Biologists study the origin, development, structure, and function of plant and animal life. The word biology comes from the Greek word bios, which means "mode of life." Like medicine and agriculture, biology covers a broad area within the life sciences. Biologists, also called biological scientists or life scientists, usually specialize in one area and are recognized and named by that specialty.
In many cases, biologists are recognized according to the kind of organism that they study. For example, biologists who study animals are often known as zoologists. Biologists who specialize in plants are called botanists. Those who work with microscopic forms of plant and animal life, such as bacteria, fungi, and viruses, are known as microbiologists.
Some biologists study aspects of life that are common to many living things. For example, anatomists study the structure of living things, ranging from single-celled plants and animals to human beings and redwood trees. Physiologists specialize in the study of the life functions of plants and animals. These functions include growth, respiration, and reproduction. Geneticists study heredity and how traits, or inherited characteristics, vary in all forms of life. They expand our knowledge about how traits originate and are passed on from one generation to another. Pathologists concentrate on the effects of diseases on the cells, tissues, and organs of plants and animals. Nutritionists study how food is used and changed into energy. They examine the ways in which living tissue is built and repaired by its use of vitamins, minerals, proteins, and other nutrients. Pharmacologists study the effects of drugs and other substances, such as poisons and dusts, on living organisms.