Sockeye salmon Pacific salmon, feed extensively on zooplankton during both freshwater and saltwater life stages. They also tend to feed on small aquatic organisms such as shrimp. Insects are part of their diets at the juvenile stage. Sockeye salmon exhibit many different life histories with the majority being anadromous where the juvenile salmon migrate from freshwater lakes and streams to the ocean before returning as adults to their natal freshwater to spawn. Similar to most Pacific salmon, sockeye salmon are semelparous, meaning they die after spawning once. Some sockeye, called kokanee, do not migrate to the ocean and live their entire lives
The purpose of a system is what it does be balanced by a more straightforwardly descriptive view. The term is used in many fields including biology and management. The purpose of a system is what it does The purpose of a system is what it does (POSIWID) is a systems thinking heuristic coined by Stafford Beer. Stafford Beer coined the term POSIWID and used it many times in public addresses. In his address to the University of Valladolid, Spain, in October 2001, he said "According to the cybernetician, the purpose of a system is what it does. This is a basic dictum. It stands for bald fact, which makes