Named for a scientist who discovered it in 1961, what is the term for the number of times a normal cell population will divide before it stops?
Hayflick limit Hayflick limit The Hayflick limit or Hayflick phenomenon is the number of times a normal human cell population will divide before cell division stops. The concept of the Hayflick limit was advanced by American anatomist Leonard Hayflick in 1961, at the Wistar Institute in Philadelphia, Pennsylvania, US. Hayflick demonstrated that a normal human fetal cell population will divide between 40 and 60 times in cell culture before entering a senescence phase. This finding refuted the contention by Nobel laureate Alexis Carrel that normal cells are immortal. Each time a cell undergoes mitosis, the telomeres on the ends of each chromosome
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