Foundations In Microbiology 10Th Edition By Kathleen Park Talaro – Test Bank

Foundations In Microbiology 10Th Edition By Kathleen Park Talaro – Test Bank Sample Test CHAPTER 1 1. What does it mean to say microbes are ubiquitous? From the Latin ubique, meaning “everywhere”, it is a succinct way of saying that microbes exist everywhere throughout the natural world, even areas with extreme conditions. Other ways to express this idea are the terms universally widespread and constantly present. The only environments that are microbe- free have probably been artificially sterilized by humans. 2. What is meant by diversity? The term diversity is used to denote the immense variety in different types of organisms, with regard to such characteristics as appearance, life style, and distribution. Although about 1.2 million different species of organisms have been discovered and named, this is only a small fraction of the true diversity present over the entire planet and its millions of habitats. The case study emphasizes that we are still at the early stages in exploring the richness of life (especially of the microbial type) that is hidden and largely unknown because of small size and inaccessiblity. 3. Most important events and discoveries: Many hundreds of separate scientists and labs contributed to the rise of microbiology during its early history. Tools such as the microscope allowed direct observation of samples and their microbial contents. Microbes were subsequently seen as discrete entities that could be observed, described, and documented much like larger organisms. Development of laboratory techniques for culturing microbes using sterile techniques allowed macroscopic handling and control of microbes so they could be studied and understood in greater depth. Application of the scientific method and experiments to standardize the requirements for fact-based inquiries were very important. The abandonment of the spontaneous generation theory was especially significant because it departed from superstition and prejudice in favor of the scientific method. The institution of the germ theory of disease and the development of aseptic techniques were an essential contribution to medical aspects of microbiology. The knowledge that microbes cause food spoilage and disease led to early attempts to control microbes using heat and other methods. 4. Use of the scientific method: A hypothesis is a statement put forth by an investigator that purports to explain a phenomenon based upon a collection of observations, tests, and other objective criteria. It can be tested experimentally. A theory is a statement of confidence that scientifically-based observations provide a factual explanation for some natural phenomenon. It is supported by measurable data collected from numerous experiments used to test the hypothesis. Examples: For years, it was not really known what was the exact cause of tooth decay. Various hypotheses were proposed that acid, sugar, tooth hygiene, and other factors were involved. Finally, after having the correct conditions for experimentation (on animals that lacked normal resident microbes), it was determined that a combination of excess dietary sugar, lack of cleaning, and certain streptococci living in the mouth were the primary factors. Likewise, the germ theory of disease started out as a hypothesis, but after thorough verification, it became not only a theory, but is now considered a law because it has held true over several centuries of investigation. 5. Classification of microbes Evolution is a process by which organisms gradually change (evolve) over long periods of time through inheritance of modified characteristics from ancestors. It asserts that all organisms arise from preexisting forms and that this relatedness shows itself by similarities in structure, physiology, and genetics. Biologists and microbiologists use various means to show the pattern of evolution, including trees, taxonomy, classification, and nomenclature. Taxonomy is a hierarchical system, from general to specific, for assembling organisms into a scheme that emphasizes their origins and relatedness. Classification is the process of collecting organisms into distinct taxonomic groups according to defined characteristics. Nomenclature is the naming of these categories in collaboration with their level of classification. Most classification schemes are based on evolutionary relatedness, with organisms that are more closely related placed in the same taxonomic groups. The correct order of taxa, from broadest and most inclusive to most specific, is: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species. The five Kingdom system groups the archaea with the bacteria in the prokaryotic category. In comparison the domain system emphasizes the evolutionary separation of the Archaea from the Bacteria and their early relatedness with the Eukarya. The binomial system of nomenclature assigns a genus and species (scientific) name to each organism; the first letter of the genus is capitalized, the species is lowercase, and the two names are underlined or italicized. This system standardizes naming and ensures consistency and universality. Names may also provide an indication of noteworthy characteristics of the organisms or its discoverer.