What is Free Evolution?
Free evolution is the idea that natural processes can cause organisms to evolve over time. This includes the evolution of new species and alteration of the appearance of existing species.
Many examples have been given of this, such as different kinds of stickleback fish that can live in either salt or fresh water, as well as walking stick insect varieties that favor specific host plants. These mostly reversible traits permutations are not able to explain fundamental changes to basic body plans.
Evolution through Natural Selection
Scientists have been fascinated by the evolution of all living creatures that inhabit our planet for ages. Charles Darwin's natural selectivity is the most well-known explanation. This happens when individuals who are better-adapted survive and reproduce more than those who are less well-adapted. Over time, a community of well-adapted individuals expands and eventually forms a whole new species.
Natural selection is a process that is cyclical and involves the interaction of three factors including reproduction, variation and inheritance. Sexual reproduction and mutation increase genetic diversity in an animal species. Inheritance is the passing of a person's genetic traits to his or her offspring that includes recessive and dominant alleles. Reproduction is the process of creating viable, fertile offspring. This can be done via sexual or asexual methods.
All of these elements have to be in equilibrium to allow natural selection to take place. If, for example the dominant gene allele causes an organism reproduce and last longer than the recessive allele, then the dominant allele will become more prevalent in a group. However, if the gene confers an unfavorable survival advantage or reduces fertility, it will disappear from the population. The process is self-reinforcing, which means that an organism with an adaptive characteristic will live and reproduce far more effectively than those with a maladaptive trait. The more offspring an organism produces the more fit it is, which is measured by its ability to reproduce itself and survive. Individuals with favorable characteristics, such as a long neck in giraffes, or bright white color patterns on male peacocks are more likely than others to live and reproduce which eventually leads to them becoming the majority.
Natural selection is only a force for populations, not on individuals. This is a significant distinction from the Lamarckian theory of evolution that states that animals acquire traits either through usage or inaction. For example, if a animal's neck is lengthened by stretching to reach prey, its offspring will inherit a larger neck. The differences in neck length between generations will persist until the giraffe's neck becomes too long to not breed with other giraffes.
Evolution by Genetic Drift
In the process of genetic drift, alleles at a gene may reach different frequencies in a population by chance events. Eventually, only sneak a peek at this web-site will be fixed (become common enough that it can no longer be eliminated by natural selection), and the rest of the alleles will decrease in frequency. In extreme cases this, it leads to one allele dominance. The other alleles are essentially eliminated, and heterozygosity decreases to zero. In a small number of people this could result in the total elimination of the recessive allele. This is known as the bottleneck effect. It is typical of an evolutionary process that occurs when a large number individuals migrate to form a group.
A phenotypic bottleneck could occur when survivors of a catastrophe, such as an epidemic or a massive hunting event, are condensed in a limited area. The survivors will carry an allele that is dominant and will have the same phenotype. This could be caused by earthquakes, war or even a plague. Whatever the reason the genetically distinct group that remains could be prone to genetic drift.
Walsh, Lewens, and Ariew utilize Lewens, Walsh, and Ariew use a "purely outcome-oriented" definition of drift as any departure from the expected values for different fitness levels. They give a famous example of twins that are genetically identical and have identical phenotypes, and yet one is struck by lightning and dies, while the other lives and reproduces.
This kind of drift could be very important in the evolution of the species. However, it's not the only method to develop. The main alternative is a process called natural selection, in which phenotypic variation in the population is maintained through mutation and migration.
Stephens argues that there is a big difference between treating drift as a force or as an underlying cause, and treating other causes of evolution like mutation, selection and migration as forces or causes. He argues that a causal-process explanation of drift lets us differentiate it from other forces and that this differentiation is crucial. He argues further that drift has both a direction, i.e., it tends to reduce heterozygosity. It also has a size which is determined based on the size of the population.
Evolution through Lamarckism
Students of biology in high school are frequently introduced to Jean-Baptiste Lemarck's (1744-1829) work. His theory of evolution is generally called "Lamarckism" and it states that simple organisms develop into more complex organisms by the inheritance of characteristics that result from the organism's natural actions use and misuse. Lamarckism is typically illustrated by a picture of a giraffe extending its neck to reach the higher branches in the trees. This could cause giraffes to pass on their longer necks to their offspring, who then become taller.
Lamarck, a French Zoologist, introduced an idea that was revolutionary in his 17 May 1802 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 a series of gradual steps. Lamarck was not the first to suggest that this could be the case, but he is widely seen as giving the subject his first comprehensive and comprehensive treatment.
The popular narrative is that Lamarckism grew into an opponent to Charles Darwin's theory of evolutionary natural selection and that the two theories battled each other in the 19th century. Darwinism eventually prevailed and led to the creation of what biologists now call the Modern Synthesis. This theory denies acquired characteristics can be passed down through generations and instead argues organisms evolve by the selective influence of environmental factors, including Natural Selection.
While Lamarck supported the notion of inheritance through acquired characters, and his contemporaries also paid lip-service to this notion however, it was not a major feature in any of their theories about evolution. This is due to the fact that it was never tested scientifically.
It's been over 200 year since Lamarck's birth and in the field of genomics there is a growing evidence-based body of evidence to support the heritability of acquired traits. It is sometimes called "neo-Lamarckism" or, more commonly, epigenetic inheritance. It is a form of evolution that is just as valid as the more well-known Neo-Darwinian model.
Evolution through adaptation
One of the most popular misconceptions about evolution is being driven by a struggle for survival. In reality, this notion is a misrepresentation of natural selection and ignores the 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 just other organisms, but also the physical environment itself.
To understand how evolution works it is beneficial to think about what adaptation is. Adaptation is any feature that allows a living organism to live in its environment and reproduce. It can be a physical structure such as feathers or fur. It could also be a characteristic of behavior such as moving to the shade during hot weather, or moving out to avoid the cold at night.
An organism's survival 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 create offspring and be able find enough food and resources. The organism should also be able reproduce at the rate that is suitable for its niche.
These factors, together with mutations and gene flow can result in a shift in the proportion of different alleles in a population’s gene pool. This change in allele frequency can result in the emergence of new traits and eventually, new species over time.
A lot of the traits we admire in animals and plants are adaptations, like lung or gills for removing oxygen from the air, fur or feathers for insulation, long legs for running away from predators and camouflage to hide. To comprehend adaptation it is essential to distinguish between behavioral and physiological characteristics.
Physiological adaptations, like thick fur or gills are physical traits, while behavioral adaptations, such as the tendency to search for companions or to move to the shade during hot weather, are not. It is important to note that insufficient planning does not make an adaptation. In fact, failing to consider the consequences of a choice can render it ineffective despite the fact that it may appear to be logical or even necessary.