Rock of Gibraltar to describe an entity that is very safe or firm. The motto of the Royal Gibraltar Regiment and Gibraltar itself is "Nulli Expugnabilis Hosti" (Latin for "No Enemy Shall Expel Us"). Approximately 40% of Gibraltar's land area was declared a nature reserve in 1993. The flora and fauna of the Gibraltar Nature Reserve are of conservation interest and are protected by law. Within it is a range of animals and plants, but the highlights are the Barbary macaques (the famous "Rock apes"), the Barbary partridges, and flowers such as Gibraltar's own Chickweed, Thyme and the Gibraltar Candytuft. The Barbary macaques
On the Origin of Species to be separate species produced fertile hybrid offspring freely, and in other cases what were considered to be mere varieties of the same species could only be crossed with difficulty. Darwin concluded: "Finally, then, the facts briefly given in this chapter do not seem to me opposed to, but even rather to support the view, that there is no fundamental distinction between species and varieties." In the sixth edition Darwin inserted a new chapter VII (renumbering the subsequent chapters) to respond to criticisms of earlier editions, including the objection that many features of organisms were not adaptive and could not