PREFACE The purpose of this course is to open up the world of biology to the inquiring student. Biology is simply the study of living things. In this course, you will learn about what constitutes a “living thing” versus nonliving organisms. Each of the main categories of living things will be covered, including the biology of viruses, bacteria, protists (including fungi), animals, and plants. Biology is also concerned with genetics, evolution, and ecology—each of which is important to the way that biological organisms appear to us in today’s time and in the future. Chapter one in the course will begin the discussion of living things by explaining what constitutes a living thing. There are certain characteristics that make humans, plants, and even viral particles called living things. The biochemistry of life is something that unifies life and involves molecules that are only seen, at least in concert, in things that are considered living organisms. Life exists, for the most part, in an aqueous environment and so the physiology of life in relation to water is covered in this chapter. Virus anatomy and function are the focus of chapter two in the course. Viruses are the most basic structures in life and, some would argue, they barely qualify as truly representing life. As you have seen in the first chapter, however, viruses are basic living things that have structure and that replicate. The way viruses multiply and cause disease in other living things is covered as part of this chapter. Chapter three covers the topic of bacteria. Bacteria are single-celled organisms that, compared to viruses, are remarkably complex. These are prokaryotes as opposed to the typical animal and plant eukaryotic cells with the ability to divide and grow independently of other organisms. There are many types of bacteria, some of which are motile. The physiology of bacteria, particularly the way they can become motile, is discussed in this chapter. Chapter four in the course explains animal cells and their biology. These are the cells and cell types people are more familiar with, with multiple organelles that unite to create basic animal cell physiology. The structure and function or “physiology” of the
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