In ecology, a habitat is the type of natural environment in which a particular species of organism lives. It is characterized by both biological features. A species' habitat is those places where it can find food, shelter and mates for reproduction; the physical factors are for example soil, range of temperature, light intensity as well as biotic factors such as the availability of food and the presence or absence of predators. Every organism has certain habitat needs for the conditions in which it will thrive, but some are tolerant of wide variations while others are specific in their requirements. A habitat is not a geographical area, it can be the interior of a stem, a rotten log, a rock or a clump of moss, for a parasitic organism it is the body of its host, part of the host's body such as the digestive tract, or a single cell within the host's body. Habitat types include polar, temperate and tropical; the terrestrial vegetation type may be forest, grassland, semi-arid or desert. Fresh water habitats include marshes, rivers and ponds, marine habitats include salt marshes, the coast, the intertidal zone, reefs, the open sea, the sea bed, deep water and submarine vents.
Habitats change over time. This may be due to a violent event such as the eruption of a volcano, an earthquake, a tsunami, a wildfire or a change in oceanic currents. Other changes come as a direct result of human activities; the introduction of alien species can have a devastating effect on native wildlife, through increased predation, through competition for resources or through the introduction of pests and diseases to which the native species have no immunity. The word "habitat" has been in use since about 1755 and derives from the Latin habitāre, to inhabit, from habēre, to have or to hold. Habitat can be defined as the natural environment of an organism, the type of place in which it is natural for it to live and grow, it is similar in meaning to a biotope. The chief environmental factors affecting the distribution of living organisms are temperature, climate, soil type and light intensity, the presence or absence of all the requirements that the organism needs to sustain it. Speaking, animal communities are reliant on specific types of plant communities.
Some plants and animals are generalists, their habitat requirements are met in a wide range of locations. The small white butterfly for example is found on all the continents of the world apart from Antarctica, its larvae feed on a wide range of Brassicas and various other plant species, it thrives in any open location with diverse plant associations. The large blue butterfly is much more specific in its requirements. Disturbance is important in the creation of biodiverse habitats. In the absence of disturbance, a climax vegetation cover develops that prevents the establishment of other species. Wildflower meadows are sometimes created by conservationists but most of the flowering plants used are either annuals or biennials and disappear after a few years in the absence of patches of bare ground on which their seedlings can grow. Lightning strikes and toppled trees in tropical forests allow species richness to be maintained as pioneering species move in to fill the gaps created. Coastal habitats can become dominated by kelp until the seabed is disturbed by a storm and the algae swept away, or shifting sediment exposes new areas for colonisation.
Another cause of disturbance is when an area may be overwhelmed by an invasive introduced species, not kept under control by natural enemies in its new habitat. Terrestrial habitat types include forests, grasslands and deserts. Within these broad biomes are more specific habitats with varying climate types, temperature regimes, soils and vegetation types. Many of these habitats grade into each other and each one has its own typical communities of plants and animals. A habitat may suit a particular species well, but its presence or absence at any particular location depends to some extent on chance, on its dispersal abilities and its efficiency as a coloniser. Freshwater habitats include rivers, lakes, ponds and bogs. Although some organisms are found across most of these habitats, the majority have more specific requirements; the water velocity, its temperature and oxygen saturation are important factors, but in river systems, there are fast and slow sections, pools and backwaters which provide a range of habitats.
Aquatic plants can be floating, semi-submerged, submerged or grow in permanently or temporarily saturated soils besides bodies of water. Marginal plants provide important habitat for both invertebrates and vertebrates, submerged plants provide oxygenation of the water, absorb nutrients and play a part in the reduction of pollution. Marine habitats include brackish water, bays, the open sea, the intertidal zone, the sea bed and deep / shallow water zones. Further variations include rock pools, sand banks, brackish lagoons and pebbly beaches, seagrass beds, all supporting their own flora and fauna; the benth
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size. Colonial nesting birds include seabirds such as albatrosses. A group of birds congregating for rest is called a communal roost. Evidence of colonial nesting has been found in non-neornithine birds, in sediments from the Late Cretaceous of Romania. 13% of all bird species nest colonially. Nesting colonies are common among seabirds on cliffs and islands. Nearly 95% of seabirds are colonial, leading to the usage, seabird colony, sometimes called a rookery. Many species of terns nest in colonies on the ground. Herons, egrets and other large waterfowl nest communally in what are called heronries. Colony nesting may be an evolutionary response to a shortage of safe nesting sites and abundance or unpredictable food sources which are far away from the nest sites. Colony-nesting birds show synchrony in their breeding, meaning that chicks all hatch at once, with the implication that any predator coming along at that time would find more prey items than it could eat.
