The Urals divide into five sections. The northernmost Polar Urals extend some 240 m.... mount river

The northernmost Polar Urals extend some 240 miles from Mount Konstantinov Kamen in the northeast to the Khulga River in the southeast; most mountains rise to 3,3003,600 feet (1,0001,100 metres) above sea level, although the highest peak, Mount Payer, reaches 4,829 feet. Farther south come the Northern Urals, which stretch for more than 340 miles to the Usa River in the south; most mountains top 3,300 feet, and the highest peak, Mount Telpos-Iz, rises to 5,305 feet. The last portion, the Southern Urals, extends some 340 miles to the westward bend of the Ural River and consists of several parallel ridges rising to 3,900 feet and culminating in Mount Yamantau, 5,380 feet; the section terminates in the wide uplands (less than 2,000 feet) of the Mughalzhar Hills. mount river

Coraciiform birds tend to perch in trees and shrubs when at rest. Some favour exposed perches on which they are consp.... ground feed

Some species, such as the kingfishers, use little bipedal locomotion; others ( e.g., some hornbills) hop, walk, or scramble in the treetops, creep along branches (wood hoopoes), or walk or hop on the ground (hoopoe, other hornbills). Some families (Upupidae and Leptosomatidae) contain only one species; others are large and predictably diverse e.g., the hornbills (Bucerotidae), with 45 species, and the kingfishers (Alcedinidae), with about 90 species. Each family or group of families tends to have a characteristic pattern of feeding behaviour, and the foraging patterns fall into four categories, or feeding niches: (1) watchful waiting on a perch, (2) aerial i.e., spending much time on the wing, (3) searching on foot among branches of trees, and (4) walking on the ground. When they see their prey on a leaf, a branch, the ground, or even in water, they fly out with swift, direct flight, seize the prey with the bill, and return to the perch. Rollers spend more time perched, but ! they too are graceful in flight and capture much of their food by hawking or by darting down to the ground. The wood hoopoes have weak flight, and they do not fly much; they fly chiefly from one tree or clump of trees to the next, climbing about the trunks and branches of trees and lianas in acrobatic poses as they seek insects in crevices and on the bark surface. Walking on the ground is the usual mode of feeding for the common hoopoe ( Upupa ), the ground rollers, and for a few hornbills. The ground rollers, most of which are birds of the deep forest, also feed on the ground on food similar to that of the hoopoe. ground feed

The Thames is some 205 miles (330 km) long, running 140 miles (226 km) from the s.... cubic feet

The average flow at the upper limit of the tideway, at Teddington, is 1,856 cubic feet (53 cubic metres) per second, rising to 4,640 cubic feet (130 cubic metres) per second after winter rain. In extreme floods (e.g., March 1947) the discharge at Teddington Weir may be as much as 20,900 cubic feet (590 cubic metres) per second. Reputedly, an average of 31,310 cubic feet (887 cubic metres) per second passed over it one day after heavy storms in 1894. cubic feet

Sirens usually burrow in mud in the bottom of marshes or streams or hide among water plants or stones, but s.... siren (

They mate in the water and lay eggs singly or in batches on the leaves of water plants. The greater siren ( Siren lacertina ) is 5090 cm (about 2035 inches) long and occurs in the Atlantic coastal states of the United States from Delaware southward to Florida and westward to northern Mexico. The lesser siren ( Siren intermedia ) is about 1760 cm long and is found from South Carolina to Texas and in the Mississippi Valley northward to Illinois and Indiana. The dwarf siren ( Pseudobranchus striatus ), of which at least five races have been identified, is about 1221 cm long. siren (

The four Phocoena species are primarily fish eaters that usually swim in pairs or small groups along coastlines and oc.... porpois dall

