What is Free Evolution?
Free evolution is the notion that the natural processes of organisms can lead to their development over time. This includes the creation of new species and 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 prefer particular host plants. These are mostly reversible traits, however, cannot explain fundamental changes in basic body plans.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all living creatures that live on our planet for ages. Charles Darwin's natural selectivity is the best-established explanation. This is because people who are more well-adapted have more success in reproduction and survival than those who are less well-adapted. As time passes, the number of well-adapted individuals grows and eventually creates an entirely new species.
Natural selection is a process that is cyclical and involves the interaction of three factors that are: reproduction, variation and inheritance. Sexual reproduction and mutation increase the genetic diversity of a species. Inheritance is the term used to describe the transmission of genetic traits, which include recessive and dominant genes to their offspring. Reproduction is the process of producing viable, fertile offspring, which includes both sexual and asexual methods.
Natural selection is only possible when all the factors are in balance. If, for instance, a dominant gene allele makes an organism reproduce and last longer than the recessive allele then the dominant allele is more common in a population. If the allele confers a negative survival advantage or reduces the fertility of the population, it will go away. The process is self-reinforcing which means that an organism with an adaptive trait will survive and reproduce far more effectively than those with a maladaptive trait. The more offspring an organism can produce, the greater its fitness, which is measured by its capacity to reproduce and survive. Individuals with favorable traits, like a longer neck in giraffes or bright white color patterns in male peacocks, are more likely to survive and produce offspring, so they will become the majority of the population in the future.
Natural selection only affects populations, not on individual organisms. This is a significant distinction from the Lamarckian theory of evolution, which claims that animals acquire traits by use or inactivity. If a giraffe extends its neck to reach prey and its neck gets longer, then its children will inherit this characteristic. The differences in neck size between generations will continue to grow until the giraffe is unable to breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles of the same gene are randomly distributed within a population. At some point, only one of them will be fixed (become widespread enough to not longer be eliminated through natural selection) and the other alleles will decrease in frequency. This could lead to dominance in the extreme. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small population this could lead to the complete elimination the recessive gene. This scenario is known as a bottleneck effect and it is typical of evolutionary process that takes place when a lot of individuals migrate to form a new group.
A phenotypic 'bottleneck' can also occur when the survivors of a disaster such as an outbreak or mass hunt incident are concentrated in a small area. The survivors are likely to be homozygous for the dominant allele meaning that they all have the same phenotype and therefore share the same fitness characteristics. This situation could be caused by earthquakes, war or even a plague. The genetically distinct population, if left, could be susceptible to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from expected values due to differences in fitness. They give the famous example of twins who are genetically identical and share the same phenotype. However, one is struck by lightning and dies, whereas the other continues to reproduce.
This type of drift is very important in the evolution of the species. It's not the only method of evolution. Natural selection is the main alternative, where mutations and migration keep the phenotypic diversity of the population.
Stephens argues there is a huge difference between treating drift like an actual cause or force, and treating other causes such as migration and selection mutation as causes and forces. He claims that a causal-process explanation of drift lets us distinguish it from other forces and this differentiation is crucial. He also argues that drift is both an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined by population size.
Evolution through Lamarckism
When high school students take biology classes, they are frequently introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution, commonly referred to as "Lamarckism is based on the idea that simple organisms evolve into more complex organisms taking on traits that are a product of the use and abuse of an organism. Lamarckism is illustrated through the giraffe's neck being extended to reach higher branches in the trees. This process would cause giraffes to give their longer necks to their offspring, who would then grow even taller.
Lamarck, a French Zoologist from France, presented an idea that was revolutionary in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged traditional thinking about organic transformation. In his view, living things had evolved from inanimate matter through an escalating series of steps. Lamarck wasn't the first to propose this but he was regarded as the first to provide the subject a thorough and general overview.
The dominant story is that Charles Darwin's theory of natural selection and Lamarckism fought during the 19th century. click through the next webpage prevailed, leading to the development of what biologists call the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead, it claims that organisms evolve through the selective action of environment factors, such as Natural Selection.
Lamarck and his contemporaries supported the idea that acquired characters could be passed on to future generations. However, this idea was never a major part of any of their evolutionary theories. This is largely due to the fact that it was never tested scientifically.
However, it has been more than 200 years since Lamarck was born and in the age genomics there is a huge amount of evidence to support the possibility of inheritance of acquired traits. This is often called "neo-Lamarckism" or, more commonly, epigenetic inheritance. It is a form of evolution that is as relevant as the more popular Neo-Darwinian theory.
Evolution through adaptation
One of the most widespread misconceptions about evolution is that it is a result of a kind of struggle to survive. This is a false assumption and overlooks other forces that drive evolution. The fight for survival is better described as a fight to survive in a certain environment. This can be a challenge for not just other living things as well as the physical environment.
To understand how 에볼루션 , it is helpful to understand what is adaptation. It refers to a specific feature that allows an organism to survive and reproduce in its environment. It could be a physical structure, like feathers or fur. It could also be a behavior trait, like moving towards shade during hot weather or escaping the cold at night.
The ability of an organism to draw energy from its surroundings and interact with other organisms and their physical environments is essential to its survival. The organism must possess the right genes to produce offspring, and it must be able to locate sufficient food and other resources. The organism must also be able reproduce itself at an amount that is appropriate for its particular niche.
These factors, together with gene flow and mutation, lead to an alteration in the percentage of alleles (different types of a gene) in the gene pool of a population. As time passes, this shift in allele frequency can result in the emergence of new traits and ultimately new species.
Many of the characteristics we admire in animals and plants are adaptations, like the lungs or gills that extract oxygen from the air, fur or feathers to provide insulation, long legs for running away from predators and camouflage for hiding. To understand the concept of adaptation it is essential to discern between physiological and behavioral characteristics.
Physiological adaptations like thick fur or gills, are physical traits, whereas behavioral adaptations, like the tendency to search for companions or to move to shade in hot weather, are not. It is important to note that the absence of planning doesn't cause an adaptation. In fact, failing to think about the implications of a decision can render it unadaptive despite the fact that it might appear reasonable or even essential.