What is Free Evolution?
Free evolution is the idea that the natural processes of organisms can cause them to develop over time. This includes the evolution of new species and change in appearance of existing species.
Numerous examples have been offered of this, including various kinds of stickleback fish that can live in fresh or salt water and walking stick insect varieties that favor particular host plants. These reversible traits cannot explain fundamental changes to basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the development of all living creatures that inhabit our planet for many centuries. The best-established explanation is that of Charles Darwin's natural selection process, which occurs when individuals that are better adapted survive and reproduce more successfully than those that are less well-adapted. Over time, the population of individuals who are well-adapted grows and eventually forms an entirely new species.
Natural selection is an ongoing process and involves the interaction of 3 factors that are: reproduction, variation and inheritance. Sexual reproduction and mutation increase the genetic diversity of the species. Inheritance is the passing of a person's genetic traits to their offspring which includes both recessive and dominant alleles. Reproduction is the process of generating fertile, viable offspring. This can be achieved by both asexual or sexual methods.
Natural selection can only occur when all the factors are in equilibrium. For instance when an allele that is dominant at the gene allows an organism to live and reproduce more frequently than the recessive allele the dominant allele will be more prominent in the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. This process is self-reinforcing which means that an organism with an adaptive characteristic will live and reproduce more quickly than those with a maladaptive feature. 에볼루션 슬롯게임 , measured by its ability reproduce and survive, is the greater number of offspring it will produce. People with desirable traits, like having a longer neck in giraffes, or bright white colors in male peacocks are more likely to survive and have offspring, and thus will eventually make up the majority of the population in the future.
Natural selection is only an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution, which argues that animals acquire traits by use or inactivity. If a giraffe stretches its neck in order to catch prey, and the neck becomes longer, then its offspring will inherit this characteristic. The length difference between generations will persist until the neck of the giraffe becomes too long to not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles of a gene are randomly distributed in a population. In the end, only one will be fixed (become common enough that it can no longer be eliminated by natural selection), and the other alleles will drop in frequency. In the extreme this, it leads to one allele dominance. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small population it could result in the complete elimination of recessive gene. Such a scenario would be called a bottleneck effect, and it is typical of the kind of evolutionary process that occurs when a large amount of individuals migrate to form a new population.
A phenotypic bottleneck could happen when the survivors of a disaster, such as an epidemic or a mass hunting event, are condensed in a limited area. The survivors will be largely homozygous for the dominant allele, which means they will all share the same phenotype and thus have the same fitness characteristics. This situation might be caused by war, earthquake, or even a plague. Regardless of the cause, the genetically distinct population that is left might be susceptible to genetic drift.
Walsh Lewens, Walsh and Ariew define drift as a departure from the expected value due to differences in fitness. They cite the famous example of twins that are genetically identical and have exactly the same phenotype, but one is struck by lightning and dies, while the other continues to reproduce.
This kind of drift can be crucial in the evolution of the species. It's not the only method for evolution. The primary alternative is a process known as natural selection, in which phenotypic variation in an individual is maintained through mutation and migration.
Stephens argues there is a vast distinction between treating drift as an actual cause or force, and treating other causes like migration and selection as causes and forces. He claims that a causal-process explanation of drift lets us distinguish it from other forces and this distinction is crucial. He further argues that drift has a direction: that is, it tends to eliminate heterozygosity. It also has a size, that is determined by the size of population.
Evolution by Lamarckism
Biology students in high school are often introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is often referred to as "Lamarckism" and it states that simple organisms grow into more complex organisms via the inheritance of traits which result from an organism's natural activities usage, use and disuse. Lamarckism is illustrated through an giraffe's neck stretching to reach higher leaves in the trees. This causes the necks of giraffes that are longer to be passed onto their offspring who would then grow even taller.
Lamarck was a French zoologist and, in his inaugural lecture for his course on invertebrate zoology held at the Museum of Natural History in Paris on the 17th May 1802, he presented an innovative concept that completely challenged previous thinking about organic transformation. According to Lamarck, living things evolved from inanimate matter by a series of gradual steps. Lamarck wasn't the only one to propose this, but he was widely thought of as the first to provide the subject a thorough and general overview.
The prevailing story is that Lamarckism was a rival to Charles Darwin's theory of evolutionary natural selection and that the two theories battled each other in the 19th century. Darwinism ultimately won and led to what biologists refer to as the Modern Synthesis. The theory denies that acquired characteristics can be passed down and instead, it claims that organisms evolve through the selective influence of environmental elements, like Natural Selection.
Lamarck and his contemporaries believed in the idea that acquired characters could be passed on to the next generation. However, this idea was never a key element of any of their theories on evolution. This is due to the fact that it was never scientifically validated.
It's 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 sometimes referred to as "neo-Lamarckism" or, more often, epigenetic inheritance. It is a form of evolution that is as valid as the more well-known neo-Darwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is that it is being driven by a struggle to survive. This is a false assumption and ignores other forces driving evolution. The fight for survival can be more precisely described as a fight to survive within a particular environment, which may include not just other organisms, but also the physical environment itself.
Understanding how adaptation works is essential to comprehend evolution. The term "adaptation" refers to any specific feature that allows an organism to survive and reproduce within its environment. It could be a physical structure, like fur or feathers. It could also be a characteristic of behavior such as moving towards shade during hot weather, or coming out to avoid the cold at night.
The ability of an organism to draw energy from its surroundings and interact with other organisms, as well as their physical environments is essential to its survival. The organism should possess the right genes for producing offspring, and be able to find sufficient food and resources. In addition, the organism should be capable of reproducing at a high rate within its environment.
These factors, in conjunction with gene flow and mutations can result in an alteration in the ratio of different alleles in the population's gene pool. As time passes, this shift in allele frequency can lead to the emergence of new traits and eventually new species.
Many of the features we appreciate in plants and animals are adaptations. For example, lungs or gills that draw oxygen from air feathers and fur as insulation long legs to run away from predators, and camouflage to hide. However, a complete understanding of adaptation requires paying attention to the distinction between physiological and behavioral traits.
Physiological traits like the thick fur and gills are physical characteristics. Behavioral adaptations are not an exception, for instance, the tendency of animals to seek out companionship or to retreat into the shade during hot weather. Additionally, it is important to understand that a lack of thought does not mean that something is an adaptation. A failure to consider the implications of a choice even if it seems to be rational, may make it inflexible.