Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can contain suspended solid matter consisting of particles of many different sizes. While some suspended material will be large enough and heavy enough to settle to the bottom of the container if a liquid sample is left to stand small particles will settle only slowly or not at all if the sample is agitated or the particles are colloidal; these small solid particles cause the liquid to appear turbid. Turbidity is applied to transparent solids such as glass or plastic. In plastic production, haze is defined as the percentage of light, deflected more than 2.5° from the incoming light direction. Turbidity in open water may be caused by growth of phytoplankton. Human activities that disturb land, such as construction and agriculture, can lead to high sediment levels entering water bodies during rain storms due to storm water runoff.
Areas prone to high bank erosion rates as well as urbanized areas contribute large amounts of turbidity to nearby waters, through stormwater pollution from paved surfaces such as roads and parking lots. Some industries such as quarrying and coal recovery can generate high levels of turbidity from colloidal rock particles. In drinking water, the higher the turbidity level, the higher the risk that people may develop gastrointestinal diseases; this is problematic for immunocompromised people, because contaminants like viruses or bacteria can become attached to the suspended solids. The suspended solids interfere with water disinfection with chlorine because the particles act as shields for the virus and bacteria. Suspended solids can protect bacteria from ultraviolet sterilization of water. In water bodies such as lakes and reservoirs, high turbidity levels can reduce the amount of light reaching lower depths, which can inhibit growth of submerged aquatic plants and affect species which are dependent on them, such as fish and shellfish.
High turbidity levels can affect the ability of fish gills to absorb dissolved oxygen. This phenomenon has been observed throughout the Chesapeake Bay in the eastern United States. For many mangrove areas, high turbidity is needed in order to support certain species, such as to protect juvenile fish from predators. For most mangroves along the eastern coast of Australia, in particular Moreton Bay, turbidity levels as high as 600 Nephelometric Turbidity Units are needed for proper ecosystem health; the most used measurement unit for turbidity is the Formazin Turbidity Unit. ISO refers to its units as FNU. ISO 7027 provides the method in water quality for the determination of turbidity, it is used to determine the concentration of suspended particles in a sample of water by measuring the incident light scattered at right angles from the sample. The scattered light is captured by a photodiode, which produces an electronic signal, converted to a turbidity. Open source hardware has been developed following the ISO 7027 method to measure turbidity reliably using an Arduino microcontroller and inexpensive LEDs.
There are several practical ways of checking water quality, the most direct being some measure of attenuation of light as it passes through a sample column of water. The alternatively used Jackson Candle method is the inverse measure of the length of a column of water needed to obscure a candle flame viewed through it; the more water needed, the clearer the water. Of course water alone produces some attenuation, any substances dissolved in the water that produce color can attenuate some wavelengths. Modern instruments do not use candles, but this approach of attenuation of a light beam through a column of water should be calibrated and reported in JTUs; the propensity of particles to scatter a light beam focused on them is now considered a more meaningful measure of turbidity in water. Turbidity measured this way uses an instrument called a nephelometer with the detector set up to the side of the light beam. More light reaches the detector if there are lots of small particles scattering the source beam than if there are few.
The units of turbidity from a calibrated nephelometer are called Nephelometric Turbidity Units. To some extent, how much light reflects for a given amount of particulates is dependent upon properties of the particles like their shape and reflectivity. For this reason, a correlation between turbidity and total suspended solids is somewhat unusual for each location or situation. Turbidity in lakes, reservoirs and the ocean can be measured using a Secchi disk; this black and white disk is lowered into the water. The Secchi disk has the advantages of integrating turbidity over depth, being quick and easy to use, inexpensive, it can provide a rough indication of the depth of the euphotic zone with a 3-fold division of the Secchi depth, however this cannot be used in shallow waters where the disk can still be seen on the bottom. An additional device, which may help measuring turbidity in shallow waters is the turbidity tube; the turbidity tube condenses water in a graded tube which allows determination of tur
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
A chordate is an animal constituting the phylum Chordata. During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, a post-anal tail: these five anatomical features define this phylum. Chordates are bilaterally symmetric; the Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata. There are extinct taxa such as the Vetulicolia. Hemichordata has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Osteichthyes. Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically, vertebrates - chordates with the notochord replaced by a vertebral column during development - are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull.
