What is Free Evolution?
Free evolution is the idea that the natural processes of organisms can lead to their development over time. This includes the evolution of new species and transformation of the appearance of existing species.
Many examples have been given of this, such as different varieties of fish called sticklebacks that can live in either salt or fresh water, as well as walking stick insect varieties that are attracted to specific host plants. These reversible traits can't, however, explain fundamental changes in body plans.
Evolution through Natural Selection
The evolution of the myriad living creatures on Earth is an enigma that has fascinated scientists for decades. The most widely accepted explanation is Charles Darwin's natural selection, which occurs when better-adapted individuals survive and reproduce more successfully than those that are less well-adapted. Over time, a community of well-adapted individuals increases and eventually becomes a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction, both of which increase the genetic diversity within an animal species. Inheritance is the passing of a person's genetic traits to their offspring, which includes both recessive and dominant alleles. Reproduction is the production of fertile, viable offspring, which includes both sexual and asexual methods.
All of these elements must be in harmony to allow natural selection to take place. For example the case where a dominant allele at a gene allows an organism to live and reproduce more frequently than the recessive one, the dominant allele will be more prominent in the population. If the allele confers a negative survival advantage or reduces the fertility of the population, it will go away. The process is self reinforcing, which means that the organism with an adaptive trait will live and reproduce far more effectively than those with a maladaptive trait. The more offspring an organism produces the better its fitness that is determined by its ability to reproduce and survive. People with good characteristics, such as having a long neck in the giraffe, or bright white color patterns on male peacocks, are more likely than others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection only affects populations, not individuals. This is a significant distinction from the Lamarckian theory of evolution which argues that animals acquire traits by use or inactivity. If a giraffe extends its neck in order to catch prey and its neck gets larger, then its children will inherit this characteristic. 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 the process of genetic drift, alleles within a gene can be at different frequencies within a population by chance events. At some point, one will reach fixation (become so widespread that it cannot be eliminated by natural selection), while other alleles fall to lower frequencies. This can lead to dominance in extreme. Other alleles have been virtually eliminated and heterozygosity diminished to zero. In a small group it could lead to the total elimination of the recessive allele. This is known as the bottleneck effect and is typical of an evolutionary process that occurs when an enormous number of individuals move to form a group.
A phenotypic bottleneck can also occur when survivors of a disaster such as an outbreak or mass hunting event are concentrated in an area of a limited size. The survivors will have a dominant allele and thus will have the same phenotype. This could be caused by war, an earthquake, or even a plague. Regardless of 에볼루션 무료체험 , the genetically distinct population that remains could be prone to genetic drift.
Walsh, Lewens and Ariew define drift as a departure from expected values due to differences in fitness. They provide a well-known instance of twins who are genetically identical and have the exact same phenotype and yet one is struck by lightning and dies, whereas the other lives and reproduces.
This type of drift is vital to the evolution of an entire species. However, it is not the only method to progress. The main alternative is a process called natural selection, in which phenotypic variation in an individual is maintained through mutation and migration.
에볼루션 무료체험 asserts that there is a vast distinction between treating drift as a force or cause, and treating other causes like migration and selection 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 vital. He argues further that drift has both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined based on the size of the population.
Evolution through Lamarckism
Biology students in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, often referred to as “Lamarckism” is based on the idea that simple organisms develop into more complex organisms by adopting traits that result from an organism's use and disuse. Lamarckism can be demonstrated by the giraffe's neck being extended to reach higher leaves in the trees. This causes the necks of giraffes that are longer to be passed onto their offspring who would then become taller.
Lamarck was a French zoologist and, in his opening lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th May 1802, he presented an innovative concept that completely challenged the previous understanding of organic transformation. According to Lamarck, living things evolved from inanimate material through a series gradual steps. Lamarck wasn't the first to propose this, but he was widely considered to be the first to offer the subject a comprehensive and general treatment.
The predominant story is that Charles Darwin's theory on evolution by natural selection and Lamarckism fought in the 19th Century. Darwinism eventually prevailed, leading to what biologists call the Modern Synthesis. The theory argues the possibility that acquired traits can be inherited and instead, it argues that organisms develop through the action of environmental factors, such as natural selection.
Although Lamarck believed in the concept of inheritance by acquired characters, and his contemporaries also offered a few words about this idea, it was never a central element in any of their evolutionary theorizing. This is partly because it was never scientifically validated.
It's been over 200 years since the birth of Lamarck and in the field of age genomics there is a growing evidence base that supports the heritability-acquired characteristics. It is sometimes called "neo-Lamarckism" or more commonly, epigenetic inheritance. This is a model that is just as valid as the popular neodarwinian model.
Evolution by Adaptation
One of the most common misconceptions about evolution is that it is driven by a type of struggle to survive. This is a false assumption and overlooks other forces that drive evolution. The struggle for existence is better described as a struggle to survive in a specific environment. This could be a challenge for not just other living things, but also the physical environment itself.
Understanding the concept of adaptation is crucial to understand evolution. It refers to a specific characteristic that allows an organism to live and reproduce in its environment. It could be a physiological structure such as feathers or fur or a behavior such as a tendency to move to the shade during the heat or leaving at night to avoid cold.
The survival of an organism depends on its ability to obtain energy from the environment and interact with other living organisms and their physical surroundings. The organism must have the right genes to produce offspring, and it must be able to locate enough food and other resources. In addition, the organism should be able to reproduce itself in a way that is optimally within its environment.
These factors, in conjunction with mutations and gene flow can cause an alteration in the ratio of different alleles within the population's gene pool. Over time, this change in allele frequencies could result in the emergence of new traits, and eventually new species.
A lot of the traits we admire in plants and animals are adaptations. For instance the lungs or gills which extract oxygen from the air feathers and fur as insulation and long legs to get away from predators and camouflage to conceal. However, a complete understanding of adaptation requires a keen eye to the distinction between the physiological and behavioral traits.
Physiological traits like thick fur and gills are physical characteristics. Behavior adaptations aren't like the tendency of animals to seek companionship or retreat into shade in hot weather. It is important to keep in mind that lack of planning does not make an adaptation. A failure to consider the implications of a choice even if it seems to be rational, could make it unadaptive.