I was selected to attend the NAIS Student Leadership and Diversity Conference. At the conference, I learned how to expound upon my beliefs and was inspired to make a difference in my community. I developed an independent study focused on diversifying the English and History curriculum, to give a voice to the unheard minorities at my school Natural selection is the differential survival and reproduction of individuals due to differences in blogger.com is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not Diversity is a peer-reviewed, open access journal on the science of biodiversity from molecules, genes, populations, and species, to ecosystems. Diversity is published monthly online by MDPI.. Open Access — free for readers, with article processing charges (APC) paid by authors or their institutions.; High Visibility: indexed within Scopus, SCIE (Web of Science), AGRICOLA, GEOBASE, CAPlus
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NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health. Institute of Medicine US Forum on Microbial Threats. Microbial Evolution and Co-Adaptation: A Tribute to the Life and Scientific Legacies of Joshua Lederberg: Workshop Summary. Washington DC : National Academies Press US ; Among his many contributions to efforts to recognize and address the threat of emerging infections, Lederberg co-chaired the committees that produced two landmark Institute of Medicine IOM reports, Emerging Infections: Microbial Threats to Health in the United States IOM, and Microbial Threats to Health IOM,which provided a crucial framework for understanding the drivers of infectious disease emergence Box WO-3 and Figure WO As the papers in this chapter demonstrate, this framework continues to guide research to elucidate the origins of emerging infectious threats, to inform the analysis of recent patterns of disease emergence, and to identify risks for future disease emergence events so as to enable early detection and response in the event of an outbreak, diversity essay evolution life selected, and perhaps even predict its occurrence.
Using hantavirus pulmonary syndrome and H5N1 influenza as examples, Morse demonstrates how zoonotic pathogens gain access to human populations. While many zoonotic pathogens periodically infect humans, few become adept at transmitting or propagating themselves, Morse observes. Human activity, however, is making this transition increasingly easy by creating efficient pathways for pathogen transmission around the globe.
Using a rigorous, formal methodology, Woolhouse and Gaunt produced and refined a catalog of the nearly 1, recognized human pathogen species. The authors note four attributes of these novel pathogens that they expect will describe most future emergent microbes: diversity essay evolution life selected preponderance of RNA viruses; pathogens with nonhuman animal reservoirs; pathogens with a broad host range; and pathogens with some perhaps initially limited potential for human-human transmission.
It depicts the approximately 1, pathogens capable of infecting humans, of which are capable of human-to-human transmission, and among which fewer than have the potential to cause epidemic or endemic disease; evolution—over a range of time scales—drives pathogens up the pyramid. The paper concludes with a discussion of the public health implications of the pyramid model, which suggests that ongoing global ecological change will continue to produce novel infectious diseases at or near the current rate of three per year.
In contrast to other contributors to this chapter, who focus on what, why, and where infectious diseases emerge, Jonathan Eisen, of the University of California, Davis, considers how new functions and processes evolve to generate novel pathogens, diversity essay evolution life selected. Knowledge of microbial genomes, and the functions they encode, is severely limited, Eisen observes.
Among 40 phyla of bacteria, for example, most of the available genomic sequences were from only three phyla; sequencing of Archaea and Eukaryote genomes has proceeded in a similarly sporadic manner.
These include constructing a model to predict relative risks for Nipah virus reemergence in Malaysia, where a outbreak devastated a thriving pig farming industry; identifying likely sources by which West Nile virus could spread to Hawaii, the Galapagos, and Barbados; and determining likely reservoirs of H5N1 influenza for specific geographic locations worldwide.
Daszak discusses the implications of hotspot location for global infectious disease surveillance, and describes how he and coworkers have used their knowledge of hotspots to target surveillance for Nipah diversity essay evolution life selected in India, diversity essay evolution life selected, and also to discover a virus with zoonotic potential in Bangladesh. We have all learned about the importance of infectious diseases throughout history, including the Plague of Justinian —the first known pandemic on record McNeill,and the Black Death in the fourteenth century.
Stanley Falkow, who is included in this volume, has extensively studied Yersinia pestisthe responsible organism, and given us important insights into its pathogenesis.
Another devastating disease that was once much feared is smallpox, which is said to have killed more people than all the wars in history. The eradication of smallpox was therefore a triumph of public health.
Ironically, smallpox has the unique property of being the only species to date that human beings have intentionally driven to extinction. While we have unintentionally driven so many species to extinction, it is nice to know we can actually intentionally do some good. Cholera was, of course, a very big concern in the nineteenth century and remains a concern today, especially in places like Bangladesh, as Gerald Keusch of Boston University and a member of the Diversity essay evolution life selected can affirm.
The influenza pandemic is one of our diversity essay evolution life selected of a nightmare emerging infectious disease event. It may very well have been the greatest diversity essay evolution life selected disaster in the early days of the twentieth century. But that pandemic is thought to have accounted for about 50 million or more deaths, depending on how you want to count it, diversity essay evolution life selected, and is obviously a matter of great concern.
Despite that, we have had years of complacency about infectious diseases, partly for reasons already discussed—the antibiotic era, immunizations, improved public health measures—all of which have led to the fact that we now live longer and tend to die later of chronic diseases. Unfortunately, this has not been true everywhere. It has not been true in many developing countries. Infectious diseases remain the major causes of morbidity and mortality in much of the world.
But in this paper, diversity essay evolution life selected, I would like to concentrate on emerging infections, the ones that are not previously recognized and that seem to appear suddenly and almost mysteriously—if you will, The Andromeda Strain Crichton, Figure WO-7 graphically shows a number of examples. Of course, there are also forgotten infections that reappear.
