What is Free Evolution?
Free evolution is the concept that natural processes can cause organisms to develop over time. This includes the appearance and development of new species.
This has been proven by many examples such as the stickleback fish species that can thrive in saltwater or fresh water and walking stick insect species that have a preference for specific host plants. These mostly reversible traits permutations do not explain the fundamental changes in basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the evolution of all the living organisms that inhabit our planet for centuries. The most well-known explanation is Charles Darwin's natural selection process, which occurs when better-adapted individuals survive and reproduce more effectively than those less well adapted. Over time, a population of well-adapted individuals increases and eventually becomes a new species.
Natural selection is an ongoing process that involves the interaction of three factors including inheritance, variation, and reproduction. Mutation and sexual reproduction increase genetic diversity in an animal species. Inheritance is the passing of a person's genetic characteristics to their offspring, which includes both dominant and recessive alleles. Reproduction is the production of viable, fertile offspring, which includes both sexual and asexual methods.
All of these variables must be in harmony to allow natural selection to take place. For example when a dominant allele at one gene can cause an organism to live and reproduce more often than the recessive allele the dominant allele will become more common in the population. However, if the gene confers a disadvantage in survival or decreases fertility, it will be eliminated from the population. This process is self-reinforcing which means that an organism that has a beneficial trait can reproduce and survive longer than one with an unadaptive trait. The more offspring that an organism has the better its fitness which is measured by its ability to reproduce itself and survive. People with good characteristics, like a longer neck in giraffes, or bright white colors in male peacocks, are more likely to survive and have offspring, which means they will become the majority of the population over time.
Natural selection is only an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution, which states that animals acquire traits through usage or inaction. For example, if a Giraffe's neck grows longer due to reaching out to catch prey and its offspring will inherit a longer neck. The differences in neck length between generations will persist until the giraffe's neck gets too long to no longer breed with other giraffes.
Evolution by Genetic Drift
Genetic drift occurs when the alleles of the same gene are randomly distributed in a population. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated through natural selection), and the other alleles drop in frequency. This can lead to dominance in extreme. The other alleles have been essentially eliminated and heterozygosity has decreased to zero. In a small number of people it could result in the complete elimination of the recessive gene. This scenario is called the bottleneck effect and is typical of the evolution process that occurs when the number of individuals migrate to form a population.
A phenotypic bottleneck can also occur when the survivors of a disaster like an outbreak or mass hunt event are concentrated in a small area. The remaining individuals will be mostly homozygous for the dominant allele, which means that they will all share the same phenotype and therefore have the same fitness traits. This may be caused by a war, an earthquake, or even a plague. Whatever the reason the genetically distinct population that remains is susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a deviation from the expected value due to differences in fitness. They cite the famous example of twins who are both genetically identical and share the same phenotype, but one is struck by lightning and dies, whereas the other continues to reproduce.
This type of drift is very important in the evolution of the species. However, it's not the only method to progress. The primary alternative is to use a process known as natural selection, where the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens argues there is a significant distinction between treating drift as an agent or cause and considering other causes, such as selection mutation and migration as causes and forces. Stephens claims that a causal mechanism account of drift allows us to distinguish it from the other forces, and this distinction is essential. He further argues that drift has a direction, that is it tends to reduce heterozygosity. It also has a magnitude, which is determined by the size of the population.
Evolution through Lamarckism
Students of biology in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is often called "Lamarckism" and it states that simple organisms develop into more complex organisms through the inheritance of characteristics that are a result of the natural activities of an organism use and misuse. Lamarckism is illustrated through a giraffe extending its neck to reach higher branches in the trees. This causes giraffes' longer necks to be passed on to their offspring who would then become taller.
Lamarck was a French Zoologist. In his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th of May in 1802, he presented an innovative concept that completely challenged previous thinking about organic transformation. In his opinion living things evolved from inanimate matter through a series of gradual steps. Lamarck was not the only one to suggest that this might be the case, but he is widely seen as giving the subject his first comprehensive and thorough treatment.
The most popular story is that Charles Darwin's theory on evolution by natural selection and Lamarckism were competing during the 19th century. Darwinism eventually prevailed which led to what biologists call the Modern Synthesis. This theory denies acquired characteristics can be passed down and instead argues organisms evolve by the influence of environment elements, like Natural Selection.
Although Lamarck supported the notion of inheritance through acquired characters, and his contemporaries also spoke of this idea, it was never a major feature in any of their evolutionary theories. This is due to the fact that it was never scientifically validated.
It has been more than 200 years since the birth of Lamarck and in the field of genomics, there is a growing evidence-based body of evidence to support the heritability of acquired traits. This is sometimes referred to as "neo-Lamarckism" or more commonly, epigenetic inheritance. It is a form of evolution that is as valid as the more well-known Neo-Darwinian theory.
Evolution through the process of adaptation
One of the most popular misconceptions about evolution is being driven by a struggle to survive. In reality, this notion is inaccurate and overlooks the other forces that drive evolution. The struggle for survival is more precisely described as a fight to survive within a specific environment, which could involve not only other organisms, but also the physical environment itself.
To understand how evolution works, it is helpful to consider what adaptation is. The term "adaptation" refers to any characteristic that allows a living organism to live in its environment and reproduce. It could be a physiological feature, such as fur or feathers or a behavioral characteristic, such as moving to the shade during the heat or leaving at night to avoid the cold.
The capacity of an organism to extract energy from its environment and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism should possess the right genes to produce offspring and be able find enough food and resources. Furthermore, the organism needs to be able to reproduce itself in a way that is optimally within its niche.
These elements, along with gene flow and mutations, can lead to an alteration in the ratio of different alleles within a population’s gene pool. As 에볼루션 무료체험 , this shift in allele frequencies can lead to the emergence of new traits, and eventually new species.
Many of the characteristics we appreciate in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from air feathers and fur for insulation long legs to run away from predators and camouflage to conceal. To understand the concept of adaptation, it is important to differentiate between physiological and behavioral characteristics.
Physiological adaptations like the thick fur or gills are physical characteristics, whereas behavioral adaptations, such as the tendency to search for companions or to move into the shade in hot weather, are not. It is also important to keep in mind that lack of planning does not cause an adaptation. In fact, a failure to consider the consequences of a choice can render it unadaptable even though it may appear to be reasonable or even essential.