Foundations in Microbiology 9th edition

Book Preface

The Scope of Microbiology

As we observe the natural world, teeming with life, we cannot help but be struck by its beauty and complexity. But for every feature that is visible to the naked eye, there are millions of other features that are concealed beyond our sight because of their small size. This alternate microscopic universe is populated by a vast microbial menagerie that is equally beautiful and complex. To sum up the presence of microbes in one word, they are ubiquitous.* They are found in all natural habitats and most of those that have been created by humans. As scientists continue to explore remote and unusual environments, the one entity they always fi nd is microbes. They exist deep beneath the polar ice caps, in the ocean to a depth of 7 miles, in hot springs and thermal vents, in toxic waste dumps, and even in the clouds.

Microbiology is a specialized area of biology that deals with tiny life forms that are not readily observed without magnifi cation,
which is to say they are microscopic.* These microscopic organisms are collectively referred to as microorganisms, microbes,* or several other terms, depending upon the purpose. Some people call them “germs” or “bugs” in reference to their role in infection and disease, but those terms have other biological meanings and perhaps place undue emphasis on the disagreeable reputation of microorganisms.

The major groups of microorganisms included in this study are bacteria, viruses, fungi, protozoa, algae, and helminths
(parasitic worms). As we will see in subsequent chapters, each group exhibits a distinct collection of biological characteristics. The nature of microorganisms makes them both easy and diffi cult to study. Easy, because they reproduce so rapidly and can usually be grown in large numbers in the laboratory. Diffi cult, because we can’t observe or analyze them without special techniques, especially the use of microscopes (see chapter 3).

Microbiology is one of the largest and most complex of the biological sciences because it integrates subject matter from many diverse disciplines. Microbiologists study every aspect of microbes—their genetics, their physiology, characteristics that may be harmful or benefi cial, the ways they interact with the environment, the ways they interact with other organisms, and their uses in industry and agriculture. See table 1.1 for an overview of some fi elds and occupations that involve basic study or applications in microbiology. Each major discipline in microbiology contains numerous subdivisions or specialties that deal with a specifi c subject area or fi eld (table 1.1). In fact, many areas of this science have become so specialized that it is not uncommon for a microbiologist to spend an entire career concentrating on a single group or type of microbe, biochemical process, or disease.

* ubiquitous (yoo-bik9-wih-tis) L. ubique, everywhere and ous, having. Being, or seeming to be, everywhere at the same time.
* microscopic (my0-kroh-skaw9-pik) Gr. mikros, small, and scopein, to see.
* microbe (my9-krohb) Gr. mikros, small, and bios, life. Among the specialty professions of microbiology are:
• geomicrobiologists, who focus on the roles of microbes in the development of earth’s crust (table 1.1B);
• marine microbiologists, who study the oceans and its smallest inhabitants;
• medical technologists, who do the tests that help diagnose pathogenic microbes and their diseases;
• nurse epidemiologists, who analyze the occurrence of infectious diseases in hospitals; and
• astrobiologists, who study the possibilities of organisms in space (see Case Study, page 29).

Studies in microbiology have led to greater understanding of many general biological principles. For example, the study of microorganisms established universal concepts concerning the chemistry of life (see chapters 2 and 8), systems of inheritance (see chapter 9), and the global cycles of nutrients, minerals, and gases (see chapter 26).