The four Phocoena species are primarily fish eaters that usually swim in pairs or small groups along coastlines and occasionally in rivers. The Dall porpoise ( Phocoenoides dalli ) is the largest porpoise and the only member of its genus. The Dall porpoise is black with a large white patch on each side of the body. It is usually seen in groups of 2 to 20 along the northern rim of the Pacific Ocean, where they eat squid and fish. dalli truei ) is considered by some authorities to be a separate subspecies and is distinguished from the Dall porpoise by its absence of the striking white body patches. The finless porpoise ( Neophocaena phocaenoides ) is a small, slow-moving inhabitant of coastal waters and rivers along the Indian Ocean and western Pacific Ocean. The finless porpoise lives alone or in small groups and eats crustaceans, fish, and squid. porpois dall

The platypus is common in waterways of eastern Au.... system navig

The senses of sight, smell, and hearing are essentially shut down while the platypus is submerged to feed, but it possesses a unique electromechanical system of and touch receptors that allow it to navigate perfectly under water. Although it has on occasion been seen swimming in salt water, the platypus must feed in fresh water, where its electrical navigation system is operative. Studies have shown that they can maintain a constant body temperature even after extended periods in water with temperatures as low as 4 C (39 F), a fact that puts to rest the belief that monotremes cannot regulate their body temperature. system navig

Pelicans eat fish, which they catch by using the extensible thr.... pelican white

One species, the brown pelican ( P. occidentalis; see ), captures fish by a spectacular plunge from the air, but other species swim in formation, driving small schools of fish into shoal water where they are scooped up by the birds ( see ). Pelicans lay one to four bluish white eggs in a stick nest, and the young hatch in about a month. The best-known pelicans are the two species called Pelecanus erythrorhynchos of the New World, the North American white pelican, and P. Pelicans usually breed in colonies on islands; there may be many small colonies on a single island. The gregarious North American white pelican breeds on islands in lakes in north-central and western North America; all pairs in any colony at any given time are in the same stage of the reproductive cycle. pelican white

Nearly 3,000 years ago the kite was first popularized, if not invented, in , where materials ideal for k.... kite silk

Nearly 3,000 years ago the kite was first popularized, if not invented, in , where materials ideal for kite building were readily available: silk fabric for sail material, fine, high-tensile-strength silk for flying line, and resilient bamboo for a strong, lightweight framework. Although the rules of kite fighting varied from country to country, the basic combat was to maneuver the swift kite in such a way as to cut the opponent's flying line. kite silk

Hesperornis was clearly an actively swimming bird that probably chased and caught fish. Although .... hesperorni )

MLA style: "Hesperornis (genus Hesperornis ) ." APA style: Hesperornis (genus Hesperornis ) . style: "Hesperornis (genus Hesperornis ) ." hesperorni )

During the Eocene Epoch (57.8 to 36.6 million years ago), gars lived in Europe.... gar style:

During the Eocene Epoch (57.8 to 36.6 million years ago), gars lived in Europe as well as in North America. Gars are edible but are almost never eaten in the central and northern United States. Especially in Europe, the name gar, or garfish, or gar pike, is applied to the ( q.v. MLA style: "gar." APA style: gar. gar style:

The largest of the three species is the 100-centime.... ( m.

The largest of the three species is the 100-centimetre (40-inch) , Morus bassanus (or Sula bassana ), sometimes called solan goose; it breeds on islands in Canada, Greenland, Iceland, and northeastern Europe, wintering to the Gulf of Mexico, Morocco, and the Mediterranean. The two slightly smaller southern species are the Cape gannet ( M. capensis ), which breeds on islands off South Africa, and the Australian (or Australasian) gannet ( M. ( m.

The Everglades occupies a shallow limestone-floored basin that slopes imperceptibly southward at about 2.4 inches .... bird wade

Slight changes in the elevation of the land and the water's salt content create different habitats. Mangroves also serve as nurseries and as feeding grounds for wading birds in tidal areas where fresh and salt water combine. There are wading birds such as egrets, herons, roseate spoonbills, and ibis; shore and water birds such as terns, plovers, rails, and sandpipers; birds of prey including owls, hawks, and osprey; and a wide variety of songbirds. The population of wading birds in the Everglades has fallen drastically since the mid-20th century. bird wade

These protective tubes become encrusted with shells or are buried in sand. Ho.... horsesho worm

