Ecosystems and Organisms Quiz

An ecosystem consists of all the organisms and the physical environment with which they interact. Biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system.

Decomposers break down dead organic matter and release carbon back to the atmosphere. They facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes.

Resource inputs are generally controlled by external processes, but the availability of these resources within the ecosystem is controlled by internal factors. Therefore, internal factors not only control ecosystem processes but are also controlled by them.

External factors such as climate, parent material, and topography control the overall structure of an ecosystem. Internal factors, such as decomposition, root competition, shading, disturbance, succession, and the types of species present, are also influential.

By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present.