The Craniata and Tunicata compose the clade Olfactores. Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features: A notochord, a stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, in wholly aquatic species this helps the animal to swim by flexing its tail. A dorsal neural tube. In fish and other vertebrates, this develops into the spinal cord, the main communications trunk of the nervous system. Pharyngeal slits; the pharynx is the part of the throat behind the mouth. In fish, the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live. Post-anal tail. A muscular tail that extends backwards behind the anus. An endostyle; this is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.
It stores iodine, may be a precursor of the vertebrate thyroid gland. There are soft constraints that separate chordates from certain other biological lineages, but are not part of the formal definition: All chordates are deuterostomes; this means. All chordates are based on a bilateral body plan. All chordates are coelomates, have a fluid filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm; the following schema is from the third edition of Vertebrate Palaeontology. The invertebrate chordate classes are from Fishes of the World. While it is structured so as to reflect evolutionary relationships, it retains the traditional ranks used in Linnaean taxonomy. Phylum Chordata †Vetulicolia? Subphylum Cephalochordata – Class Leptocardii Clade Olfactores Subphylum Tunicata – Class Ascidiacea Class Thaliacea Class Appendicularia Class Sorberacea Subphylum Vertebrata Infraphylum incertae sedis Cyclostomata Superclass'Agnatha' paraphyletic Class Myxini Class Petromyzontida or Hyperoartia Class †Conodonta Class †Myllokunmingiida Class †Pteraspidomorphi Class †Thelodonti Class †Anaspida Class †Cephalaspidomorphi Infraphylum Gnathostomata Class †Placodermi Class Chondrichthyes Class †Acanthodii Superclass Osteichthyes Class Actinopterygii Class Sarcopterygii Superclass Tetrapoda Class Amphibia Class Sauropsida Class Synapsida Craniates, one of the three subdivisions of chordates, all have distinct skulls.
They include the hagfish. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or all deuterostomes, are by their tails". Most craniates are vertebrates; these consist of a series of bony or cartilaginous cylindrical vertebrae with neural arches that protect the spinal cord, with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, are therefore not regarded as vertebrates, but as members of the craniates, the group from which vertebrates are thought to have evolved; however the cladistic exclusion of hagfish from the vertebrates is controversial, as they ma
Cambodia the Kingdom of Cambodia, is a country located in the southern portion of the Indochina peninsula in Southeast Asia. It is 181,035 square kilometres in area, bordered by Thailand to the northwest, Laos to the northeast, Vietnam to the east and the Gulf of Thailand to the southwest; the sovereign state of Cambodia has a population of over 16 million. The official religion is Theravada Buddhism, practised by 95 percent of the population; the country's minority groups include Vietnamese, Chams and 30 hill tribes. The capital and largest city is Phnom Penh, the political and cultural centre of Cambodia; the kingdom is an elective constitutional monarchy with a monarch Norodom Sihamoni, chosen by the Royal Throne Council as head of state. The head of government is the Prime Minister Hun Sen, the longest serving non-royal leader in Southeast Asia, ruling Cambodia since 1985. In 802 AD, Jayavarman II declared himself king, uniting the warring Khmer princes of Chenla under the name "Kambuja"; this marked the beginning of the Khmer Empire, which flourished for over 600 years, allowing successive kings to control and exert influence over much of Southeast Asia and accumulate immense power and wealth.