What constitutes a colony is a matter of definition. Tufted puffins, for example, are pelagic birds that nest on the steep slopes and rocky crevices on coastal cliffs on islands; each pair excavates its own burrow. A congregation of puffin burrows on a marine island is considered a colony. Sand martins are if observed to nest in solitude. A more extreme example of colonial nesting is found in the weaverbird family; the sociable weaver of southern Africa constructs massive, multi-family dwellings of twigs and dry grasses, with many entrances leading to different nesting chambers, accommodating as many as a hundred nesting pairs. These structures resemble haystacks hanging from trees, have been likened to apartment buildings or beehives; some seabird colonies host thousands of nesting pairs of various species. Triangle Island, for example, the largest seabird colony in British Columbia, Canada, is home to auks, cormorants and other birds, as well as some marine mammals. Many seabirds show remarkable site fidelity, returning to the same burrow, nest or site for many years, they will defend that site from rivals with great vigour.
This increases breeding success, provides a place for returning mates to reunite, reduces the costs of prospecting for a new site. Young adults breeding for the first time return to their natal colony, nest close to where they hatched. Individual nesting sites at seabird colonies can be spaced, as in an albatross colony, or densely packed like an auk colony. In most seabird colonies several different species will nest on the same colony exhibiting some niche separation. Seabirds can nest in trees, on the ground, on cliffs, in burrows under the ground and in rocky crevices. Colony size is a major aspect of the social environment of colonial birds; some birds are known to nest in colonies when conditions are suitable, but not always. The white-winged dove of southwestern North America was known to nest in large colonies when foraging areas could support such numbers. In 1978, in Tamaulipas, researchers counted 22 breeding colonies of white-winged doves with a collective population size of more than eight million birds.
But as habitat was transformed through urbanization or agriculture, the doves spread out into smaller, less long-lived colonies. Today, these doves are observed to nest colonially in both urban and rural areas; the term colony has been applied misleadingly, to smaller nesting groups, such as forest-dwelling species that nest in a suitable stand of trees. The red-cockaded woodpecker, an endangered species of southeastern North America, is a social species that feeds and roosts in family groups, or clans. Clans nest and roost in clusters of tree cavities and use a cooperative breeding system. Many parrot species are extremely social. For example, the thick-billed parrot is another bird that roosts communally. However, these complex social structures in birds are a different sort of group behavior than what is considered colonial; the habit of nesting in groups is believed to provide better survival against predators in several ways. Many colonies are situated in locations that are free of predators.
In other cases, the presence of many birds means. Synchronized breeding leads to such an abundance of offspring as to satiate predators. For seabirds, colonies on islands have an obvious advantage over mainland colonies when it comes to protection from terrestrial predators. Other situations can be found where bird colonies avoid predation. A study of yellow-rumped caciques in Peru found that the birds, which build enclosed, pouch-like nests in colonies of up to one hundred active nests, situate themselves near wasp nests, which provide some protection from tree-dwelling predators such as monkeys; when other birds came to rob the nests, the caciques would cooperatively defend the colony by mobbing the invader. Mobbing a group effort, is well-known behavior, not limited to col
Ecuador the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, the Pacific Ocean to the west. Ecuador includes the Galápagos Islands in the Pacific, about 1,000 kilometres west of the mainland; the capital city is Quito, the largest city. What is now Ecuador was home to a variety of Amerindian groups that were incorporated into the Inca Empire during the 15th century; the territory was colonized by Spain during the 16th century, achieving independence in 1820 as part of Gran Colombia, from which it emerged as its own sovereign state in 1830. The legacy of both empires is reflected in Ecuador's ethnically diverse population, with most of its 16.4 million people being mestizos, followed by large minorities of European and African descendants. Spanish is the official language and is spoken by a majority of the population, though 13 Amerindian languages are recognized, including Quichua and Shuar; the sovereign state of Ecuador is a middle-income representative democratic republic with a developing economy, dependent on commodities, namely petroleum and agricultural products.
