what ecologist study
Ecologists study these relationships among organisms and habitats of many different sizes, ranging from the study of microscopic bacteria growing in a fish tank, to the complex interactions between the thousands of plant, animal, and other communities found in a desert. Ecologists also study many kinds of environments.
Ecology (from Greek: οἶκος, house, or environment; -λογία, study of)[A] is the scientific analysis and study of interactions among organisms and their environment. It is an interdisciplinary field that includes biology, geography, and Earth science.