What is Free Evolution?
Free evolution is the idea that the natural processes of living organisms can cause them to develop over time. This includes the development of new species and the alteration of the appearance of existing ones.
This has been proven by numerous examples such as the stickleback fish species that can thrive in saltwater or fresh water and walking stick insect types that prefer particular host plants. These reversible traits can't, however, explain fundamental changes in body plans.
Evolution through Natural Selection
The development of the myriad of living organisms on Earth is an enigma that has fascinated scientists for centuries. 에볼루션 무료 바카라 -known explanation is Darwin's natural selection, which is triggered when more well-adapted individuals live longer and reproduce more successfully than those who are less well adapted. Over time, the population of individuals who are well-adapted grows and eventually creates an entirely new species.
Natural selection is a cyclical process that involves the interaction of three elements that are inheritance, variation and reproduction. Sexual reproduction and mutations increase genetic diversity in an animal species. Inheritance refers to the transmission of genetic traits, which include recessive and dominant genes, to their offspring. Reproduction is the production of fertile, viable offspring which includes both asexual and sexual methods.
Natural selection is only possible when all of these factors are in harmony. For instance, if a dominant allele at a gene causes an organism to survive and reproduce more frequently than the recessive allele, the dominant allele will become more common in the population. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will be eliminated. This process is self-reinforcing meaning that an organism that has a beneficial trait is more likely to survive and reproduce than an individual with a maladaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the more offspring it will produce. People with good traits, such as a longer neck in giraffes, or bright white colors in male peacocks, are more likely to be able to survive and create offspring, and thus will eventually make up the majority of the population over time.
Natural selection only affects populations, not on individuals. This is a significant distinction from the Lamarckian theory of evolution which states that animals acquire characteristics through use or disuse. For instance, if the giraffe's neck gets longer through stretching to reach for prey its offspring will inherit a more long neck. The differences in neck length between generations will persist until the neck of the giraffe becomes too long to not breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, the alleles within a gene can be at different frequencies in a group by chance events. In the end, only one will be fixed (become common enough to no more be eliminated through natural selection) and the other alleles will diminish in frequency. This can result in a dominant allele in extreme. The other alleles are eliminated, and heterozygosity decreases to zero. In a small population it could result in the complete elimination of recessive gene. This scenario is called the bottleneck effect. It is typical of the evolutionary process that occurs when an enormous number of individuals move to form a population.
A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe like an outbreak or a mass hunting incident are concentrated in the same area. The survivors will have a dominant allele and thus will have the same phenotype. This could be caused by a war, earthquake or even a cholera outbreak. Whatever the reason the genetically distinct population that remains could be susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew utilize Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values of differences in fitness. They provide a well-known example of twins that are genetically identical and have the exact same phenotype and yet one is struck by lightening and dies while the other lives and reproduces.
This kind of drift can be crucial in the evolution of an entire species. It's not the only method of evolution. Natural selection is the primary alternative, in which mutations and migration keep the phenotypic diversity in the population.
Stephens argues there is a vast difference between treating the phenomenon of drift as a force or cause, and treating other causes such as selection mutation and migration as causes and forces. He claims that a causal-process account of drift allows us distinguish it from other forces and that this differentiation is crucial. He also claims that drift has a direction: that is it tends to reduce heterozygosity, and that it also has a specific magnitude which is determined by the size of population.
Evolution by Lamarckism
Students of biology in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is generally known as "Lamarckism" and it asserts that simple organisms evolve into more complex organisms via the inheritance of traits that are a result of the natural activities of an organism use and misuse. Lamarckism is usually illustrated with the image of a giraffe stretching its neck to reach leaves higher up in the trees. This causes the necks of giraffes that are longer to be passed to their offspring, who would then grow even taller.
Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged traditional thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate material through a series gradual steps. Lamarck was not the only one 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.
The prevailing story is that Lamarckism became an opponent to Charles Darwin's theory of evolution by natural selection and that the two theories battled out in the 19th century. Darwinism eventually won and led to the development of what biologists call the Modern Synthesis. This theory denies acquired characteristics can be passed down through generations and instead argues that organisms evolve through the selective influence of environmental factors, such as Natural Selection.
Lamarck and his contemporaries supported the notion that acquired characters could be passed down to future generations. However, this idea was never a key element of any of their theories about evolution. This is largely due to the fact that it was never validated scientifically.
It's been more than 200 years since Lamarck was born and in the age genomics there is a huge amount of evidence to support the heritability of acquired traits. This is referred to as "neo Lamarckism", or more commonly epigenetic inheritance. It is a form of evolution that is just as valid as the more popular Neo-Darwinian theory.
Evolution by Adaptation
One of the most commonly-held misconceptions about evolution is being driven by a struggle for survival. In fact, this view misrepresents natural selection and ignores the other forces that are driving evolution. The fight for survival can be more precisely described as a fight to survive in a specific environment, which could be a struggle that involves not only other organisms, but also the physical environment.
To understand how evolution operates it is important to consider what adaptation is. Adaptation refers to any particular characteristic that allows an organism to live and reproduce in its environment. It can be a physiological structure, such as fur or feathers or a behavioral characteristic such as a tendency to move into the shade in the heat or leaving at night to avoid cold.
The capacity of a living thing to extract energy from its surroundings and interact with other organisms and their physical environment, is crucial to its survival. The organism must possess the right genes to create offspring, and it must be able to access enough food and other resources. Furthermore, the organism needs to be capable of reproducing in a way that is optimally within its environmental niche.
These elements, along with mutations and gene flow, can lead to changes in the proportion of different alleles in the population's gene pool. This change in allele frequency could lead to the development of novel traits and eventually new species over time.
A lot of the traits we admire in animals and plants are adaptations, such as lung or gills for removing oxygen from the air, feathers or fur to protect themselves, long legs for running away from predators and camouflage for hiding. To understand the concept of adaptation it is essential to discern between physiological and behavioral characteristics.
Physical traits such as thick fur and gills are physical characteristics. Behavioral adaptations are not, such as the tendency of animals to seek companionship or retreat into shade in hot weather. It is also important to note that the absence of planning doesn't make an adaptation. In fact, failure to think about the consequences of a behavior can make it ineffective even though it may appear to be reasonable or even essential.