What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can lead to their development over time. This includes the creation of new species as well as the alteration of the appearance of existing species.
Numerous examples have been offered of this, such as different kinds of stickleback fish that can live in either fresh or salt water and walking stick insect varieties that are attracted to specific host plants. These are mostly reversible traits however, are not able to explain fundamental changes in basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all living creatures that live on our planet for centuries. Charles Darwin's natural selection is the best-established explanation. This process occurs when individuals who are better-adapted have more success in reproduction and survival than those who are less well-adapted. As time passes, the number of well-adapted individuals becomes larger and eventually creates an entirely new species.
Natural selection is an ongoing process that involves the interaction of three factors: variation, inheritance and reproduction. Mutation and sexual reproduction increase the genetic diversity of a species. Inheritance is the term used to describe the transmission of a person’s genetic traits, including both dominant and recessive genes, to their offspring. Reproduction is the process of generating fertile, viable offspring. This can be accomplished by both asexual or sexual methods.
Natural selection can only occur when all the factors are in harmony. For instance, if an allele that is dominant at a gene allows an organism to live and reproduce more frequently than the recessive allele the dominant allele will become more prevalent within the population. But if the allele confers a disadvantage in survival or decreases fertility, it will be eliminated from the population. The process is self-reinforced, meaning that an organism with a beneficial trait will survive and reproduce more than an individual with a maladaptive characteristic. The more offspring that an organism has the better its fitness, which is measured by its capacity to reproduce itself and survive. Individuals with favorable characteristics, like a longer neck in giraffes, or bright white colors in male peacocks, are more likely to be able to survive and create offspring, which means they will make up the majority of the population over time.
에볼루션코리아 acts on populations, not individual organisms. This is an important distinction from the Lamarckian theory of evolution which claims that animals acquire traits through use or neglect. For instance, if a Giraffe's neck grows longer due to reaching out to catch prey, its offspring will inherit a larger neck. The differences in neck length between generations will continue until the giraffe's neck gets too long that it can no longer breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles of a gene could reach different frequencies in a group through random events. Eventually, only one will be fixed (become widespread enough to not longer be eliminated through natural selection) and the other alleles will drop in frequency. In extreme cases this, it leads to dominance of a single allele. The other alleles are basically eliminated and heterozygosity has diminished to zero. In a small number of people, this could lead to the complete elimination of recessive allele. This is known as the bottleneck effect. It is typical of the evolutionary process that occurs when a large number individuals migrate to form a population.
A phenotypic bottleneck may occur when the survivors of a catastrophe like an epidemic or a mass hunting event, are concentrated in a limited area. The surviving individuals are likely to be homozygous for the dominant allele which means that they will all have the same phenotype, and thus share the same fitness characteristics. This could be the result of a war, earthquake or even a disease. The genetically distinct population, if it remains susceptible to genetic drift.
Walsh Lewens, Walsh 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 genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, but the other is able to reproduce.
This kind of drift can be vital to the evolution of an entire species. However, it's not the only method to progress. The primary alternative is a process known as natural selection, where the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens argues that there is a significant difference between treating the phenomenon of drift as a force or a cause and treating other causes of evolution like mutation, selection and migration as causes or causes. He claims that a causal process account of drift permits us to differentiate it from other forces, and this distinction is vital. He further argues that drift is a directional force: that is it tends to eliminate heterozygosity. It also has a magnitude, which is determined by the size of the population.
Evolution through Lamarckism
In high school, students study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is often called "Lamarckism" and it asserts that simple organisms evolve into more complex organisms by the inherited characteristics that result from an organism's natural activities use and misuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher leaves in the trees. This would cause giraffes to pass on their longer necks to their offspring, who would then grow even taller.
Lamarck the French zoologist, presented an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged previous thinking on organic transformation. In his view, living things had evolved from inanimate matter through a series of gradual steps. Lamarck was not the first to make this claim but he was regarded as the first to give the subject a thorough and general treatment.
The dominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th Century. Darwinism ultimately won and led to what biologists call the Modern Synthesis. This theory denies that traits acquired through evolution can be acquired through inheritance and instead argues that organisms evolve through the selective action of environmental factors, such as natural selection.
Lamarck and his contemporaries supported the notion that acquired characters could be passed down to the next generation. However, this idea was never a central part of any of their evolutionary theories. This is due to the fact that it was never tested scientifically.
It's been more than 200 year since Lamarck's birth and in the field of genomics, there is a growing body of evidence that supports the heritability acquired characteristics. This is also referred to as "neo Lamarckism", or more generally epigenetic inheritance. This is a model that is just as valid as the popular Neodarwinian model.
Evolution by Adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle to survive. This view is inaccurate and overlooks other forces that drive evolution. The fight for survival can be more precisely described as a fight to survive within a particular environment, which could involve not only other organisms, but also the physical environment itself.
To understand how evolution functions it is beneficial to consider what adaptation is. The term "adaptation" refers to any specific feature that allows an organism to live and reproduce within its environment. It could be a physical feature, such as feathers or fur. It could also be a behavior trait such as moving into the shade during hot weather or moving out to avoid the cold at night.
An organism's survival depends on its ability to obtain energy from the surrounding environment and interact with other living organisms and their physical surroundings. The organism should possess the right genes to produce offspring and be able find sufficient food and resources. The organism should also be able reproduce itself at the rate that is suitable for its specific niche.
These factors, together with gene flow and mutations can result in a shift in the proportion of different alleles in a population’s gene pool. As time passes, this shift in allele frequencies can lead to the emergence of new traits and eventually new species.
A lot of the traits we admire in plants and animals are adaptations. For instance, lungs or gills that extract oxygen from the air feathers and fur for insulation and long legs to get away from predators and camouflage for hiding. However, a proper understanding of adaptation requires paying attention to the distinction between physiological and behavioral characteristics.
Physiological adaptations, such as the thick fur or gills are physical traits, whereas behavioral adaptations, such as the desire to find companions or to move to shade in hot weather, are not. It is important to remember that a insufficient planning does not make an adaptation. A failure to consider the effects of a behavior even if it appears to be rational, may cause it to be unadaptive.