In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. Starting with a single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos, but examples are known from around the world.
The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches generally have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usually resident and do not migrate. They have a worldwide native distribution except for Australia and the polar regions. The family Fringillidae contains more than two hundred species divided into fifty genera. It includes the canaries, siskins, redpolls, serins, grosbeaks and euphonias, as well as the morphologically divergent Hawaiian honeycreepers.
Hawaii is an island state of the United States, in the Pacific Ocean about 2,000 miles (3,200 km) southwest of the U.S. mainland. It is the only state not on the North American mainland, the only state that is an archipelago, and the only state in the tropics.
Midway Atoll is a 2.4 sq mi (6.2 km2) atoll in the North Pacific Ocean. Midway Atoll is an insular area of the United States and is an unorganized and unincorporated territory. The largest island is Sand Island, which has housing and an airstrip. Immediately to the east of Sand Island across the narrow Brooks Channel is Eastern Island, which is uninhabited and no longer has any facilities. Forming a rough, incomplete circle around the two main islands and creating Midway Lagoon is Spit Island, a narrow reef.
Maui is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the 17th-largest in the United States. Maui is one of Maui County's five islands, along with Molokaʻi, Lānaʻi, Kahoʻolawe, and Molokini.
The Hawaiian Islands are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaiʻi in the south to northernmost Kure Atoll. Formerly called the Sandwich Islands by Europeans, the present name for the archipelago is derived from the name of its largest island, Hawaiʻi.
The Hawaiian crow or ʻalalā is a species of bird in the crow family, Corvidae, that is currently extinct in the wild, though reintroduction programs are underway. It is about the size of the carrion crow at 48–50 cm (19–20 in) in length, but with more rounded wings and a much thicker bill. It has soft, brownish-black plumage and long, bristly throat feathers; the feet, legs, and bill are black. Today, the Hawaiian crow is considered the most endangered of the family Corvidae. They are recorded to have lived up to 18 years in the wild, and 28 years in captivity. Some Native Hawaiians consider the Hawaiian crow an ʻaumakua.
Mauna Kea is an inactive shield volcano on the island of Hawaiʻi. Its peak is 4,207.3 m (13,803 ft) above sea level, making it the highest point in Hawaii and the island with the second highest high point, behind New Guinea, the world's largest tropical island with multiple peaks that are higher. The peak is about 38 m (125 ft) higher than Mauna Loa, its more massive neighbor. Mauna Kea is unusually topographically prominent for its height: its prominence from sea level is fifteenth in the world among mountains, at 4,207.3 m (13,803 ft); its prominence from under the ocean is 9,330 m (30,610 ft), rivaled only by Mount Everest. This dry prominence is greater than Everest's height above sea level of 8,848.86 m (29,032 ft), and some authorities have labeled Mauna Kea the tallest mountain in the world, from its underwater base. Mauna Kea is ranked 8th by topographic isolation.
Macadamia is a genus of four species of trees in the flowering plant family Proteaceae. They are indigenous to Australia, native to northeastern New South Wales and central and southeastern Queensland specifically. Two species of the genus are commercially important for their fruit, the macadamia nut. Global production in 2015 was 160,000 tonnes. Other names include Queensland nut, bush nut, maroochi nut, bauple nut and, in the US, they are also known as Hawaii nut. It was an important source of bushfood for the Aboriginal peoples.
The spinner dolphin is a small dolphin found in off-shore tropical waters around the world. It is famous for its acrobatic displays in which it rotates around its longitudinal axis as it leaps through the air. It is a member of the family Delphinidae of toothed whales.
The Northwestern Hawaiian Islands or Leeward Hawaiian Islands are a series of islands and atolls in the Hawaiian island chain located northwest of the islands of Kauai and Niʻihau. Politically, they are all part of Honolulu County in the U.S. state of Hawaii, except Midway Atoll, which is a territory distinct from the State of Hawaii, and grouped as one of the United States Minor Outlying Islands. The United States Census Bureau defines this area, except Midway, as Census Tract 114.98 of Honolulu County. Its total land area is 3.1075 square miles (8.048 km2). All the islands except Nihoa are north of the Tropic of Cancer, making them the only islands in Hawaii that lie outside the tropics.
