Terrestrial in the ecological sciences means of or on the ground. It may be of the habitat of plants that are on land or on the ground. All the terrestrial elements contradict water world. In a very general sense, the things that relate to the land are known as terrestrial. They belong to Earth. In terms of Biology, a terrestrial animal is one that lives only on the ground or land. Anything that is terrestrial is inhabitant of earth. It has been derived from Latin word terrestris from terra that means Earth.