So when public health measures are relaxed or are abandoned because of lack of money or complacency—complacency being a very big problem—you then see forgotten infections reappearing. An example is diphtheria in the former Soviet Union and Eastern Europe in the early s when those countries no longer had the money to diversity essay evolution life selected their immunization programs, diversity essay evolution life selected.
It reminds us that many of these diseases may be forgotten, but they are not gone. HIV infection and AIDS, starting from obscurity, rose to become a leading cause of death in diversity essay evolution life selected United States by Figure You can find a molecular example of HIV in Zaire inbut that is almost a one-off, and then there were reports of a few cases in the s in Africa, if anyone had been paying attention.
Then suddenly, in the early s, it appeared in the United States and took off like the proverbial rocket to overtake all other causes of death in healthy young people. Of course, this is the same age group killed in the flu, but also the very people we generally expect to have the best survival rate.
They have survived childhood and we expect that they ought to be fine. As shown in Figurediversity essay evolution life selected, all the other causes of death were unchanged during that period, diversity essay evolution life selected.
Leading causes of diversity essay evolution life selected in young adults, United States, — Red line: Rise of HIV infection to become leading cause of death. SOURCE: CDC HIV was therefore quite a surprise. When you think about it, this does seem rather like The Andromeda Strain. We had thousands of years of experience with infections, some of them historically recorded in some detail.
Some of these are still unidentified, and we still argue about what they were. But a disease that actually kills by undermining the immune system directly was a novel mechanism of pathogenesis. How often does one find a new mechanism of pathogenesis in an infectious disease, considering the thousands of years of experience that we have had? I think it was quite remarkable. As a result, the trend reached a plateau and has recently been going down. But it also worries me that this fortunate situation may not last very long.
Inevitably, antiviral resistance has already been identified in some patients. Another concern is that some of the younger people have now become quite complacent about this disease, not knowing the devastation that many of us witnessed in the s, before it could be effectively treated. We are seeing young people now regarding this with less seriousness than they should. So there we are, facing complacency again. If there is a bottom line to the theme of the Forum on Microbial Threats, it is that we cannot afford to be complacent anymore, diversity essay evolution life selected.
What are emerging infections? I always like informally to define emerging infections as those that would knock a really important story off the front page of the newspaper, whether the runaway bride or the Texas polygamy case, at least for a day or two. However, I do have a more formal definition: those infections that are rapidly increasing in incidence or geographic range.
In some cases, these are novel, previously unrecognized diseases. But, as I am going to show you, many of them are not The Andromeda Strain. They do not come from space. Actually, in many cases, they have already existed in nature. Very often, anthropogenic causes—often as unintended consequences of things we do—are important in the emergence of these infections.
There are many examples. You can pick your favorite: Ebola in ; hantavirus pulmonary syndrome, which I will discuss briefly in a moment; Nipah, which Peter Daszak addressed at the workshop and his group has done some excellent work on this ; SARS ; and, of course, influenza, which still continues to surprise us.
But these are really a lot of little fires all over the world, most of which we did not spot in time before they became big brush fires or even wild-fires. Global examples of emerging and reemerging infectious diseases, some of which are discussed in the main text. SOURCE: more The basic lesson there is that many may be called, but few are chosen. In this two-step process, as you all know, the opportunities are increasing thanks to ecological changes and globalization, which gives the microbes great opportunities to travel along with us, and to travel very quickly.
Even medical technologies have played an inadvertent role in helping to disseminate emerging infections, diversity essay evolution life selected. What we now know is that many of these infections, exotic as they may seem, are often zoonotic. Some of them do not do very much, and may cause no infection at all; while others may cause a truly dramatic infection, like Ebola.
So that zoonotic pool, if I may use that term, is not fully chlorinated, and it is a rich source of potential emerging pathogens. There is so much biodiversity out there, including a tremendous biodiversity of microbes. Some of that biodiversity—we do not know how diversity essay evolution life selected, even now—is still untapped. Changes in the environment may increase the frequency of contact with a natural host carrying an infection, and therefore increase our chances of encountering microorganisms previously unknown to humans.
There are a number of examples associated with activities like agriculture, food-handling practices, and, for the vector biologists, of course, changes in water ecosystems. Table lists just some of these cases. The basic point is that there are a number of ecological changes, many of them anthropogenic, which provide new opportunities for pathogens to emerge and gain access to human populations.
Think of these as a sort of microbial explorers, discovering new niches—us—and exploring new territory.
It is important not to overlook the very important role of evolution as well. One role is obviously what evolution has already been doing for a long time, leading to the biodiversity of pathogens that we see existing in nature.
It is remarkable, diversity essay evolution life selected, when you think about how great that biodiversity is. But when I think about just the diversity essay evolution life selected, which are pretty well studied, that number could be very large indeed.
They can be found all over the world. Several of them are present at very high prevalence in the human population. That just gives you an idea of some of that great biodiversity. As it happens, these herpesviruses are all specialized for humans. There are, of course, herpes-viruses of other species. So a lot of coevolution between host and pathogen goes on as well. Of course, there is adaptation to new hosts and environments through natural selection, diversity essay evolution life selected.
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The extended essay (EE) is an integral part of the IB Diploma course. In order to write a good EE in ESS you need to first of all be interested in and passionate about the environment; and secondly be prepared to put in the hard work Jun 25, · Cultural diversity in the workplace; Are there similarities among different cultures? The link between culture and gender roles; After selecting culture essay questions for discussion, you can start working on your paper. Here are some secrets of the powerful paper on the topic: Conduct preliminary research on the selected issue Natural selection is the differential survival and reproduction of individuals due to differences in blogger.com is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not
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