It is governed as a democratic presidential republic. One of 18 megadiverse countries in the world, Ecuador hosts many endemic plants and animals, such as those of the Galápagos Islands. In recognition of its unique ecological heritage, the new constitution of 2008 is the first in the world to recognize enforceable Rights of Nature, or ecosystem rights, it has the fifth lowest homicide rate in the Americas. Various peoples had settled in the area of the future Ecuador before the arrival of the Incas; the archeological evidence suggests that the Paleo-Indians' first dispersal into the Americas occurred near the end of the last glacial period, around 16,500–13,000 years ago. The first Indians who reached Ecuador may have journeyed by land from North and Central America or by boat down the Pacific Ocean coastline. Much migrations to Ecuador may have come via the Amazon tributaries, others descended from northern South America, others ascended from the southern part of South America through the Andes.
They developed different languages while emerging as unique ethnic groups. Though their languages were unrelated, these groups developed similar groups of cultures, each based in different environments; the people of the coast developed a fishing and gathering culture. Over time these groups began to interact and intermingle with each other so that groups of families in one area became one community or tribe, with a similar language and culture. Many civilizations arose in Ecuador, such as the Valdivia Culture and Machalilla Culture on the coast, the Quitus, the Cañari; each civilization developed its own distinctive architecture and religious interests. In the highland Andes mountains, where life was more sedentary, groups of tribes cooperated and formed villages. Through wars and marriage alliances of their leaders, a group of nations formed confederations. One region consolidated under a confederation called the Shyris, which exercised organized trading and bartering between the different regions.
Its political and military power came under the rule of the Duchicela blood-line. When the Incas arrived, they found that these confederations were so developed that it took the Incas two generations of rulers—Topa Inca Yupanqui and Huayna Capac—to absorb them into the Inca Empire; the native confederations that gave them the most problems were deported to distant areas of Peru and north Argentina. A number of loyal Inca subjects from Peru and Bolivia were brought to Ecuador to prevent rebellion. Thus, the region of highland Ecuador became part of the Inca Empire in 1463 sharing the same language. In contrast, when the Incas made incursions into coastal Ecuador and the eastern Amazon jungles of Ecuador, they found both the environment and indigenous people more hostile. Moreover, when the Incas tried to subdue them, these indigenous people withdrew to the interior and resorted to guerrilla tactics; as a result, Inca expansion into the Amazon Basin and the Pacific coast of Ecuador was hampered.
The indigenous people of the Amazon jungle and coastal Ecuador remained autonomous until the Spanish soldiers and missionaries arrived in force. The Amazonian people and the Cayapas of Coastal Ecuador were the only groups to resist Inca and Spanish domination, maintaining their language and culture well into the 21st century. Before the arrival of the Spaniards, the Inca Empire was involved in a civil war; the untimely death of both the heir Ninan Cuchi and the Emperor Huayna Capac, from a European disease that spread into Ecuador, created a power vacuum between two factions. The northern faction headed by Atahualpa claims that Huayna Capac gave a verbal decree before his death about how the empire should be divided, he gave the territories pertaining to present-day Ecuador and northern Peru to his favorite son Atahualpa, to rule from Quito. He willed that his heart be buried in Quito, his favorite city, the rest of his body be buried with his ancestors in Cuzco. Huáscar did not recognize his fa
The breast is one of two prominences located on the upper ventral region of the torso of primates. In females, it serves as the mammary gland, which secretes milk to feed infants. Both females and males develop breasts from the same embryological tissues. At puberty, estrogens, in conjunction with growth hormone, cause breast development in female humans and to a much lesser extent in other primates. Breast development in other primate females only occurs with pregnancy. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple, these tissues give the breast its size and shape. At the ends of the ducts are lobules, or clusters of alveoli, where milk is produced and stored in response to hormonal signals. During pregnancy, the breast responds to a complex interaction of hormones, including estrogens and prolactin, that mediate the completion of its development, namely lobuloalveolar maturation, in preparation of lactation and breastfeeding. Along with their major function in providing nutrition for infants, female breasts have social and sexual characteristics.
