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 miles wide. His explanation was a combination of migration and descent with modification. He went on to say: "On this principle of inheritance with modification, we can understand how it is that sections of genera, whole genera, and even families are confined to the same areas, as is so commonly and notoriously the case." Darwin explained how a volcanic island formed a few hundred miles from a continent might be colonised by a few species from that continent. These species would become modified over time, but would still be related to species found on the continent, and Darwin observed that