Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through homeostasis (literally, “steady-state”), the ability of an organism to maintain constant internal conditions. These conditions may, however, change from one moment to the next. In order to function properly, cells need to have appropriate conditions such as proper temperature, pH, and appropriate concentration of diverse chemicals. Organs (groups of tissues working together) perform specific functions, such as carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body. Two internal functions regulated in an organism are nutrient transport and blood flow. Organisms have different mechanisms in order to maintain a beneficial internal environment.Įven the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses.