Horseshoe worms, or phoronids, either are solitary or occur in groups of many thousands of individuals; one species is colonial and buds asexually. Although most horseshoe worms are found intertidally or in shallow ocean regions in temperate zones, their habitats also include tropical regions and ocean depths. In general, horseshoe worms are not common; certain species, however, may carpet the bottoms of shallow bays. Since their discovery in 1846, horseshoe worms have been associated with every animal phylum, yet the relationship of horseshoe worms to other animals remains controversial. Embryological stages often are useful in relating animal groups, but the actinotroch larva of horseshoe worms is unique. On the basis of adult body form, especially similar body regions, the phoronids are grouped near the colonial moss animals (bryozoans) and the lamp shells (brachiopods). horsesho worm

In North Africa in 1954�55, excavations at Tighenif (Ternifine), east of , Algeria, yielded r.... year million

In North Africa in 195455, excavations at Tighenif (Ternifine), east of , Algeria, yielded remains dating to approximately 700,000 years ago whose nearest affinities seemed to be with the Chinese form of H. erectus in Africa came with the discovery in 1960 of a partial braincase at in Tanzania. This fossil, catalogued as OH 9, was excavated by and is probably about 1.2 million years old. The fossils recovered there may be about 1.7 million years old, based on radiometric dating of the associated volcanic material. erectus fossils discovered in Africa. year million

Among the most plentiful species of fish are cod, haddock, rosefi.... grand banks.

In 1977 Canada extended its seaward fishing claim to encompass all areas within 200 nautical miles (370 km) of its shores, including most of the Grand Banks. Agreements between Canada and other countries accustomed to fishing within Canada's newly extended coastal fisheries jurisdiction were concluded and limited the catch of foreign countries to certain more abundant species that were beyond Canada's capacity to harvest. APA style: Grand Banks. grand banks.

The brown fish owl ( K. zeylonensis ) ranges from the eastern Mediterranean to Taiwan and .... style: "fish

MLA style: "fish owl." APA style: fish owl. style: "fish owl."

The dinoflagellate cell is banded by a median or coiled groov.... dinoflagel armour

The dinoflagellate cell is banded by a median or coiled groove, the annulus, which contains a flagellum. Armoured dinoflagellates are covered with heavy, cellulose plates, which may have long, spiny extensions; some species lacking armour have a thin pellicle (protective layer). Under favourable conditions dinoflagellate populations may reach 60,000,000 organisms per litre of . APA style: dinoflagellate.

The tail of the ( Desmana moschata ) is flattened horizontally and has scent glands at i.... desman russian

The Russian desman resembles a , weighing 100220 grams (3.57.8 ounces), with a body about 20 cm (8 inches) long and a tail of about the same length. The smaller Pyrenean desman weighs 3580 grams, with a body 1114 cm long and a longer tail (1216 cm). The Russian desman is nocturnal and inhabits unpolluted lakes, ponds, and slow-moving streams and rivers. The Russian desman is indigenous to southwestern Russia, Ukraine, and Kazakhstan in basins of the , , and rivers. The nocturnal Pyrenean desman prefers cold, clear, and swift mountain streams and rivers at elevations from 300 to 2,200 metres (1,000 to 7,200 feet). During the day it shelters in crevices among stones and roots in stream banks or in burrows constructed by water . APA style: desman.

Four barrier and six secondary dams were built to close off the mouths and inner reaches of the broad, long, interco.... dam gate

When the dams were completed, fresh water from the Rhine and from other rivers gradually replaced the entrapped salt water. This dam consists of several strings of gates and their massive supporting piers and totals about 1.75 miles (2.8 km) in length. During a severe storm, however, of the type that caused the 1953 flood, the gates can be dropped to keep out high tides and storm surges and prevent them from inundating the adjacent lowlands. New roadways and connecting bridges were built over several of the Delta Project's dams and dikes, thus ending the historic isolation of the area from the rest of The Netherlands.

