What is Free Evolution?
Free evolution is the idea that the natural processes that organisms go through can cause them to develop over time. This includes the creation of new species as well as the change in appearance of existing species.
A variety of examples have been provided of this, including various varieties of fish called sticklebacks that can be found in salt or fresh water, as well as walking stick insect varieties that are attracted to specific host plants. These mostly reversible trait permutations, however, cannot explain fundamental changes in body plans.
Evolution by Natural Selection
The development of the myriad of living creatures on Earth is an enigma that has intrigued scientists for centuries. The most well-known explanation is Darwin's natural selection process, a process that occurs when better-adapted individuals survive and reproduce more successfully than those less well-adapted. Over time, the population of well-adapted individuals grows and eventually forms a new species.
Natural selection is an ongoing process that involves the interaction of three factors: variation, inheritance and reproduction. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity within the species. Inheritance is the transfer of a person's genetic traits to the offspring of that person which includes both recessive and dominant alleles. Reproduction is the process of producing viable, fertile offspring. This can be accomplished by both asexual or sexual methods.
All of these variables must be in harmony to allow natural selection to take place. If, for instance an allele of a dominant gene makes an organism reproduce and last longer than the recessive gene, then the dominant allele is more prevalent in a group. If the allele confers a negative advantage to survival or decreases the fertility of the population, it will disappear. The process is self-reinforcing, which means that the organism with an adaptive characteristic will live and reproduce far more effectively than one with a maladaptive characteristic. The higher the level of fitness an organism has as measured by its capacity to reproduce and survive, is the greater number of offspring it produces. Individuals with favorable characteristics, such as having a long neck in the giraffe, or bright white patterns on male peacocks are more likely to others to survive and reproduce and eventually lead to them becoming the majority.
Natural selection is only a factor in populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution, which claims that animals acquire characteristics by use or inactivity. For instance, if a animal's neck is lengthened by stretching to reach for prey and its offspring will inherit a larger neck. The differences in neck length between generations will continue until the giraffe's neck becomes so long that it can no longer breed with other giraffes.
Evolution by Genetic Drift
In genetic drift, the alleles of a gene could be at different frequencies in a group due to random events. In the end, only one will be fixed (become common enough that it can no longer be eliminated through natural selection) and the rest of the alleles will decrease in frequency. This can result in dominance in the extreme. The other alleles are basically eliminated and heterozygosity has been reduced to a minimum. In a small group this could lead to the complete elimination the recessive gene. This scenario is called the bottleneck effect. 에볼루션 바카라 무료 is typical of an evolutionary process that occurs when the number of individuals migrate to form a population.
A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an epidemic or mass hunt, are confined within a narrow area. The survivors will have an dominant allele, and will share the same phenotype. This could be caused by war, an earthquake or even a cholera outbreak. Regardless of the cause the genetically distinct group that remains could be susceptible to genetic drift.
Walsh, Lewens, and Ariew utilize a "purely outcome-oriented" definition of drift as any departure from the expected values of differences in fitness. They cite the famous example of twins that are genetically identical and share the same phenotype. However one is struck by lightning and dies, while the other continues to reproduce.
This type of drift is vital to the evolution of the species. This isn't the only method of evolution. Natural selection is the main alternative, where mutations and migration keep phenotypic diversity within the population.
Stephens asserts that there is a vast difference between treating drift like a force or cause, and considering other causes, such as migration and selection mutation as forces and causes. He claims that a causal-process explanation of drift lets us distinguish it from other forces and that this distinction is crucial. He also claims that drift has a direction: that is, it tends to eliminate heterozygosity, and that it also has a specific magnitude that is determined by the size of the population.
Evolution through Lamarckism
Biology students in high school are frequently introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution, also referred to as "Lamarckism, states that simple organisms transform into more complex organisms by taking on traits that result from the organism's use and misuse. Lamarckism can be illustrated by a giraffe extending its neck to reach higher leaves in the trees. This could cause the necks of giraffes that are longer to be passed to their offspring, who would grow taller.
Lamarck Lamarck, a French Zoologist, introduced an innovative idea in his opening lecture at the Museum of Natural History of Paris. He challenged traditional thinking about organic transformation. In his view living things evolved from inanimate matter through the gradual progression of events. Lamarck was not the first 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 thorough treatment.
The predominant story is that Charles Darwin's theory of evolution by natural selection and Lamarckism fought in the 19th century. Darwinism eventually triumphed and led to the creation of what biologists today call the Modern Synthesis. This theory denies the possibility that acquired traits can be inherited, and instead suggests that organisms evolve through the selective action of environmental factors, like natural selection.
Lamarck and his contemporaries supported the notion that acquired characters could be passed down to future generations. However, this concept was never a central part of any of their theories on evolution. This is due to the fact that it was never scientifically tested.
It has been more than 200 year since Lamarck's birth, and in the age genomics there is a growing evidence-based body of evidence to support the heritability acquired characteristics. This is referred to as "neo Lamarckism", or more often epigenetic inheritance. This is a variant that is as reliable as the popular neodarwinian model.
Evolution through Adaptation
One of the most common misconceptions about evolution is that it is being driven by a struggle for survival. This is a false assumption and overlooks other forces that drive evolution. The struggle for survival is more effectively described as a struggle to survive within a particular environment, which can be a struggle that involves not only other organisms, but as well the physical environment.
To understand how evolution works it is important to think about what adaptation is. The term "adaptation" refers to any characteristic that allows living organisms to live in its environment and reproduce. It could be a physiological feature, such as feathers or fur or a behavior, such as moving 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 surrounding environment and interact with other organisms and their physical environments. The organism must possess the right genes to produce offspring and to be able to access enough food and resources. Moreover, the organism must be capable of reproducing at an optimal rate within its environmental niche.
These factors, together with gene flow and mutations can cause changes in the proportion of different alleles within the population's gene pool. This change in allele frequency could lead to the development of new traits, and eventually new species over time.
A lot of the traits we admire in animals and plants are adaptations, for example, lungs or gills to extract oxygen from the air, fur or feathers for insulation, long legs for running away from predators, and camouflage to hide. To understand the concept of adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physical traits such as the thick fur and gills are physical characteristics. Behavioral adaptations are not like the tendency of animals to seek companionship or move into the shade in hot weather. In addition, it is important to understand that a lack of forethought does not make something an adaptation. In fact, a failure to think about the implications of a decision can render it unadaptive, despite the fact that it might appear reasonable or even essential.