Compare And Contrast Directional Selection And Disruptive Selection

The third and final factor in bacterial resistance to antibiotics is bacterial genetic exchange. It is very common for bacteria to share genetic info between cells even if the bacteria are not the same species. When this happens, genes and DNA get mixed into different species allowing more mutations against the antibiotics.

Many pathogenic bacteria species are becoming resistant to antibiotic. Explain how such adaptations can develop through the process of natural selection.

Most of the ill-causing bacteria will be killed but the ones that don’t die, carry a gene or genes that allows them to withstand the antibiotic. These bacteria are better adapted to deal with the antibiotic. This adaptation will become stronger as it is passed. When these bacteria reproduce, they will pass the genes on to the next generation and the next generation bacteria better adapted against the antibiotic. The more they reproduce, the more antibiotic resistant bacteria will be in the individual eventually becoming totally resistant. This is an example of directional selection in the natural selection process. The bacteria with the resistant genes would become the favored extreme phenotype.

Directional selection and disruptive selection have quite a bit in common; however, they also have some contraries. Their biggest likeness is that they are both subcategories of natural selection. Natural selection is the process that results in adaptation of a population to the biotic and abiotic atmospheres. Directional selection takes place when an exaggerated phenotype is favored and the distribution curve alters in that direction. Such a shift can happen when a population is adjusting to a changing environment. Disruptive selection occurs when two or more extreme phenotypes are favored over any other ordinary phenotype. These two selections differ in that directional requires only one extreme phenotype whereas disruptive requires at least two. A prime example of a directional selection, is resistance to antibiotic treatment as well as insecticides. The extensive application of antibiotics and pesticides eventually develops populations of bacteria and insects that have grown resistant to the chemicals. When an antibiotic is employed, some bacteria may survive because they are genetically defiant to the treatment. These particular bacteria are likely to provide such genes for the next generation. As an outcome, the number of bacterial defiance continues to increase. Disruptive selection favors polymorphism, which is the happenings of different forms in a population of the exact same species. With thatstatement made, a classic example of disruptive selection would be that

Antibiotic resistance evolves in bacteria. Charles Darwin created the theory of evolution which focused on natural selection being the key factor of how things change. Natural selection is when organisms that are better suited to the environment are able to reproduce successfully. Evolution is descent with modification. Bacteria can become resistant to antibiotics by a mutation. The bacteria that did not die from the antibiotic inherited the gene from an ancestor that made it resistant. Since the other bacteria is dying faster than the resistant bacteria, the resistant bacteria are able to multiply

What are the real reasons behind the problem of bacterial resistance to antibiotics? There is not really any clear-cut answer to this question but there are some known factors that do contribute to the problem. Some of these include the overuse of antibiotics in livestock, international travel that can spread resistant bacteria, and the biggest single factor across the globe appears to be the very problem of misuse that Fleming warned of in 1945. Over prescription unnecessarily is still quite common today, and this is a primary contributor to the generation of bacterial resistance (Stivers, 2007).

Widespread use of antibiotics has been very controversial in the media as well in the general population. Due to these controversies, it is very misunderstood to how antibiotics work leading to many patients in the hospital setting wanting to take them when it is not necessary or refusing to take when it is necessary for their survival. Some of this controversy is due to antibiotic resistance, which has spread an alarming rate in the 21st century (Walsh, 2000). Antibiotic resistance is the result of very strong bacteria or microbes that are resistant to the antibiotic prescribed and those microbes accumulate overtime by their survival, reproduction and transfer, leading to increased levels of antibiotic resistance.

