Natural selection is one of the central mechanisms of evolutionary change and is the process responsible for the evolution of adaptive traits. Credit for this astonishing breakthrough must be given to the man known as the father of evolution and heredity, Charles Darwin, who expounded his theory of evolution in 1859. Natural selection is one of the principles that govern heredity. The first broadly refers to the fact that evolution has occurred such that organisms living today are different from their ancestors. Natural selection is the evolutionary process that explains the correspondence, or fit, between the characteristics of organisms and the environments in which they live. This principle holds that if evolution were explained as a car, then the theory of natural selection would be the driving force. The theory states that it is nature that controls and selects organisms, which tend to have traits favorable to survival while eliminating inferior species. This research paper examines Darwin's four main ideas about evolution, its relationship to the current problem of bacterial resistance to antibiotics, and its description in terms of the 20th century "modern evolutionary synthesis." Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay Darwin's theory is significantly a very important milestone in the process of evolution and origin of species. The principle is considered the key to the formation of new and higher species from old and existing species. That is, nature selects superior traits, which are transmitted to offspring independently of each other. The main explanation behind this theory is that a higher allele tends to be dominant over the others, mixing genetic makeup and traits that influence a certain segregated trait during the growth and development of the organism. There are many “evolutionary forces.” Natural selection is specifically the design of species and traits that are better able to survive and reproduce. It is impossible to imagine evolution without natural selection. It was initially considered the primary mechanism of evolution and is still considered the dominant driving force of change in the modern evolutionary synthesis. Natural selection can be thought of as a process of molding or guiding evolution. It does this in several ways. Directional selection occurs when the environment causes an allele to lose its dominant position in a population. Disruptive selection selects the two extreme expressions of a trait. Stabilizing selection occurs when extremes are less adaptive and intermediate phenotypes perform better. There would be no theory of evolution without natural selection. It is a process of change necessary for synthesis. While some controversy surrounds evolution as it applies to human populations, Darwin's theory applies to all organic species. The basic principles of evolution are simple and seem obvious to the modern reader. However, before Darwin, no scientist had put all the pieces of the puzzle together. Population variation: In every species, there is variation. This variability occurs even between related individuals. Siblings vary in color, size, weight and other characteristics. Other characteristics rarely vary, such as the number of limbs or eyes. The observer must be carefulwhen making generalizations about a population. Some populations show more variation than others, especially in isolated geographic areas like Australia, Galapagos, Madagascar, etc. Organisms found in these areas may be related to those in other parts of the world. However, due to very specific conditions in their environment, these species evolve with very distinct characteristics. Inherited Traits: Each species has traits determined by inheritance. Inherited traits passed from parents to offspring determine the characteristics of the offspring. Inherited traits that improve chances of survival are more likely to be passed on to subsequent generations. Of course, some traits, like weight and muscle mass, can also be affected by environmental factors like food availability. But characteristics developed by environmental influences will not be passed on to future generations. Only traits passed down through genes will be inherited. For example, if an organism inherits the genes for a larger skeletal mass but lack of nutrition prevents the individual from growing to that size, and the individual survives and reproduces, the genes for a larger skeletal mass larger will be transmitted. Species produce more offspring each year than the environment can support. This high birth rate results in competition between members of the species for the limited natural resources available. The struggle for resources determines the mortality rate within a species. Only surviving individuals reproduce and pass on their genes to the next generation. Survival of the fittest: Some individuals survive the struggle for resources. These individuals reproduce by adding their genes to subsequent generations. The traits that helped these organisms survive will be passed on to their offspring. This process is known as “natural selection.” Environmental conditions result in the survival of individuals with specific traits that are passed on through heredity to the next generation. Today we call this process “survival of the fittest.” Darwin used this expression, but he attributed the source to a fellow biologist, Herbert Spencer. Bacteria grow and multiply quickly and can reach large numbers. When bacteria multiply, one cell divides into two cells. Every time the bacteria goes through this process, there is a chance (or risk, depending on the end result) that errors will occur; so-called mutations. These mutations are random and can be located anywhere in the DNA. Although some mutations are harmful to the bacteria, others can provide an advantage under the right circumstances. Here Darwin's theory of natural selection comes into play. If a mutation gives the bacteria an advantage in a particular environment, that bacteria will grow better than its neighbors and can increase in number – it is selected for this. Mutations are a way for bacteria to become resistant to antibiotics. Certain spontaneous mutations (or genes acquired from other bacteria by horizontal gene transfer) can make the bacteria resistant to an antibiotic. If we were to treat the bacterial population with this specific antibiotic, only resistant bacteria would be able to multiply; the antibiotic selects for them. These bacteria can now increase in number and the end result is a population of primarily resistant bacteria. The process of natural selection of resistant bacteria. Antibiotics kill sensitive bacteria, but any resistant bacteria will survive..