The Indianised kingdom facilitated the spread of first Hinduism and Buddhism to much of Southeast Asia and undertook many religious infrastructural projects throughout the region, including the construction of more than 1,000 temples and monuments in Angkor alone. Angkor Wat is designated as a World Heritage Site. After the fall of Angkor to Ayutthaya in the 15th century, a reduced and weakened Cambodia was ruled as a vassal state by its neighbours. In 1863, Cambodia became a protectorate of France, which doubled the size of the country by reclaiming the north and west from Thailand. Cambodia gained independence in 1953; the Vietnam War extended into the country with the US bombing of Cambodia from 1969 until 1973. Following the Cambodian coup of 1970 which installed the right-wing pro-US Khmer Republic, the deposed king gave his support to his former enemies, the Khmer Rouge; the Khmer Rouge emerged as a major power, taking Phnom Penh in 1975 and carrying out the Cambodian genocide from 1975 until 1979, when they were ousted by Vietnam and the Vietnamese-backed People's Republic of Kampuchea, supported by the Soviet Union in the Cambodian–Vietnamese War.
Following the 1991 Paris Peace Accords, Cambodia was governed by a United Nations mission. The UN withdrew after holding elections in which around 90 percent of the registered voters cast ballots; the 1997 factional fighting resulted in the ousting of the government by Prime Minister Hun Sen and the Cambodian People's Party, who remain in power as of 2018. Cambodia is a member of the United Nations since 1955, ASEAN, the East Asia Summit, the WTO, the Non-Aligned Movement and La Francophonie. According to several foreign organisations, the country has widespread poverty, pervasive corruption, lack of political freedoms, low human development and a high rate of hunger. Cambodia has been described by Human Rights Watch's Southeast Asian Director, David Roberts, as a "vaguely communist free-market state with a authoritarian coalition ruling over a superficial democracy". While per capita income remains low compared to most neighboring countries, Cambodia has one of the fastest growing economies in Asia, with growth averaging 7.6 percent over the last decade.
Agriculture remains the dominant economic sector, with strong growth in textiles, construction and tourism leading to increased foreign investment and international trade. The US World Justice Project's 2015 Rule of Law Index ranked Cambodia 76 out of 102 countries, similar to other countries in the region; the "Kingdom of Cambodia" is the official English name of the country. The English "Cambodia" is an anglicisation of the French "Cambodge", which in turn is the French transliteration of the Khmer កម្ពុជា kampuciə. Kampuchea is the shortened alternative to the country's official name in Khmer ព្រះរាជាណាចក្រកម្ពុជា prĕəh riəciənaacak kampuciə; the Khmer endonym Kampuchea derives from the Sanskrit name कम्बोजदेश kambojadeśa, composed of देश deśa and कम्बोज kamboja, which alludes to the foundation myths of the first ancient Khmer kingdom. The term Cambodia was in use in Europe as early as 1524, since Antonio Pigafetta cites it in his work Relazione del primo viaggio intorno al mondo as Camogia.
Colloquially, Cambodians refer to their country as either ស្រុកខ្មែរ srok khmae, meaning "Khmer's Land", or the more formal ប្រទេសកម្ពុជា prɑteih kampuciə "Country of Kampuchea". The name "Cambodia" is used most in the Western world while "Kampuchea" is more used in the East. There exists sparse evidence for a Pleistocene human occupation of present-day Cambodia, which includes quartz and quartzite pebble tools found in terraces along the Mekong River, in Stung Treng and Kratié provinces, in Kampot Province, although their dating is unreliable; some slight archaeological evidence shows communities of hunter-gatherers inhabited the region during Holocene: the most ancient archaeological discovery site in Cambodia is considered to be the cave of L'aang Spean, in Battambang Province, which belongs to the Hoabinhian period. Excavations in its lower
Fins are the most distinctive anatomical features of a fish. They are composed of bony spines or rays protruding from the body with skin covering them and joining them together, either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles, their principal function is to help. Fins located in different places on the fish serve different purposes such as moving forward, keeping an upright position or stopping. Most fish use fins when swimming, flying fish use pectoral fins for gliding, frogfish use them for crawling. Fins can be used for other purposes. For every type of fin, there are a number of fish species in which this particular fin has been lost during evolution. Bony fishes form, they have skeletons made of bone, can be contrasted with cartilaginous fishes which have skeletons made of cartilage. Bony fishes are divided into lobe-finned fish.