The overconsumption of antibiotics is a big contribution to drug resistance and is why users should know what happens with the repeated use of these drugs. Even though some bacterial mutation occurs naturally, human use of antibacterial is the cause of higher-levels of resistance (Alliance for the Prudent Use of Antibiotics 2014). Bacteria mutate either by genetic mutation or by receiving the defensive agent. During an infection bacteria multiply naturally within the body and when exposed to antibiotics, bacteria have an opportunity to adapt to the drug (Alliance for the Prudent Use of Antibiotics 2014). During this period of

The general populace of western civilization may believe that modern medicine is limitless and that numerous afflictions that are common can be easily resolved with the major strides medicine has taken in the past century. In the case of antibiotics, this couldn’t be farther from the truth and its use leaves a nasty prospect for the future. Antibiotics, the type of drug that is capable of killing harmful bacteria, is widely regarded as a simple gift from medical research and is expected to be prescribed for even the mildest of illnesses. However, the use of antibiotics has proved that it comes with a terrible byproduct: leftover bacteria that survives the drug and evolves strains that are resistant to the drugs the world currently

The video “Program Four: Creators of the Future” talks about microbes in general; especially how some of them are resistant to antibiotics in various circumstances. Microbes are all around the world, even inside us. Many microbes are beneficial to humans but some of them are not. They are mostly associated with illness and because of that, in 1928 Alexander Fleming invented penicillin, which is an antibiotic produced by mold. Penicillin was the first microbial product to kill human diseases. Some microbes are resistant to all antibiotics and cannot be treated. When penicillin functions correctly, it kills the bacteria by destroying their cell walls. Microbes reproduce by replicating themselves in two; when a mutation in the replication occurs, what happens is that the microbe with the mutation is going to be resistant to all antibiotics known for the moment. Nothing will stop microbes from mutating;

As mentioned above, bacteria can build resistance in those ways by changing their genetics a small amount. When they make more vitamins than necessary, it changes the genetics of the bacteria. Also, when they only allow molecules in a certain way, it is also changing their cell wall and genetics. When they let the antibiotic build up and then remove it altogether it is changing the genetics as well. They change their genetics and still carry out their functions in different ways.

Also known as superbugs, these bugs are resistant to our modern day antibiotics. People around the world are trying to figure out alternatives to this plague. These bugs have evolved over years and years becoming stronger and passing down genes from generation to generation, To slowly become the super bugs that they are known as today. Often these resistant genes are caused by overuse of antibiotics by humans and farm animals, but this is not always true. Recently the ARS (the American Recorder Society) found antibiotic resistance in prairie soils that had no human contact. Antibiotic resistance is commonly viewed as a result of antibiotic overuse in humans and animals, Recently found antibiotic-resistant

In the past tense 60 years, antibiotic drugs have been critical to the fight against infectious disease caused by bacteria and other microbe. Antimicrobial chemotherapy has been a lead cause for the dramatic rise of norm life expectancy in the Twentieth Century. 1 However, disease-causing bug that have become resistant to antibiotic drug therapy are an increasing public health trouble. “Wound contagion, tuberculosis, pneumonia, gonorrhea, childhood ear infections, and septicemia are just a few of the diseases that have become hard to treat with antibiotics.” 2 One part of the job is that bacteria and other germ that cause infections are remarkably resilient and have developed several ways to resist antibiotics and other antimicrobial drug. 3 Another part of the problem is due to increasing use, and abuse, of existing

1) Directional selection and disruptive selection both change up the allelic frequencies of a population. In directional selection one trait is selected over and over again, such that over time biggest part of the population all has that one trait. For example, over time all giraffes inherited tall necks, as tall necks helps the giraffes get to their food a lot easier. Disruptive selection is different from directional selection because instead of a population moving towards one trait, the population leans towards the extremes. For example if some plants need very little light and some need a whole lot of light, but cannot use an equal amount of light, then the plants may either select to be closer to the ground to avoid light or harder

Take for example MRSA (Methicillin-resistant Staphylococcus aureus), a S. aureus strain that was discovered in 1961 to be resistant to the antibiotic methicillin. Webmd indicates that MRSA has now grown its resistance from methicillin to “amoxicillin, penicillin, oxacillin and many other common antibiotics” (MRSA). This increase in resistance of a methicillin-resistant strain of S. aureus can be attributed to the increasing use and overuse of antibiotics, not only in the doctor’s office but also in agriculture. MRSA is only one of many antibiotic resistant strains of bacteria. New resistant strains are evolving rapidly. According to Dr. Ed Warren, “there are high levels of antibiotic resistance in bacteria causing common infections (e.g. urinary tract infections, pneumonia, bloodstream infections) in all regions of the world” (21).