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 were descended from one species of rock pigeon. Darwin saw two distinct kinds of variation: (1) rare abrupt changes he called "sports" or "monstrosities" (example: Ancon sheep with short legs), and (2) ubiquitous small differences (example: slightly shorter or longer bill of pigeons). Both types of hereditary changes can be used by breeders. However, for Darwin the small changes were most important in evolution. In Chapter II, Darwin specifies that the distinction between species and varieties is arbitrary, with experts disagreeing and changing their decisions when new forms were found. He concludes that "a well-marked variety may be justly called