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 is evident in numerous examples such as the stickleback fish species that can thrive in saltwater or fresh water and walking stick insect varieties that have a preference for particular host plants. These reversible traits, however, cannot be the reason for fundamental changes in body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all the living creatures that live on our planet for centuries. 에볼루션 슬롯 accepted explanation is Darwin's natural selection, a process that is triggered when more well-adapted individuals live longer and reproduce more effectively than those who are less well adapted. Over time, the population of individuals who are well-adapted grows and eventually forms a new species.
Natural selection is a process that is cyclical and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Variation is caused by mutations and sexual reproduction both of which enhance the genetic diversity within a species. Inheritance refers the transmission of genetic traits, including both dominant and recessive genes to their offspring. Reproduction is the generation of viable, fertile offspring, which includes both asexual and sexual methods.
All of these elements must be in balance to allow natural selection to take place. If, for example, a dominant gene allele causes an organism reproduce and live longer than the recessive gene allele then the dominant allele becomes more common in a population. If the allele confers a negative advantage to survival or reduces the fertility of the population, it will go away. The process is self-reinforcing, meaning that an organism that has a beneficial trait is more likely to survive and reproduce than an individual with an inadaptive characteristic. The more offspring an organism produces, the greater its fitness which is measured by its ability to reproduce itself and live. Individuals with favorable traits, like a long neck in Giraffes, or the bright white color patterns on male peacocks, are more likely than others to live and reproduce, which will eventually lead to them becoming the majority.
Natural selection only affects populations, not individual organisms. This is a significant distinction from the Lamarckian evolution theory that states that animals acquire traits either through the use or absence of use. For instance, if the Giraffe's neck grows longer due to stretching to reach for prey and its offspring will inherit a larger neck. The difference in neck length between generations will persist until the neck of the giraffe becomes too long to no longer breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from a gene are randomly distributed in a group. At some point, one will reach fixation (become so common that it can no longer be eliminated by natural selection) and the other alleles drop to lower frequencies. In extreme cases it can lead to one allele dominance. The other alleles are eliminated, and heterozygosity falls to zero. In a small population this could result in the complete elimination of recessive allele. This is known as a bottleneck effect and it is typical of evolutionary process when a large amount of individuals migrate to form a new population.
A phenotypic bottleneck can also occur when the survivors of a catastrophe such as an outbreak or mass hunting event are concentrated in an area of a limited size. The survivors will carry an dominant allele, and will have the same phenotype. This situation might be the result of a war, earthquake or even a disease. The genetically distinct population, if it is left, could be 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 the famous case of twins who are both genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, while the other continues to reproduce.
This type of drift is crucial in the evolution of the species. However, it is not the only method to develop. The primary alternative is a process called natural selection, where the phenotypic variation of the population is maintained through mutation and migration.
Stephens claims that there is a big difference between treating the phenomenon of drift as a force or an underlying cause, and considering other causes of evolution like selection, mutation and migration as causes or causes. He claims that a causal process account of drift allows us to distinguish it from other forces, and that this distinction is crucial. He also argues that drift has a direction: that is it tends to eliminate heterozygosity, and that it also has a magnitude, that is determined by the size of the population.
Evolution through Lamarckism
Biology students in high school are often introduced to Jean-Baptiste Lamarck's (1744-1829) work. His theory of evolution is commonly referred to as "Lamarckism" and it states that simple organisms develop into more complex organisms through the inherited characteristics which result from the organism's natural actions, use and disuse. Lamarckism is typically illustrated with the image of a giraffe stretching its neck longer to reach the higher branches in the trees. This would cause the longer necks of giraffes to be passed on to their offspring who would then grow even taller.
Lamarck was a French Zoologist. In 에볼루션 슬롯 to begin his course on invertebrate zoology at the Museum of Natural History in Paris on the 17th May 1802, he presented an original idea that fundamentally challenged previous thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate matter 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 general and comprehensive treatment.
The prevailing story is that Lamarckism grew into a rival to Charles Darwin's theory of evolution through natural selection, and both theories battled it out in the 19th century. Darwinism eventually prevailed which led to what biologists call the Modern Synthesis. This theory denies that acquired characteristics can be inherited and instead, it argues that organisms develop through the selective action of environmental factors, like natural selection.
Although Lamarck supported the notion of inheritance by acquired characters, and his contemporaries also paid lip-service to this notion but it was not a central element in any of their evolutionary theories. This is partly because it was never scientifically validated.
However, it has been more than 200 years since Lamarck was born and in the age of genomics, there is a large amount of evidence that supports the possibility of inheritance of acquired traits. This is sometimes referred to as "neo-Lamarckism" or more frequently epigenetic inheritance. It is a variant of evolution that is as valid as the more popular Neo-Darwinian theory.
Evolution through adaptation
One of the most widespread misconceptions about evolution is that it is driven by a sort of struggle for survival. This view is a misrepresentation of natural selection and ignores the other forces that are driving evolution. The fight for survival can be more accurately described as a struggle to survive in a certain environment. This can be a challenge for not just other living things but also the physical surroundings themselves.
To understand how evolution functions, it is helpful to think about what adaptation is. The term "adaptation" refers to any specific characteristic that allows an organism to live and reproduce in its environment. It could be a physical feature, like feathers or fur. Or it can be a trait of behavior that allows you to move towards shade during the heat, or moving out to avoid the cold at night.
The capacity of an organism to extract energy from its environment and interact with other organisms as well as their physical environment is essential to its survival. The organism must have the right genes to create offspring and to be able to access enough food and resources. The organism should also be able to reproduce at a rate that is optimal for its particular niche.
These factors, together with mutation and gene flow can result in an alteration in the percentage of alleles (different types of a gene) in the gene pool of a population. This change in allele frequency can lead to the emergence of new traits and eventually, new species as time passes.
Many of the characteristics we admire in animals and plants are adaptations, for example, the lungs or gills that extract oxygen from the air, feathers or fur to provide insulation, long legs for running away from predators, and camouflage for hiding. To comprehend adaptation it is essential to differentiate between physiological and behavioral characteristics.
Physical characteristics like thick fur and gills are physical traits. The behavioral adaptations aren't, such as the tendency of animals to seek out companionship or to retreat into the shade in hot temperatures. In addition, it is important to understand that a lack of thought does not mean that something is an adaptation. In fact, failing to think about the implications of a behavior can make it unadaptable, despite the fact that it may appear to be sensible or even necessary.