How Free Evolution Impacted My Life The Better
What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can cause them to develop over time. This includes the development of new species and change in appearance of existing species.
This has been proven by many examples of stickleback fish species that can be found in saltwater or fresh water and walking stick insect species that have a preference for particular host plants. These typically reversible traits are not able to explain fundamental changes to the body's basic plans.
Evolution through Natural Selection
The development of the myriad of living creatures on Earth is an enigma that has fascinated scientists for centuries. Charles Darwin's natural selectivity is the most well-known explanation. This process occurs when those who are better adapted survive and reproduce more than those who are less well-adapted. As time passes, the number of individuals who are well-adapted grows and eventually forms an entirely new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors: variation, reproduction and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity of an animal species. Inheritance refers to the transmission of a person’s genetic traits, including recessive and dominant genes, to their offspring. Reproduction is the process of producing viable, fertile offspring. This can be achieved via sexual or asexual methods.
Natural selection is only possible when all of these factors are in equilibrium. If, for example an allele of a dominant gene causes an organism reproduce and survive more than the recessive allele then the dominant allele is more prevalent in a population. However, if the allele confers an unfavorable survival advantage or decreases fertility, it will disappear from the population. The process is self-reinforcing, which means that the organism with an adaptive characteristic will live and reproduce much more than one with a maladaptive characteristic. The more fit an organism is, measured by its ability reproduce and endure, is the higher number of offspring it will produce. Individuals with favorable characteristics, such as a long neck in the giraffe, or bright white patterns on male peacocks are more likely than others to reproduce and survive, which will eventually lead to them becoming the majority.
Natural selection is a factor in populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution which holds that animals acquire traits either through the use or absence of use. If a giraffe extends its neck in order to catch prey, and the neck becomes larger, then its offspring will inherit this trait. The differences in neck size between generations will increase until the giraffe is unable to reproduce with other giraffes.
Evolution through Genetic Drift
In the process of genetic drift, alleles within a gene can be at different frequencies in a population due to random events. Eventually, only one will be fixed (become widespread enough to not more be eliminated through natural selection) and the other alleles will decrease in frequency. This can result in dominance in the extreme. 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 gene. This is called a bottleneck effect, and it is typical of the kind of evolutionary process that takes place when a lot of people migrate to form a new population.
A phenotypic bottleneck can also occur when survivors of a disaster such as an epidemic or a mass hunting event, are concentrated within a narrow area. The remaining individuals will be mostly homozygous for the dominant allele meaning that they all have the same phenotype and thus have the same fitness traits. This could be caused by earthquakes, war or even a plague. Regardless of the cause, the genetically distinct population that is left might be susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected values due to differences in fitness. They provide the famous case of twins who are both genetically identical and have exactly the same phenotype. However one is struck by lightning and dies, while the other continues to reproduce.
This kind of drift could play a significant role in the evolution of an organism. It's not the only method for evolution. Natural selection is the most common alternative, in which mutations and migrations maintain phenotypic diversity within a population.
Stephens claims that there is a significant difference between treating drift like an actual cause or force, and treating other causes such as migration and selection as forces and causes. He claims that a causal mechanism account of drift permits us to differentiate it from these other forces, and that this distinction is crucial. He further argues that drift has a direction, that is, it tends to eliminate heterozygosity. He also claims that it also has a size, that is determined by the size of population.
Evolution through 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, often referred to as “Lamarckism” is based on the idea that simple organisms transform into more complex organisms by taking on traits that are a product of an organism's use and disuse. Lamarckism can be illustrated by a giraffe extending its neck to reach higher branches in the trees. This could cause giraffes to give their longer necks to their offspring, who then grow even taller.
Lamarck was a French zoologist and, in his lecture to begin his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th of May in 1802, he introduced an innovative concept that completely challenged the previous understanding of organic transformation. According to Lamarck, living things evolved from inanimate materials through a series gradual steps. Lamarck was not the first to suggest that this could be the case but his reputation is widely regarded as giving the subject its first general and comprehensive analysis.
The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were rivals in the 19th Century. Darwinism ultimately prevailed which led to what biologists call the Modern Synthesis. The Modern Synthesis theory denies that traits acquired through evolution can be inherited, and instead argues that organisms evolve through the selective action of environmental factors, such as natural selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed down to future generations. However, this notion was never a key element of any of their theories on evolution. This is partly because it was never scientifically tested.
It's been more than 200 years since Lamarck was born and in the age of genomics, there is a large amount of evidence to support the heritability of acquired characteristics. This is also referred to as "neo Lamarckism", or more generally epigenetic inheritance. This is a variant that is as reliable as the popular neodarwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is that it is driven by a type of struggle for survival. This view is inaccurate and overlooks other forces that drive evolution. The struggle for survival is more precisely described as a fight to survive within a particular environment, which may include not just other organisms, but as well the physical environment.
To understand how evolution works, it is helpful to understand what is adaptation. Adaptation refers to any particular feature that allows an organism to survive and reproduce within its environment. It can be a physiological feature, like feathers or fur or a behavioral characteristic, such as moving into shade in hot weather or coming out at night to avoid the cold.
The capacity of a living thing to extract energy from its environment and interact with other organisms and their physical environment, is crucial to its survival. The organism must have the right genes to produce offspring, and it must be able to find sufficient food and other resources. In addition, the organism should be able to reproduce itself at a high rate within its environmental niche.
These factors, in conjunction with gene flow and mutations can result in a shift in the proportion of different alleles within the gene pool of a population. Over sell , this change in allele frequency can result in the development of new traits, and eventually new species.
Many of the characteristics we admire in animals and plants are adaptations, such as lungs or gills to extract oxygen from the air, feathers or fur to protect themselves long legs to run away from predators, and camouflage to hide. However, a proper understanding of adaptation requires a keen eye to the distinction between behavioral and physiological traits.
Physiological adaptations, such as the thick fur or gills are physical traits, whereas behavioral adaptations, like the tendency to search for friends or to move to the shade during hot weather, aren't. It is important to keep in mind that insufficient planning does not make an adaptation. In fact, a failure to consider the consequences of a behavior can make it unadaptive even though it may appear to be sensible or even necessary.