Breasts have been featured in notable ancient and modern sculpture and photography. They can figure prominently in the perception of a woman's body and sexual attractiveness. A number of Western cultures associate breasts with sexuality and tend to regard bare breasts in public as immodest or indecent. Breasts the nipples, are an erogenous zone; the English word breast derives from the Old English word brēost from Proto-Germanic breustam, from the Proto-Indo-European base bhreus–. The breast spelling conforms to the North English dialectal pronunciations; the Merriam-Webster Dictionary states. Old Irish brú, Russian bryukho". A large number of colloquial terms for breasts are used in English, ranging from polite terms to vulgar or slang; some vulgar slang expressions may be considered to be sexist to women. In women, the breasts overlie the pectoralis major muscles and extend from the level of the second rib to the level of the sixth rib in the front of the human rib cage. At the front of the chest, the breast tissue can extend from the clavicle to the middle of the sternum.
At the sides of the chest, the breast tissue can extend into the axilla, can reach as far to the back as the latissimus dorsi muscle, extending from the lower back to the humerus bone. As a mammary gland, the breast is composed of differing layers of tissue, predominantly two types: adipose tissue. Morphologically the breast is tear-shaped; the superficial tissue layer is separated from the skin by 0.5–2.5 cm of subcutaneous fat. The suspensory Cooper's ligaments are fibrous-tissue prolongations that radiate from the superficial fascia to the skin envelope; the female adult breast contains 14–18 irregular lactiferous lobes that converge at the nipple. The 2.0–4.5 mm milk ducts are surrounded with dense connective tissue that support the glands. Milk exits the breast through the nipple, surrounded by a pigmented area of skin called the areola; the size of the areola can vary among women. The areola contains modified sweat glands known as Montgomery's glands; these glands secrete oily fluid that protect the nipple during breastfeeding.
Volatile compounds in these secretions may serve as an olfactory stimulus for the newborn's appetite. The dimensions and weight of the breast vary among women. A small-to-medium-sized breast weighs 500 grams or less, a large breast can weigh 750 to 1,000 grams or more; the tissue composition ratios of the breast vary among women. Some women's breasts have varying proportions of glandular tissue than of adipose or connective tissues; the fat-to-connective-tissue ratio determines the firmness of the breast. During a woman's life, her breasts change size and weight due to hormonal changes during puberty, the menstrual cycle, pregnancy and menopause; the breast is an apocrine gland. The nipple of the breast is surrounded by the areola; the areola has many sebaceous glands, the skin color varies from pink to dark brown. The basic units of the breast are the terminal duct lobular units, which produce the fatty breast milk, they give the breast its offspring-feeding functions as a mammary gland. They are distributed throughout the body of the breast.
Two-thirds of the lactiferous tissue is within 30 mm of the base of the nipple. The terminal lactiferous ducts drain the milk from TDLUs into 4–18 lactiferous ducts, which drain to the nipple; the milk-glands-to-fat ratio is 2:1 in a lactating woman, 1:1 in a non-lactating woman. In addition to the milk glands, the breast is composed of connective tissues, white fat, the suspensory Cooper's ligaments. Sensation in the breast is provided by the peripheral nervous system innervation by means of the front and side cutaneous branches of the fourth-, fifth-, sixth intercostal nerves; the T-4 nerve, which innervates the dermatomic area, supplies sensation to the nipple-areola complex. 75% of the lymph from the breast travels to the axillary lymph nodes on the same side of the body, w
Patagonia is a sparsely populated region at the southern end of South America, shared by Chile and Argentina. The region comprises the southern section of the Andes mountains and the deserts and grasslands to the east. Patagonia is one of the few regions with coasts on three oceans, with the Pacific Ocean to the west, the Atlantic Ocean to the east, the Southern Ocean to the south; the Colorado and Barrancas rivers, which run from the Andes to the Atlantic, are considered the northern limit of Argentine Patagonia. The archipelago of Tierra del Fuego is sometimes included as part of Patagonia. Most geographers and historians locate the northern limit of Chilean Patagonia at Huincul Fault, in Araucanía Region; the name Patagonia comes from the word patagón, used by Magellan in 1520 to describe the native tribes of the region, whom his expedition thought to be giants. It is now believed that the people he called the Patagons were Tehuelches, who tended to be taller than Europeans of the time; the Argentine researcher Miguel Doura observed that the name Patagonia derives from the ancient Greek region of modern Turkey called Paphlagonia, possible home of the patagon personage in the chivalric romances Primaleon printed in 1512, ten years before Magellan arrived in these southern lands.
