As used in this subchapter:
(1) “Descendants” means a person's children, grandchildren, and all others, however remotely related to such a person, who are in a direct line of descent from him or her. In other words, the term “descendants” refers to lineal descendants and excludes an intestate's ascendants or collateral relatives.
(2) The term “descendants”, wherever used in this subchapter, shall also include adopted children and their descendants of the intestate or of any other person in connection with whom the term “descendants” may be used.
(3) In determining which of an intestate's descendants shall constitute an inheriting class, the descendants of a living descendant shall be excluded from the class; and
(4) “Dying intestate” means dying without a valid last will and testament. A person so dying is referred to in this subchapter as an “intestate”, and it is recognized that a person may die wholly or partially intestate.