Male crickets chirp by rubbing a scraper located on one forewing along a row of about 50 to 250 teeth on the opposite forew.... cricket second

The frequency of the chirps depends on the number of teeth struck per second and varies from 1,500 cycles per second in the largest cricket species to nearly 10,000 cycles per second in the smallest. The most common cricket songs are the calling song, which attracts the female; the courtship, or mating, song, which induces the female to copulate; and the fighting chirp, which repels other males. The field cricket (also called the black cricket) is common in fields and yards and sometimes enters buildings. Ground crickets (subfamily Nemobiinae, or sometimes Gryllinae), approximately 12 mm long, are commonly found in pastures and wooded areas. The snowy tree cricket ( Oecanthus fultoni ) is popularly known as the thermometer cricket because the approximate temperature (Fahrenheit) can be estimated by counting the number of chirps in 15 seconds and adding 40. Tree- and bush-inhabiting crickets usually sing at night; weed-inhabiting crickets sing both day and night. Sword-bearin! g, or winged bush, crickets (subfamily Trigonidiinae) are 4 to 9 mm long and brown and possess a sword-shaped ovipositor. In East Asia male crickets are caged for their songs, and cricket fighting has been a favourite sport in China for hundreds of years. Insects called crickets but not of the cricket family Gryllidae include the camel cricket, Jerusalem cricket, mole cricket, and pygmy sand cricket.

The crater from which the lake was formed, about 6 miles (10 km) in diameter,.... feet lake

The crater from which the lake was formed, about 6 miles (10 km) in diameter, is the remnant of Mount , a volcano that rose to probably 12,000 feet (3,700 metres) until an eruption about 7,000 years ago destroyed the upper portion (see ). Crater Lake has an average surface elevation of 6,173 feet (1,881 metres) above sea level and an average depth of about 1,500 feet (457 metres). Underwater mapping of the lake in 2000 established a maximum depth of 1,943 feet (592 metres)the previous recorded maximum had been 1,932 feet (589 metres)making it the deepest lake in the United States and the seventh deepest in the world. APA style: Crater Lake.

Introduction born July 22, 1898, Lawnton, Pennsylvania, U.S. .... pennsylvania, u.s.

Introduction born July 22, 1898, Lawnton, Pennsylvania, U.S.

The Arales may share common evolutionary ancestors with the palm order (Arecales) and the Panama hat palm ....

Arales is rich in popular ornamentals and foliage plants, all in the arum, or aroid, family (Araceae). The duckweed family (Lemnaceae) is remarkable for containing the smallest known flowering plants. The largest genera in the family Araceae are (600 species); Philodendron (275 species); Arisaema (150 species), which is believed to be pollinated by snails; Homalomena (140 species); Rhaphidophora (100 species); Amorphophallus (100 species), some species of which produce inflorescences up to 1 m (about 40 inches) tall; Pothos (75 species); and Alocasia (70 species). The elephant's ear ( Colocasia esculenta ) is a variable species that includes the dasheen, , and eddo of the tropics; these plants are grown for their large edible corms, or bulblike underground stems. Species of ( Dieffenbachia ) are popular indoor foliage plants that can cause inflammation and swelling of the throat if a piece of stem is chewed. Several species of Spathiphyllum are grown as indoor potted plants.! Another beautiful foliage plant is , available in many horticultural varieties with large, colourful leaves. The family is remarkable for the smallest known flowering plants, the duckweeds ( Lemna species) and watermeals ( Wolffia species). Certain of these green, leaflike, flattened species, with or without rootlets and only a few millimetres across, are used in aquariums and pools as ornamentals or as food for waterfowl and fish.

Historical background. The earliest known aquarists were the , who kept fishes in artificial ponds at least 4,50....

The earliest known aquarists were the , who kept fishes in artificial ponds at least 4,500 years ago; records of fish keeping also date from ancient Egypt and Assyria. Although goldfish were successfully kept in glass vessels in England during the middle 1700s, aquarium keeping did not become well established until the relationship between oxygen, animals, and plants became known a century later. By 1928 there were 45 public or commercial aquariums throughout the world, but growth then slowed and few new large aquariums appeared until after World War II. The emphasis in this type of aquarium is on very large tanks, up to 1,000,000 gallons each, in which a great variety of fishes is placed with no attempt to separate them.