The Pearl and Hermes Atoll, also known as Pearl and Hermes Reef, is part of the Northwestern Hawaiian Islands, a group of small islands and atolls that form the farthest northwest portion of the Hawaiian island chain. The atoll consists of a variable number of flat and sandy islets, typically between five and seven. More were noted in historical sources but have since been lost to erosion and rising sea levels.
The Hawaiian monk seal is an endangered species of earless seal in the family Phocidae that is endemic to the Hawaiian Islands.
Monk seals are earless seals of the tribe Monachini. They are the only earless seals found in tropical climates. The two genera of monk seals, Monachus and Neomonachus, comprise three species: the Mediterranean monk seal, Monachus monachus; the Hawaiian monk seal, Neomonachus schauinslandi; and the Caribbean monk seal, Neomonachus tropicalis, which became extinct in the 20th century. The two surviving species are now rare and in imminent danger of extinction. All three monk seal species were classified in genus Monachus until 2014, when the Caribbean and Hawaiian species were placed into a new genus, Neomonachus.
The genus Pritchardia consists of between 24 and 40 species of fan palms found on tropical Pacific Ocean islands in Fiji, Samoa, Tonga, Tuamotus, and most diversely in Hawaii. The generic name honors William Thomas Pritchard (1829-1907), a British consul at Fiji.
The Papahānaumokuākea Marine National Monument (PMNM) is a World Heritage listed U.S. National Monument encompassing 583,000 square miles (1,510,000 km2) of ocean waters, including ten islands and atolls of the Northwestern Hawaiian Islands. It was created in June 2006 with 140,000 square miles (360,000 km2) and expanded in August 2016 by moving its border to the limit of the exclusive economic zone, making it one of the world's largest protected areas. It is internationally known for its cultural and natural values as follows:
The area has deep cosmological and traditional significance for living Native Hawaiian culture, as an ancestral environment, as an embodiment of the Hawaiian concept of kinship between people and the natural world, and as the place where it is believed that life originates and to where the spirits return after death. On two of the islands, Nihoa and Mokumanamana, there are archaeological remains relating to pre-European settlement and use. Much of the monument is made up of pelagic and deepwater habitats, with notable features such as seamounts and submerged banks, extensive coral reefs and lagoons.
The cardueline finches are a subfamily, Carduelinae, one of three subfamilies of the finch family Fringillidae, the others being the Fringillinae and the Euphoniinae. The Hawaiian honeycreepers are now included in this subfamily. Except for the Hawaiian honeycreepers which underwent adaptive radiation in Hawaii and have evolved a broad range of diets, cardueline finches are specialised seed eaters, and unlike most passerine birds, they feed their young mostly on seeds, which are regurgitated. Besides this, they differ from the other finches in some minor details of their skull. They are adept at opening seeds and clinging to stems, unlike other granivorous birds, such as sparrows and buntings, which feed mostly on fallen seeds. Some members of this subfamily are further specialised to feed on a particular type of seed, such as cones in the case of crossbills. Carduelines forage in flocks throughout the year, rather than keeping territories, and males defend their females rather than a territory or nest.
The Hawaiian hoary bat, also known as ʻōpeʻapeʻa, is a species of bat endemic to the islands of Hawaiʻi. The Hawaiian hoary bat occupies the major Hawaiian islands, making it the only extant and native terrestrial mammal in the islands. Some studies report that the mainland hoary bat lives in sympatry on the Hawaiian Islands alongside the Hawaiian hoary bat, although this is disputed. The Hawaiian hoary bat was officially named the state land mammal of Hawaiʻi in 2015. It is a federally listed endangered taxon of the United States.
The Makauwahi Cave is the largest limestone cave found in Hawaii. It lies on the south coast of the island of Kauaʻi, in the Māhāʻulepū Valley close to Māhāʻulepū Beach, and is important for its paleoecological and archaeological values. It is reached via a sinkhole and has been described as “…maybe the richest fossil site in the Hawaiian Islands, perhaps in the entire Pacific Island region”.
