What is Free Evolution?
Free evolution is the notion that natural processes can cause organisms to develop over time. This includes the development of new species as well as the change in appearance of existing species.
This has been proven by many examples, including stickleback fish varieties that can be found in fresh or saltwater and walking stick insect species that prefer particular host plants. These mostly reversible trait permutations can't, however, explain fundamental changes in body plans.
Evolution by Natural Selection
Scientists have been fascinated by the evolution of all the living organisms that inhabit our planet for ages. Charles Darwin's natural selection is the most well-known explanation. This process occurs when those who are better adapted survive and reproduce more than those who are less well-adapted. As time passes, a group of well-adapted individuals expands and eventually forms a whole new species.
Natural selection is a cyclical process that involves the interaction of three elements including inheritance, variation, and reproduction. Mutation and sexual reproduction increase the genetic diversity of the species. Inheritance refers to the transmission of a person's genetic traits, including both dominant and recessive genes, to their offspring. Reproduction is the process of producing viable, fertile offspring, which includes both asexual and sexual methods.
Natural selection only occurs when all the factors are in harmony. If, for instance, a dominant gene allele allows an organism to reproduce and live longer than the recessive gene allele then the dominant allele is more prevalent in a group. If the allele confers a negative survival advantage or reduces the fertility of the population, it will disappear. 에볼루션사이트 is self-reinforcing, which means that an organism with a beneficial characteristic can reproduce and survive longer than an individual with an unadaptive trait. The higher the level of fitness an organism has, measured by its ability reproduce and survive, is the greater number of offspring it will produce. People with good traits, such as a longer neck in giraffes, or bright white colors in male peacocks are more likely survive and have offspring, which means they will make up the majority of the population over time.
Natural selection only affects populations, not on individuals. This is a major distinction from the Lamarckian theory of evolution which holds that animals acquire traits through the use or absence of use. For instance, if a Giraffe's neck grows longer due to reaching out to catch prey and its offspring will inherit a longer neck. The differences in neck length between generations will persist until the giraffe's neck gets too long that it can not breed with other giraffes.
Evolution through Genetic Drift
Genetic drift occurs when alleles from one gene are distributed randomly within a population. At some point, only one of them will be fixed (become common enough to no more be eliminated through natural selection) and the other alleles diminish in frequency. In the extreme, this leads to dominance of a single allele. Other alleles have been essentially eliminated and heterozygosity has diminished to a minimum. In a small group it could lead to the complete elimination of recessive alleles. This is known as the bottleneck effect and is typical of an evolutionary process that occurs whenever an enormous number of individuals move to form a group.
A phenotypic bottleneck may occur when the survivors of a disaster such as an epidemic or a massive hunting event, are concentrated into a small area. The remaining individuals will be mostly homozygous for the dominant allele, meaning that they all share the same phenotype and will therefore have the same fitness traits. This situation could be caused by earthquakes, war, or even plagues. Whatever the reason the genetically distinct population that is left might be susceptible to genetic drift.
Walsh, Lewens and Ariew define drift as a deviation from expected values due to differences in fitness. They cite a famous example of twins that are genetically identical, have identical phenotypes and yet one is struck by lightning and dies, whereas the other lives and reproduces.
This kind of drift could be very important in the evolution of an entire species. But, it's not the only way to progress. The main alternative is a process called natural selection, in which the phenotypic diversity of an individual is maintained through mutation and migration.
Stephens argues that there is a significant difference between treating drift as a force or as a cause and treating other causes of evolution such as selection, mutation and migration as forces or causes. He claims that a causal-process explanation of drift lets us differentiate it from other forces and that this differentiation is crucial. He also argues that drift has a direction, i.e., it tends towards eliminating heterozygosity. It also has a size, which is determined by population size.
Evolution by Lamarckism
When high school students study biology they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is generally called "Lamarckism" and it states that simple organisms develop into more complex organisms by the inherited characteristics that result from the natural activities of an organism usage, use and disuse. Lamarckism is typically illustrated by the image of a giraffe that extends its neck to reach higher up in the trees. This would cause giraffes to give their longer necks to their offspring, which then get taller.
Lamarck Lamarck, a French Zoologist from France, presented a revolutionary concept in his 17 May 1802 opening lecture at the Museum of Natural History of Paris. He challenged the traditional thinking about organic transformation. According to Lamarck, living creatures evolved from inanimate materials by a series of gradual steps. Lamarck wasn't the first to make this claim, but he was widely thought of as the first to give the subject a comprehensive and general overview.
The most popular story is that Lamarckism became a rival to Charles Darwin's theory of evolutionary natural selection and that the two theories battled out in the 19th century. Darwinism eventually triumphed and led to the development of what biologists call the Modern Synthesis. This theory denies the possibility that acquired traits can be inherited and instead argues that organisms evolve through the selective action of environmental factors, including natural selection.
Lamarck and his contemporaries supported the idea that acquired characters could be passed on to future generations. However, this notion was never a major part of any of their theories on evolution. This is due in part to the fact that it was never tested scientifically.
It's been over 200 years since the birth of Lamarck and in the field of age genomics, there is a growing evidence-based body of evidence to support the heritability of acquired traits. This is also known as "neo Lamarckism", or more often epigenetic inheritance. It is a form of evolution that is as relevant as the more popular neo-Darwinian model.
Evolution by the process of adaptation
One of the most popular misconceptions about evolution is that it is driven by a sort of struggle for survival. In fact, 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 within a particular environment, which could involve not only other organisms, but also the physical environment itself.
Understanding adaptation is important to understand evolution. The term "adaptation" refers to any characteristic that allows a living thing to live in its environment and reproduce. It can be a physical structure, like feathers or fur. Or it can be a characteristic of behavior that allows you to move towards shade during hot weather, or coming out to avoid the cold at night.
The ability of an organism to draw energy from its environment and interact with other organisms, as well as their physical environments is essential to its survival. The organism should possess the right genes to produce offspring, and be able to find enough food and resources. The organism should also be able to reproduce at an amount that is appropriate for its specific niche.
These factors, together with gene flow and mutations can cause an alteration in the ratio of different alleles in a population’s gene pool. Over time, this change in allele frequencies can lead to the emergence of new traits and ultimately new species.
Many of the features we find appealing in animals and plants are adaptations. For instance, lungs or gills that extract oxygen from air feathers and fur for insulation long legs to run away from predators, and camouflage to hide. To comprehend adaptation, it is important to discern between physiological and behavioral characteristics.
Physical traits such as the thick fur and gills are physical traits. Behavior adaptations aren't an exception, for instance, the tendency of animals to seek companionship or move into the shade in hot weather. Additionally it is important to understand that a lack of thought does not mean that something is an adaptation. In fact, a failure to consider the consequences of a behavior can make it unadaptive, despite the fact that it may appear to be sensible or even necessary.