele confers a negative survival advantage or decreases the fertility of the population, it will disappear. The process is self-reinforcing, which means that an organism that has an adaptive trait will survive and reproduce more quickly than one with a maladaptive characteristic. The greater an organism's fitness which is measured by its ability to reproduce and endure, is the higher number of offspring it produces. People with desirable traits, like the long neck of the giraffe, or bright white color patterns on male peacocks, are more likely than others to live and reproduce, which will eventually lead to them becoming the majority.
Natural selection only affects populations, not on individuals. This is a major distinction from the Lamarckian evolution theory which holds that animals acquire traits due to usage or inaction. If a giraffe stretches its neck to catch prey, and the neck becomes longer, then its offspring will inherit this trait. The difference in neck size between generations will continue to increase until the giraffe is unable to breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, the alleles at a gene may attain different frequencies within a population due to random events. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated by natural selection) and the rest of the alleles will decrease in frequency. This could lead to a dominant allele at the extreme. The other alleles are essentially eliminated and heterozygosity has been reduced to zero. In a small number of people it could result in the complete elimination of recessive gene. This scenario is known as a bottleneck effect and it is typical of the kind of evolutionary process that occurs when a large amount of individuals move to form a new population.
A phenotypic bottleneck could occur when survivors of a disaster like an epidemic or mass hunting event, are concentrated into a small area. The remaining individuals are likely to be homozygous for the dominant allele meaning that they all share the same phenotype and will therefore have the same fitness characteristics. This situation could be caused by war, earthquakes or even plagues. Regardless of the cause, the genetically distinct population that remains is prone to genetic drift.
Walsh, Lewens and Ariew define drift as a departure from the expected value due to differences in fitness. They provide the famous case of twins who are both genetically identical and share the same phenotype. However, one is struck by lightning and dies, but the other continues to reproduce.
This kind of drift could be very important in the evolution of a species. However, it's not the only method to progress. Natural selection is the main alternative, in which mutations and migration keep the phenotypic diversity in a population.
Stephens argues that there is a major distinction between treating drift as a force, or a cause and treating other causes of evolution like selection, mutation, and migration as forces or causes. He argues that a causal process explanation of drift permits us to differentiate it from other forces, and that this distinction is vital. He further argues that drift has both an orientation, i.e., it tends to eliminate heterozygosity. It also has a size which is determined by population size.
Evolution by Lamarckism
When students in high school study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is often referred to as "Lamarckism" and it asserts that simple organisms evolve into more complex organisms via the inherited characteristics that are a result of an organism's natural activities, use and disuse. Lamarckism can be demonstrated by an giraffe's neck stretching to reach higher branches in the trees. This could cause giraffes to give their longer necks to offspring, which then get taller.
Lamarck, a French zoologist, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. In his opinion, living things had evolved from inanimate matter through a series of gradual steps. Lamarck was not the first to suggest that this might be the case but the general consensus is that he was the one being the one who gave the subject its first broad and comprehensive treatment.
website is that Lamarckism grew into a rival to Charles Darwin's theory of evolution through natural selection and both theories battled out in the 19th century. Darwinism eventually triumphed, leading to the development of what biologists now refer to as the Modern Synthesis. This theory denies that acquired characteristics can be inherited 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 concept was never a key element of any of their theories about evolution. This is due in part to the fact that it was never tested scientifically.
It has been more than 200 years since the birth of Lamarck and in the field of genomics there is a growing evidence base that supports the heritability of acquired traits. This is often called "neo-Lamarckism" or, more frequently, epigenetic inheritance. This is a version that is as valid as the popular neodarwinian model.
Evolution through Adaptation
One of the most common misconceptions about evolution is that it is driven by a sort of struggle to survive. This notion is not true and overlooks other forces that drive evolution. The fight for survival can be more effectively described as a struggle to survive in a specific environment, which could include not just other organisms but also the physical environment itself.
Understanding the concept of adaptation is crucial to comprehend evolution. The term "adaptation" refers to any characteristic that allows living organisms to live in its environment and reproduce. It can be a physical structure such as feathers or fur. It could also be a trait of behavior that allows you to move into the shade during hot weather, or moving out to avoid the cold at night.
The capacity of an organism to extract energy from its environment and interact with other organisms as well as their physical environment is essential to its survival. The organism should possess the right genes to produce offspring, and be able to find sufficient food and resources. In addition, the organism should be able to reproduce itself in a way that is optimally within its environmental niche.
These elements, in conjunction with mutation and gene flow can result in a change in the proportion of alleles (different varieties of a particular gene) in the population's gene pool. Over time, this change in allele frequency can lead to the emergence of new traits and ultimately new species.
A lot of the traits we appreciate in animals and plants are adaptations. For example lung or gills that extract oxygen from air feathers and fur as insulation long legs to run away from predators, and camouflage to hide. To understand adaptation it is crucial to distinguish between behavioral and physiological characteristics.
Physical traits such as large gills and thick fur are physical characteristics. Behavior adaptations aren't, such as the tendency of animals to seek out companionship or move into the shade in hot temperatures. Additionally, it is important to understand that a lack of thought is not a reason to make something an adaptation. A failure to consider the consequences of a decision even if it seems to be logical, can make it unadaptive.