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.
Zoologists study animals their origin, behavior, diseases, and life processes.
Some experiment with live animals in controlled or natural surroundings while others dissect dead animals to study their structure. Ecologists study the relationship among organisms and between organisms and their environments and the effects of influences such as population size, pollutants, rainfall, temperature, and altitude. Agricultural scientists, who may also be classified as biological scientists, are included in a separate statement elsewhere in the Handbook. Biological scientists who do biomedical research are usually called medical scientistsMedical scientists working on basic research into normal biological systems often do so in order to understand the causes of and to discover treatment for disease and other health problems. Medical scientists may try to identify the kinds of changes in a cell, chromosome, or even gene that signal the development of medical problems, such as different types of cancer.