Marine biologists study salt water organisms and limnologists study fresh water organisms. Marine biologists are sometimes called oceanographers, but oceanography usually refers to the study of the physical characteristics of oceans and the ocean floor. Biochemists study the chemical composition of living things. They try to understand the complex chemical combinations and reactions involved in metabolism, reproduction, growth, and heredity. Much of the work in biotechnology is done by biochemists and molecular biologists because this technology involves understanding the complex chemistry of life.
Botanists study plants and their environment.
Microbiologists investigate the growth and characteristics of microscopic organisms such as bacteria, algae, or fungi. Medical microbiologists study the relationship between organisms and disease or the effect of antibiotics on microorganisms. Many microbiologists are using biotechnology to advance knowledge of cell reproduction and human disease. Physiologists study life functions of plants and animals, both in the whole organism and at the cellular or molecular level, under normal and abnormal conditions. Physiologists may specialize in functions such as growth, reproduction, photosynthesis, respiration, or movement, or in the physiology of a certain area or system of the organism.