Lithosphere 50–140 km thick (but beneath the mid-ocean ridges is no thicker than the crust), while continental lithosphere has a range in thickness from about 40 km to perhaps 280 km; the upper ~30 to ~50 km of typical continental lithosphere is crust. The mantle part of the lithosphere consists largely of peridotite. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity. Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle (peridotite) and is denser than continental lithosphere, for which the mantle is associated with crust made of
Names for the human species "Gaian") is frequently used, as it were naming humanity by its planet of origin. Incidentally, this situation parallels the naming motive of ancient terms for humanity, including "human" ("homo", "humanus") itself, derived from a word for "earth" to contrast humans as earth-bound with celestial beings (i.e. deities) in mythology. Names for the human species The common name of the human species in English is historically "man" (from Germanic), often replaced by the Latinate "human" (since the 16th century). In addition to the generally accepted taxonomic name "Homo sapiens" (Latin: "sapient man", Linnaeus 1758), other Latin-based names for the human species