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

animal cell are presented in detail in this chapter along with the ways that genetic material divide. Both mitosis and meiosis, important in cellular and animal reproduction, are covered as part of this chapter.

Chapter five describes the inner workings of cellular metabolism. Animal cell metabolism involves primarily cellular respiration and the use of oxygen to break down nutrients for use as fuel or energy, usually resulting in the making of ATP, the universal energy currency of the cell. There are processes in place for anaerobic respiration and fermentation, which will be covered in this chapter. Plants use their cellular machinery to participate in photosynthesis, which yields oxygen and utilizes carbon dioxide. This process is also discussed as part of this chapter.

Genetics is the topic of discussion in chapter six in the course. It is the study of how traits are passed from one generation to the next, which involves the building blocks of genetics, DNA and RNA. These are divided into chromosomes and genes that together write the code that determines the offspring’s genotype (or genetic code) and phenotype (or physical appearance). Genes are tightly regulated so that some genes are expressed, while others are suppressed. This process of gene regulation is also covered in this chapter.

The focus of chapter seven in the course is the evolutionary process, whereby individual species and populations gradually change over time because of the natural selection of the species that have inherited advantages over other species. Much of this involves Darwinian evolutionary principles, which is covered in this chapter. The history of evolution on earth and the origin of species has been largely uncovered and these are important topics of discussion in this chapter.

The eighth chapter in the course covers the main divisions in nature and living things, outlining the six major kingdoms and their subdivisions. The way that biological species are defined is discussed in this chapter. The major features of each kingdom and how kingdoms and their subdivisions are determined are important topics of this chapter. Because archaea and Protista haven’t yet been covered, they are also discussed in separate sections.

Chapter nine in the course involves an extensive discussion of the cellular structures, basic anatomy, and reproductive functions of plants. Plants use much different nutrients when compared to animals and use these nutrients to participate in photosynthesis and in making nutritional substances used by many animal species. Plants are the subject of a great deal of discussion when it comes to biotechnology and genetic modification. This hot topic is covered in this chapter.

Chapter ten in the course discusses fungi, their anatomy and physiology. Fungi are a broad category of organisms, ranging from microscopic organisms to the commonlyknown fungi, such as mushrooms. What they have in common and how they differ from one another are covered in this chapter. Fungi have their own unique way of reproducing themselves, which will be explained as part of this chapter.

The focus of chapter eleven is the various systems that make up complex animals. All animals must have some way of obtaining nutrients through digestive systems, must circulate nutrients, and need to use respiration to have oxygen for energy. These will be different, depending on the animal species. Animal cells will have nervous systems of some sort and need strong immune systems to defend against pathogens. These systems as well as the endocrine systems and hormones in animal systems are discussed in this chapter.

Ecology is the subject of chapter twelve in the course. This is the study of ecosystems in the world as well as the biosphere, which are the regions of the earth inhabited by living organisms. The ecology of populations is covered in this chapter as well as the important and timely topic of global ecological changes that have happened, are happening, and will happen to the earth as a planet.