What is Free Evolution?
Free evolution is the concept that the natural processes that organisms go through can cause them to develop over time. This includes the development of new species as well as the change in appearance of existing ones.
This has been proven by numerous examples of stickleback fish species that can live in saltwater or fresh water and walking stick insect varieties that have a preference for specific host plants. These mostly reversible traits permutations are not able to explain fundamental changes to the basic body plan.
Evolution through Natural Selection
The development of the myriad living creatures on Earth is an enigma that has intrigued scientists for decades. Charles Darwin's natural selection theory is the most well-known explanation. This is because people who are more well-adapted survive and reproduce more than those who are less well-adapted. As time passes, the number of well-adapted individuals becomes larger and eventually forms a new species.
Natural selection is an ongoing process and involves the interaction of 3 factors including reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity of an animal species. Inheritance refers to the passing of a person's genetic traits to their offspring that includes recessive and dominant alleles. Reproduction is the process of generating viable, fertile offspring. This can be done by both asexual or sexual methods.
Natural selection only occurs when all these elements are in harmony. If, for instance an allele of a dominant gene makes an organism reproduce and survive more than the recessive gene then the dominant allele will become more common in a population. If the allele confers a negative advantage to survival or lowers the fertility of the population, it will go away. The process is self-reinforcing, meaning that a species that has a beneficial trait will survive and reproduce more than an individual with a maladaptive characteristic. The more offspring an organism produces, the greater its fitness that is determined by its capacity to reproduce and survive. People with desirable traits, like having a longer neck in giraffes, or bright white patterns of color in male peacocks are more likely to survive and have offspring, so they will eventually make up the majority of the population in the future.
Natural selection is only an element in the population and not on individuals. This is a crucial distinction from the Lamarckian evolution theory which holds that animals acquire traits due to use or lack of use. For instance, if the Giraffe's neck grows longer due to reaching out to catch prey its offspring will inherit a larger neck. The difference in neck length between generations will persist until the giraffe's neck gets too long that it can not breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles within a gene can reach different frequencies in a population by chance events. At some point, one will attain fixation (become so widespread that it is unable to be removed through natural selection), while other alleles will fall to lower frequencies. This could lead to dominance in extreme. The other alleles are eliminated, and heterozygosity falls to zero. In a small group this could result in the complete elimination of recessive allele. This scenario is called the bottleneck effect. It is typical of the evolution 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 confined to the same area. The survivors will share an allele that is dominant and will have the same phenotype. This could be caused by earthquakes, war, or even plagues. Whatever the reason the genetically distinct group that remains is susceptible to genetic drift.
Walsh Lewens and Ariew use a "purely outcome-oriented" definition of drift as any departure from the expected values of differences in fitness. They provide a well-known example of twins that are genetically identical and have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could play a very important role in the evolution of an organism. However, it's not the only way to develop. The primary alternative is a process called natural selection, in which the phenotypic variation of a population is maintained by mutation and migration.
Stephens claims that there is a huge difference between treating the phenomenon of drift as an actual cause or force, and treating other causes like selection mutation and migration as forces and causes. He argues that a causal-process model of drift allows us to distinguish it from other forces and this differentiation is crucial. He argues further that drift is both an orientation, i.e., it tends to eliminate heterozygosity. It also has a size which is determined based on population size.
Evolution by Lamarckism
Students of biology in high school are frequently exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution, also referred to as “Lamarckism” is based on the idea that simple organisms transform into more complex organisms through inheriting characteristics that are a product of the organism's use and misuse. Lamarckism is illustrated through an giraffe's neck stretching 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 then grow even taller.
에볼루션 바카라 무료 , a French Zoologist from France, presented an idea that was revolutionary in his opening lecture at the Museum of Natural History of Paris. He challenged the conventional wisdom on organic transformation. In his opinion living things had evolved from inanimate matter via the gradual progression of events. Lamarck was not the only one to suggest that this might be the case but his reputation is widely regarded as having given the subject his first comprehensive and comprehensive analysis.
The prevailing story is that Lamarckism grew into an opponent to Charles Darwin's theory of evolution through natural selection, and that the two theories fought out in the 19th century. Darwinism eventually won and led to the development of what biologists now refer to as the Modern Synthesis. This theory denies the possibility that acquired traits can be inherited and instead, it argues that organisms develop through the selective action of environmental factors, such as natural selection.
While Lamarck believed in the concept of inheritance through acquired characters, and his contemporaries also paid lip-service to this notion but it was not an integral part of any of their evolutionary theorizing. This is partly because it was never tested scientifically.
However, it has been more than 200 years since Lamarck was born and in the age of genomics there is a vast body of evidence supporting the possibility of inheritance of acquired traits. This is referred to as "neo Lamarckism", or more commonly epigenetic inheritance. This is a model that is as reliable as the popular neodarwinian model.
Evolution through the process of adaptation
One of the most commonly-held misconceptions about evolution is its being driven by a struggle to survive. In reality, this notion is a misrepresentation of natural selection and ignores the other forces that drive evolution. The fight for survival is better described as a fight to survive in a particular environment. This may be a challenge for not just other living things but also the physical surroundings themselves.
Understanding the concept of adaptation is crucial to understand evolution. The term "adaptation" refers to any characteristic that allows a living thing to live in its environment and reproduce. It can be a physical structure, like feathers or fur. It could also be a characteristic of behavior, like moving to the shade during hot weather or escaping the cold at night.
The capacity of a living thing to extract energy from its environment and interact with other organisms as well as their physical environments is essential to its survival. The organism must have the right genes for producing offspring and to be able to access sufficient food and resources. Moreover, the organism must be capable of reproducing in a way that is optimally within its niche.
These factors, in conjunction with mutations and gene flow, can lead to changes in the proportion of different alleles within the gene pool of a population. As time passes, this shift in allele frequency can result in the development of new traits, and eventually new species.
A lot of the traits we admire about animals and plants are adaptations, such as lung or gills for removing oxygen from the air, feathers or fur for insulation long legs to run away from predators and camouflage to hide. To comprehend adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physical characteristics like the thick fur and gills are physical characteristics. Behavioral adaptations are not, such as the tendency of animals to seek out companionship or to retreat into the shade in hot temperatures. It is important to keep in mind that lack of planning does not make an adaptation. In fact, failure to think about the implications of a choice can render it unadaptive, despite the fact that it may appear to be reasonable or even essential.