Gilbert and Ellice Islands atolls and coral islands in the western Pacific Ocean that are recognised as part of the Micronesia subregion of Oceania. The Gilbert Islands are the main part of what is now Republic of Kiribati ("Kiribati" is the Gilbertese rendition of "Gilberts") The atolls and islands of the Gilbert Islands are arranged in an approximate north-to-south line. In a geographical sense, the equator serves as the dividing line between the northern Gilbert Islands and the southern Gilbert Islands. The Ellice Islands are south of the Gilbert Islands. The Ellice Islands comprises three reef islands and six true atolls spread out between
Endemism in the Hawaiian Islands was critical to the formulation of his theory of evolution is far exceeded in the more isolated Hawaiian Islands. The relatively short time that the existing main islands of the archipelago have been above the surface of the ocean (less than 10 million years) is only a fraction of time span over which biological colonization and evolution have occurred in the archipelago. High, volcanic islands have existed in the Pacific far longer, extending in a chain to the northwest; these once mountainous islands are now reduced to submerged banks and coral atolls. Midway Atoll, for example, formed as a volcanic