The hypothesis was published in a 2011 New Review of Spanish Philology report. Argentine Patagonia is for the most part a region of steppelike plains, rising in a succession of 13 abrupt terraces about 100 metres at a time, covered with an enormous bed of shingle bare of vegetation. In the hollows of the plains are ponds or lakes of fresh and brackish water. Towards Chilean territory the shingle gives place to porphyry and basalt lavas, animal life becomes more abundant and vegetation more luxuriant, consisting principally of southern beech and conifers; the high rainfall against the western Andes and the low sea surface temperatures offshore give rise to cold and humid air masses, contributing to the ice-fields and glaciers, the largest ice-fields in the Southern hemisphere outside of Antarctica. Among the depressions by which the plateau is intersected transversely, the principal ones are the Gualichu, south of the Río Negro, the Maquinchao and Valcheta, the Senguerr, the Deseado River. Besides these transverse depressions, there are others which were occupied by more or less extensive lakes, such as the Yagagtoo and Colhue Huapi, others situated to the south of Puerto Deseado, in the centre of the country.
In the central region volcanic eruptions, which have taken part in the formation of the plateau during the Cenozoic, cover a large part of the land with basaltic lava-caps. There, caused principally by the sudden melting and retreat of ice aided by tectonic changes, has scooped out a deep longitudinal depression, best in evidence where in contact with folded Cretaceous rocks which are uplifted by the Cenozoic granite, it separates the plateau from the first lofty hills, whose ridges are called the pre-Cordillera. To the west of these, a similar longitudinal depression extends all along the foot of the snowy Andean Cordillera; this latter depression contains the richest and most fertile land of Patagonia. Lake basins along the Cordillera were excavated by ice-streams, including Lake Argentino and Lake Fagnano, as well as coastal bays such as Bahía Inútil; the geological limit of Patagonia has been proposed to be Huincul Fault which forms a major discontinuity. The fault truncates various structures including the Pampean orogen found further north.
The ages of base arocks change abruptly across the fault. There have been discrepancies among geologists on the origin of the Patagonian landmass. Víctor Ramos has proposed that the Patagonian landmass originated as an allochthonous terrane that separated from Antarctica and docked in South America 250 to 270 Ma in the Permian era. A 2014 study by R. J. Pankhurst and coworkers rejects any idea of a far-travelled Patagonia claiming it is of parautochtonous origin; the Mesozoic and Cenozoic deposits have revealed a most interesting vertebrate fauna. This, together with the discovery of the perfect cranium of a chelonian of the genus Niolamia, identical with Ninjemys oweni of the Pleistocene age in Queensland, forms an evident proof of the connection between the Australian and South American continents; the Patagonian Niolamia belongs to the Sarmienti Formation. Fossils of the mid-Cretaceous Argentinosaurus, which may be the largest of all dinosaurs, have been found in Patagonia, a model of the mid-Jurassic Piatnitzkysaurus graces the concourse of the Trelew airport.
Of more than paleontological interest, the middle Jurassic Los Molles Formation and the still richer late Jurassic and early Cretaceous Vaca Muerta formation above it in the Neuquén basin are reported to contain huge hydrocarbon reserves accessible through hydraulic fracturing. Other specimens of the interesting fauna of Patagonia, belonging to the Middle Cenozoic, are the gigantic wingless birds, exceeding in size any hitherto known, the singular mammal Pyrotherium of large dimensions. In