Ecology is defined as the study of the relationship between organisms and their environment. The biological spectrum shows the hierarchy of biological systems from genes to ecosystems. An ecosystem is a biological community that interacts with its non-living environment, resulting in clearly defined trophic structures and material cycles. For example, a pond ecosystem includes abiotic factors like water and nutrients that support producer organisms like algae and plants. These are then consumed by primary and secondary consumer organisms like zooplankton and fish. Saprotrophic bacteria and fungi break down dead organic matter.