Most fish are ray-finned, an diverse and abundant group consisting of over 30,000 species. It is the largest class of vertebrates in existence today. In the distant past, lobe-finned fish were abundant. Nowadays they are extinct, with only eight living species. Bony fish have fin rays called lepidotrichia, they have swim bladders, which allows the fish to create a neutral balance between sinking and floating without having to use its fins. However, swim bladders are absent in many fish, most notably in Lungfishes, which are the only fish to have retained the primitive lung present in the common ancestor of bony fish from which swim bladders evolved. Bony fishes have an operculum, which helps them breathe without having to use fins to swim. Lobe-finned fishes are a class of bony fishes called Sarcopterygii, they have fleshy, paired fins, which are joined to the body by a single bone. The fins of lobe-finned fish differ from those of all other fish in that each is borne on a fleshy, scaly stalk extending from the body.
Pectoral and pelvic fins have articulations resembling those of tetrapod limbs. These fins evolved into legs of the first tetrapod land vertebrates, amphibians, they possess two dorsal fins with separate bases, as opposed to the single dorsal fin of ray-finned fish. The coelacanth is a lobe-finned fish, still extant, it is thought to have evolved into its current form about 408 million years ago, during the early Devonian. Locomotion of the coelacanths is unique to their kind. To move around, coelacanths most take advantage of up or downwellings of the current and drift, they use their paired fins to stabilize their movement through the water. While on the ocean floor their paired fins are not used for any kind of movement. Coelacanths can create thrust for quick starts by using their caudal fins. Due to the high number of fins they possess, coelacanths have high maneuverability and can orient their bodies in any direction in the water, they have been seen swimming belly up. It is thought that their rostral organ helps give the coelacanth electroperception, which aids in their movement around obstacles.
Ray-finned fishes are a class of bony fishes called Actinopterygii. Their fins contain rays. A fin may contain only soft rays, or a combination of both. If both are present, the spiny rays are always anterior. Spines are stiff and sharp. Rays are soft, flexible and may be branched; this segmentation of rays is the main difference. Spines have a variety of uses. In catfish, they are used as a form of defense. Triggerfish use spines to lock themselves in crevices to prevent them being pulled out. Lepidotrichia are bony, bilaterally paired, segmented fin rays found in bony fishes, they develop around actinotrichia as part of the dermal exoskeleton. Lepidotrichia are composed of bone, but in early osteichthyans such as Cheirolepis, there was dentine and enamel, they appear as a series of disks stacked one on top of another. The genetic basis for the formation of the fin rays is thought to be genes coded for the production of certain proteins, it has been suggested that the evolution of the tetrapod limb from lobe-finned fishes is related to the loss of these proteins.
Cartilaginous fishes are a class of fishes called Chondrichthyes. They have skeletons made of cartilage rather than bone; the class includes sharks and chimaeras. Shark fin skeletons are elongated and supported with soft and unsegmented rays named ceratotrichia, filaments of elastic protein resembling the horny keratin in hair and feathers; the pectoral and pelvic girdles, which do not contain any dermal elements, did not connect. In forms, each pair of fins became ventrally connected in the middle when scapulocoracoid and pubioischiadic bars evolved. In rays, the pectoral fins have connected to the head and are flexible. One of the primary characteristics present in most sharks is the heterocercal tail, which aids in locomotion. Most sharks have eight fins. Sharks can only drift away from objects directly in front of them because
Sumatra is a large island in western Indonesia, part of the Sunda Islands. It is the largest island, located in Indonesia and the sixth-largest island in the world at 473,481 km2. Sumatra is an elongated landmass spanning a diagonal northwest-southeast axis; the Indian Ocean borders the west and southwest coasts of Sumatra with the island chain of Simeulue and Mentawai off the western coast. In the northeast the narrow Strait of Malacca separates the island from the Malay Peninsula, an extension of the Eurasian continent. In the southeast the narrow Sunda Strait separates Sumatra from Java; the northern tip of Sumatra borders the Andaman Islands, while off the southeastern coast lie the islands of Bangka and Belitung, Karimata Strait and the Java Sea. The Bukit Barisan mountains, which contain several active volcanoes, form the backbone of the island, while the northeastern area contains large plains and lowlands with swamps, mangrove forest and complex river systems; the equator crosses the island at its center in West Riau provinces.
