What is Free Evolution?
Free evolution is the concept that natural processes can cause organisms to develop over time. This includes the appearance and development of new species.
Many examples have been given of this, including different varieties of fish called sticklebacks that can be found in salt or fresh water, as well as walking stick insect varieties that are attracted to particular host plants. These mostly reversible traits permutations do not explain the fundamental changes in basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the development of all living creatures that live on our planet for ages. Charles Darwin's natural selection is the best-established explanation. This happens when those who are better adapted are able to reproduce faster and longer than those who are less well-adapted. Over time, a community of well-adapted individuals expands and eventually becomes a new species.
Natural selection is an ongoing process that involves the interaction of three factors: variation, inheritance and reproduction. Mutation and sexual reproduction increase the genetic diversity of the species. Inheritance refers to the passing of a person's genetic characteristics to their offspring which includes both recessive and dominant alleles. Reproduction is the generation of fertile, viable offspring, which includes both asexual and sexual methods.
All of these factors must be in balance for natural selection to occur. If, for example an allele of a dominant gene makes an organism reproduce and survive more than the recessive gene, then the dominant allele will become more common in a population. If the allele confers a negative survival advantage or decreases the fertility of the population, it will disappear. The process is self reinforcing meaning that the organism with an adaptive trait will live and reproduce more quickly than one with a maladaptive characteristic. The more fit an organism is as measured by its capacity to reproduce and endure, is the higher number of offspring it will produce. Individuals with favorable characteristics, like longer necks in giraffes and bright white color patterns in male peacocks are more likely to survive and produce offspring, which means they will make up the majority of the population in the future.
Natural selection is an aspect of populations and not on individuals. This is a significant distinction from the Lamarckian theory of evolution that states that animals acquire traits due to usage or inaction. For instance, if a animal's neck is lengthened by reaching out to catch prey its offspring will inherit a larger neck. The difference in neck size between generations will increase until the giraffe becomes unable to reproduce with other giraffes.
Evolution through Genetic Drift
In genetic drift, alleles within a gene can reach different frequencies in a population by chance events. At some point, only one of them will be fixed (become common enough that it can no longer be eliminated by natural selection) and the other alleles drop in frequency. In extreme cases, this leads to one allele dominance. The other alleles are essentially eliminated, and heterozygosity is reduced to zero. In a small group it could result in the complete elimination of recessive gene. This is known as a bottleneck effect and it is typical of the kind of evolutionary process when a lot of individuals migrate to form a new population.
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 have a dominant allele and thus will share the same phenotype. This can be caused by earthquakes, war, or even plagues. Whatever the reason the genetically distinct population that remains is prone to genetic drift.
Walsh Lewens, Walsh, and Ariew define drift as a departure from the expected value due to differences in fitness. They provide the famous case of twins that are genetically identical and share the same phenotype, but one is struck by lightning and dies, but the other lives to reproduce.
This kind of drift could be very important in the evolution of a species. However, it's not the only method to develop. The most common alternative is a process called natural selection, where phenotypic variation in the population is maintained through mutation and migration.
Stephens asserts that there is a vast distinction between treating drift as an actual cause or force, and treating other causes such as migration and selection mutation as causes and forces. He argues that a causal mechanism account of drift allows us to distinguish it from other forces, and that this distinction is vital. He further argues that drift is a directional force: that is it tends to eliminate heterozygosity. It also has a specific magnitude which is determined by the size of the population.
Evolution through Lamarckism
When students in high school study biology, they are often introduced to the work of Jean-Baptiste Lamarck (1744 - 1829). His theory of evolution is commonly referred to as "Lamarckism" and it states that simple organisms grow into more complex organisms by the inherited characteristics which result from the organism's natural actions use and misuse. Lamarckism can be demonstrated by a giraffe extending its neck to reach higher leaves in the trees. This could cause giraffes' longer necks to be passed onto their offspring who would grow taller.
Lamarck, a French zoologist, 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 evolved from inanimate matter via an escalating series of steps. 에볼루션사이트 was not the only one to suggest that this could be the case, but his reputation is widely regarded as having given the subject its first broad and comprehensive treatment.
The most popular story is that Charles Darwin's theory on natural selection and Lamarckism were rivals during the 19th century. Darwinism ultimately prevailed which led to what biologists refer to as the Modern Synthesis. This theory denies that traits acquired through evolution can be inherited, and instead, it argues that organisms develop by the symbiosis of environmental factors, like natural selection.
Although Lamarck supported the notion of inheritance through acquired characters and his contemporaries also offered a few words about this idea, it was never a central element in any of their evolutionary theories. This is partly because it was never scientifically validated.
It has been more than 200 year since Lamarck's birth and in the field of genomics, there is an increasing body of evidence that supports the heritability-acquired characteristics. It is sometimes referred to as "neo-Lamarckism" or, more commonly, epigenetic inheritance. It is a form of evolution that is just as relevant as the more popular neo-Darwinian model.
Evolution through adaptation
One of the most common misconceptions about evolution is that it is being driven by a fight for survival. This view is inaccurate and ignores other forces driving evolution. The struggle for survival is more accurately described as a struggle to survive within a particular environment, which could be a struggle that involves not only other organisms but as well the physical environment.
Understanding how adaptation works is essential to comprehend evolution. Adaptation is any feature that allows a living organism to live in its environment and reproduce. It could be a physical structure like feathers or fur. Or it can be a trait of behavior, like moving to the shade during the heat, or escaping the cold at night.
The capacity of an organism to extract energy from its surroundings and interact with other organisms, as well as their physical environment, is crucial to its survival. The organism must have the right genes to generate offspring, and must be able to find sufficient food and other resources. The organism must also be able to reproduce itself at the rate that is suitable for its specific niche.
These factors, in conjunction with gene flow and mutations can cause an alteration in the ratio of different alleles within the gene pool of a population. 무료에볼루션 in frequency of alleles could lead to the development of new traits and eventually new species in the course of time.
Many of the characteristics we admire in plants and animals are adaptations. For instance lung or gills that extract oxygen from air feathers and fur for insulation and long legs to get away from predators and camouflage for hiding. However, a proper understanding of adaptation requires paying attention to the distinction between behavioral and physiological characteristics.
Physiological adaptations, such as thick fur or gills, are physical traits, whereas behavioral adaptations, such as the desire to find companions or to move to shade in hot weather, are not. It is also important to keep in mind that insufficient planning does not cause an adaptation. A failure to consider the implications of a choice, even if it appears to be logical, can cause it to be unadaptive.