The concept of a tree of life has been used in science, religion, philosophy, and mythology. A tree of life is a common motif in various world theologies, mythologies, and philosophies. A mystical concept alluding to the interconnection of all life on our planet; and a metaphor for common descent in the evolutionary sense. The term tree of life may also be used as a synonym for sacred tree.
The tree of knowledge, connects heaven to the underworld (and realms in between) and the tree of life, connecting all forms of creation, are both forms of the world tree or cosmic tree, seen in many cultures represented as one Gaian mind.