The climate of the island is tropical and humid. Lush tropical rain forest once dominated the landscape. Sumatra has a wide range of plant and animal species but has lost 50% of its tropical rainforest in the last 35 years. Many species are now critically endangered, such as the Sumatran ground cuckoo, the Sumatran tiger, the Sumatran elephant, the Sumatran rhinoceros, the Sumatran orangutan. Deforestation on the island has resulted in serious seasonal smoke haze over neighbouring countries, such as the 2013 Southeast Asian haze causing considerable tensions between Indonesia and affected countries Malaysia and Singapore. Sumatra was known in ancient times by the Sanskrit names of Swarnadwīpa and Swarnabhūmi, because of the gold deposits in the island's highlands; the first mention of the name of Sumatra was in the name of Srivijayan Haji Sumatrabhumi, who sent an envoy to China in 1017. Arab geographers referred to the island as Lamri in the tenth through thirteenth centuries, in reference to a kingdom near modern-day Banda Aceh, the first landfall for traders.
The island is known by other names namely, Andalas or Percha Island. Late in the 14th century the name Sumatra became popular in reference to the kingdom of Samudra Pasai, a rising power until replaced by the Sultanate of Aceh. Sultan Alauddin Shah of Aceh, in letters addressed to Queen Elizabeth I of England in 1602, referred to himself as "king of Aceh and Samudra"; the word itself is from Sanskrit "Samudra", meaning "gathering together of waters, sea or ocean". Marco Polo named the kingdom Samara or Samarcha in the late 13th century, while the 14th century traveller Odoric of Pordenone used Sumoltra for Samudra. Subsequent European writers used similar forms of the name for the entire island. European writers in the 19th century found that the indigenous inhabitants did not have a name for the island; the Melayu Kingdom was absorbed by Srivijaya. Srivijayan influence waned in the 11th century after it was defeated by the Chola Empire of southern India. At the same time, Islam made its way to Sumatra through Arabs and Indian traders in the 6th and 7th centuries AD.
By the late 13th century, the monarch of the Samudra kingdom had converted to Islam. Marco Polo visited the island in 1292. Ibn Battuta visited with the sultan for 15 days, noting the city of Samudra was "a fine, big city with wooden walls and towers," and another 2 months on his return journey. Samudra was succeeded by the powerful Aceh Sultanate. With the coming of the Dutch, the many Sumatran princely states fell under their control. Aceh, in the north, was the major obstacle, as the Dutch were involved in the long and costly Aceh War; the Free Aceh Movement fought against Indonesian government forces in the Aceh Insurgency from 1976 to 2005. Security crackdowns in 2001 and 2002 resulted in several thousand civilian deaths; the longest axis of the island runs 1,790 km northwest–southeast, crossing the equator near the centre. At its widest point, the island spans 435 km; the interior of the island is dominated by two geographical regions: the Barisan Mountains in the west and swampy plains in the east.
Sumatra is the closest Indonesian island to mainland Asia. To the southeast is Java, separated by the Sunda Strait. To the north is the Malay Peninsula, separated by the Strait of Malacca. To the east is Borneo, across the Karimata Strait. West of the island is the Indian Ocean; the Great Sumatran fault, the Sunda megathrust, run the entire length of the island along its west coast. On 26 December 2004, the western coast and islands of Sumatra Aceh province, were struck by a tsunami following the Indian Ocean earthquake; this was the longest earthquake recorded, lasting between 600 seconds. More than 170,000 Indonesians were killed in Aceh. Other recent earthquakes to strike Sumatra include the 2005 Nias–Simeulue earthquake and the 2010 Mentawai earthquake and tsunami. To the east, big rivers carry silt from the mountains, forming the vast lowland interspersed by swamps. If unsuitable for farming, the area is of great economic importance for Indonesia, it produces oil from both above and below the soil -- petroleum.
Sumatra is the largest producer of Indonesian coffee. Small-holders grow Arabica coffee in the highlands, while Rob
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi