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 an incipient species" and that "species are only strongly marked and permanent varieties". He argues for the ubiquity of variation in nature. Historians have noted that naturalists had long been aware that the individuals of a species differed from one another, but had generally considered such variations to be limited and unimportant deviations from the archetype of each species, that archetype being a fixed ideal in the mind of God. Darwin and Wallace made variation among individuals of the same species central to understanding the natural world. In Chapter III, Darwin asks how varieties "which I have called incipient species"