5 Free Evolution Leçons From The Professionals
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 transformation of the appearance of existing species.
This is evident in many examples such as the stickleback fish species that can be found in saltwater or fresh water and walking stick insect types that have a preference for particular host plants. These mostly reversible trait permutations can't, however, explain fundamental changes in basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the evolution of all living creatures that inhabit our planet for centuries. Charles Darwin's natural selection theory is the best-established explanation. This is because individuals who are better-adapted are able to reproduce faster and longer than those who are less well-adapted. As time passes, a group of well adapted individuals grows and eventually forms a whole new species.
Natural selection is an ongoing process that is characterized by the interaction of three factors: variation, inheritance and reproduction. Sexual reproduction and mutation increase the genetic diversity of a species. Inheritance refers to the transmission of a person’s genetic traits, which include both dominant and recessive genes, to their offspring. Reproduction is the generation of fertile, viable offspring which includes both sexual and asexual methods.
Natural selection is only possible when all these elements are in harmony. If, for example, a dominant gene allele makes an organism reproduce and last longer than the recessive gene The dominant allele is more prevalent in a population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will disappear. This process is self-reinforcing which means that an organism that has a beneficial trait is more likely to survive and reproduce than one with a maladaptive trait. The higher the level of fitness an organism has which is measured by its ability to reproduce and survive, is the more offspring it can produce. People with desirable traits, such as a longer neck in giraffes or bright white colors in male peacocks, are more likely to survive and have offspring, so they will make up the majority of the population in the future.
Natural selection is a factor in populations and not on individuals. This is a major distinction from the Lamarckian evolution theory, which states that animals acquire traits either through usage or inaction. If a giraffe expands its neck to catch prey and the neck grows larger, then its children will inherit this characteristic. The difference in neck length between generations will persist until the giraffe's neck becomes so long that it can not breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, the alleles of a gene could reach different frequencies within a population through random events. Eventually, only one will be fixed (become common enough that it can no more be eliminated through natural selection), and the other alleles will decrease in frequency. In the extreme it can lead to one allele dominance. The other alleles are eliminated, and heterozygosity is reduced to zero. In a small group, this could lead to the total elimination of recessive allele. This is known as the bottleneck effect and is typical of the evolution process that occurs when a large number individuals migrate to form a population.
A phenotypic bottleneck could happen when the survivors of a catastrophe such as an epidemic or mass hunting event, are condensed within a narrow area. The remaining individuals will be mostly homozygous for the dominant allele which means they will all share the same phenotype and thus share the same fitness characteristics. This situation could be caused by earthquakes, war or even plagues. The genetically distinct population, if it remains susceptible to genetic drift.
Walsh Lewens, Lewens, and Ariew use Lewens, Walsh and Ariew employ a "purely outcome-oriented" definition of drift as any deviation from the expected values of different fitness levels. They provide the famous case of twins who are both genetically identical and share the same phenotype. However, one is struck by lightning and dies, whereas the other continues to reproduce.
This kind of drift could play a crucial role in the evolution of an organism. This isn't 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 claims that there is a significant distinction between treating drift as a force or cause, and treating other causes like migration and selection mutation as causes and forces. He argues that a causal mechanism account of drift permits us to differentiate it from other forces, and that this distinction is crucial. He further argues that drift has a direction: that is it tends to reduce heterozygosity, and that it also has a specific magnitude that is determined by population size.
Evolution through Lamarckism
Biology students in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is commonly referred to as "Lamarckism" and it states that simple organisms grow into more complex organisms through the inheritance of traits that are a result of the natural activities of an organism usage, use and disuse. 에볼루션 사이트 is illustrated through an giraffe's neck stretching to reach higher leaves in the trees. This process would result in giraffes passing on their longer necks to offspring, which then become taller.

Lamarck the French zoologist, presented an innovative idea in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the previous thinking on organic transformation. According Lamarck, living organisms evolved from inanimate material by a series of gradual steps. Lamarck was not the first to suggest that this could be the case, but he is widely seen as being the one who gave the subject its first general and comprehensive analysis.
The popular narrative is that Lamarckism was an opponent to Charles Darwin's theory of evolutionary natural selection, and that the two theories fought each other in the 19th century. Darwinism ultimately prevailed, leading to what biologists refer to as the Modern Synthesis. The theory denies that acquired characteristics are passed down from generation to generation and instead, it claims that organisms evolve through the selective influence of environmental factors, including Natural Selection.
Lamarck and his contemporaries endorsed the idea that acquired characters could be passed on to future generations. However, this concept was never a key element of any of their theories on evolution. This is partly due to the fact that it was never validated scientifically.
It has been more than 200 year since Lamarck's birth, and in the age genomics, there is an increasing body of evidence that supports the heritability acquired characteristics. This is often called "neo-Lamarckism" or more frequently epigenetic inheritance. It is a form of evolution that is just as relevant as the more popular Neo-Darwinian model.
Evolution by adaptation
One of the most common misconceptions about evolution is its being driven by a struggle to survive. This is a false assumption and overlooks other forces that drive evolution. The struggle for existence is better described as a struggle to survive in a specific environment. This can include not only other organisms but also the physical environment.
Understanding how adaptation works is essential to understand evolution. The term "adaptation" refers to any specific characteristic that allows an organism to survive and reproduce in its environment. It could be a physiological feature, such as feathers or fur or a behavior, such as moving into shade in hot weather or coming out at night to avoid cold.
The survival of an organism depends on its ability to draw energy from the environment and interact with other living organisms and their physical surroundings. The organism must possess the right genes to produce offspring and be able find sufficient food and resources. The organism must also be able to reproduce at a rate that is optimal for its particular niche.
These elements, in conjunction with mutation and gene flow result in changes in the ratio of alleles (different types of a gene) in a population's gene pool. As time passes, this shift in allele frequency can result in the emergence of new traits, and eventually new species.
A lot of the traits we admire in animals and plants are adaptations. For instance, lungs or gills that draw oxygen from air, fur and feathers as insulation, long legs to run away from predators, and camouflage to hide. However, a thorough understanding of adaptation requires attention to the distinction between the physiological and behavioral characteristics.
Physiological adaptations, such as the thick fur or gills are physical characteristics, whereas behavioral adaptations, like the tendency to seek out companions or to retreat to the shade during hot weather, aren't. It is important to remember that a the absence of planning doesn't result in an adaptation. In fact, failure to think about the implications of a decision can render it ineffective despite the fact that it might appear reasonable or even essential.