What is Free Evolution?
Free evolution is the concept that the natural processes of organisms can lead them to evolve over time. This includes the emergence and development of new species.
This has been demonstrated by numerous examples, including stickleback fish varieties that can thrive in saltwater or fresh water and walking stick insect species that prefer specific host plants. These typically reversible traits cannot explain fundamental changes to basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the development of all the living creatures that live on our planet for many centuries. The best-established explanation is that of Charles Darwin's natural selection, a process that occurs when individuals that are better adapted survive and reproduce more successfully than those who are less well adapted. Over time, a population of well-adapted individuals expands and eventually creates a new species.
Natural selection is a cyclical process that is characterized by the interaction of three factors including inheritance, variation, and reproduction. Variation is caused by mutations and sexual reproduction both of which increase the genetic diversity of the species. Inheritance is the term used to describe the transmission of a person’s genetic traits, which include both dominant and recessive genes, to their offspring. Reproduction is the process of producing fertile, viable offspring which includes both sexual and asexual methods.
Natural selection only occurs when all the factors are in equilibrium. For instance the case where an allele that is dominant at one gene causes an organism to survive and reproduce more frequently than the recessive allele, the dominant allele will become more prevalent within the population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will be eliminated. The process is self-reinforced, which means that an organism that has a beneficial trait is more likely to survive and reproduce than an individual with an unadaptive characteristic. The greater an organism's fitness as measured by its capacity to reproduce and survive, is the more offspring it can produce. People with desirable traits, like having a longer neck in giraffes and bright white patterns of color in male peacocks are more likely to survive and have offspring, so they will become the majority of the population over time.
Natural selection is an aspect of populations and not on individuals. This is a major distinction from the Lamarckian theory of evolution that states that animals acquire traits through the use or absence of use. For instance, if the Giraffe's neck grows longer due to stretching to reach prey and its offspring will inherit a larger neck. The difference in neck size between generations will continue to grow until the giraffe is unable to breed with other giraffes.
Evolution through Genetic Drift
In genetic drift, the alleles of a gene could reach different frequencies in a population due to random events. At some point, one will reach fixation (become so common that it can no longer be removed by natural selection), while the other alleles drop to lower frequencies. In the extreme, this leads to one allele dominance. The other alleles are basically eliminated and heterozygosity has been reduced to zero. In a small group, this could result in the complete elimination of recessive gene. This scenario is called the bottleneck effect and is typical of the evolutionary process that occurs when an enormous number of individuals move to form a group.
A phenotypic 'bottleneck' can also occur when the survivors of a catastrophe like an outbreak or a mass hunting event are concentrated in the same area. The survivors will be mostly homozygous for the dominant allele which means that they will all share the same phenotype, and consequently share the same fitness characteristics. This can be caused by earthquakes, war or even a plague. The genetically distinct population, if left vulnerable to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected value due to differences in fitness. They cite a famous instance of twins who are genetically identical and have the exact same phenotype but one is struck by lightening and dies while the other lives and reproduces.
This type of drift is very important in the evolution of an entire species. However, it's not the only way to progress. Natural selection is the most common alternative, where mutations and migrations maintain phenotypic diversity within a population.
Stephens argues that there is a major difference between treating the phenomenon of drift as a force or as an underlying cause, and considering other causes of evolution like selection, mutation, and migration as forces or causes. He argues that a causal-process explanation of drift lets us distinguish it from other forces and that this distinction is essential. He further argues that drift has an orientation, i.e., it tends towards eliminating heterozygosity. It also has a size which is determined based on population size.
Evolution through Lamarckism
Biology students in high school are often exposed to Jean-Baptiste lamarck's (1744-1829) work. His theory of evolution is often referred to as "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of characteristics that are a result of the natural activities of an organism, use and disuse. 에볼루션 게이밍 can be illustrated by an giraffe's neck stretching to reach higher levels of leaves in the trees. This could cause giraffes to give their longer necks to their offspring, who would then get taller.
Lamarck Lamarck, a French zoologist, presented a revolutionary concept in his opening lecture at the Museum of Natural History of Paris. He challenged conventional wisdom on organic transformation. In his opinion living things had evolved from inanimate matter through the gradual progression of events. Lamarck was not the first 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 broad and comprehensive analysis.
The dominant story is that Charles Darwin's theory of natural selection and Lamarckism were rivals during the 19th century. Darwinism eventually won and led to the creation of what biologists now call the Modern Synthesis. The theory argues that acquired traits are passed down from generation to generation and instead argues organisms evolve by the influence of environment factors, including Natural Selection.
Lamarck and his contemporaries endorsed the notion that acquired characters could be passed down to future generations. However, this concept was never a key element of any of their evolutionary theories. This is partly 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 large amount of evidence that supports the heritability of acquired characteristics. This is sometimes called "neo-Lamarckism" or more frequently, epigenetic inheritance. It is a form of evolution that is as valid as the more popular Neo-Darwinian model.
Evolution through Adaptation
One of the most popular misconceptions about evolution is being driven by a struggle for survival. This is a false assumption and ignores other forces driving evolution. The struggle for existence is more accurately described as a struggle to survive in a specific environment. This may include not only other organisms but also the physical environment.
To understand how evolution functions, it is helpful to consider what adaptation is. Adaptation refers to any particular feature that allows an organism to live and reproduce in its environment. It could be a physical feature, like fur or feathers. It could also be a trait of behavior that allows you to move towards shade during hot weather or escaping the cold at night.
The ability of an organism to extract energy from its environment and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism must have the right genes to produce offspring and be able find enough food and resources. Moreover, the organism must be capable of reproducing itself at a high rate within its niche.
These factors, along with mutation and gene flow can result in a change in the proportion of alleles (different forms of a gene) in the gene pool of a population. The change in frequency of alleles could lead to the development of new traits, and eventually, new species over time.
Many of the characteristics we admire in plants and animals are adaptations. For example lung or gills that extract oxygen from air, fur and feathers as insulation long legs to run away from predators and camouflage to conceal. To comprehend adaptation it is crucial to discern between physiological and behavioral traits.
Physiological adaptations, such as thick fur or gills, are physical traits, while behavioral adaptations, like the tendency to seek out companions or to move into the shade in hot weather, are not. It is important to note that lack of planning does not result in an adaptation. In fact, failure to think about the implications of a behavior can make it ineffective, despite the fact that it appears to be reasonable or even essential.