Edward S. Morse
Edward Sylvester Morse was an American zoologist and orientalist. Morse was born in Portland, Maine as the son of a Congregationalist deacon who held strict Calvinist beliefs, his mother, who did not share her husband's religious beliefs, encouraged her son's interest in the sciences. An unruly student, Morse was expelled from every school he attended in his youth — the Portland village school, the academy at Conway, New Hampshire, in 1851, Bridgton Academy in 1854, he attended Gould Academy in Bethel, Maine. At Gould Academy, Morse came under the influence of Dr. Nathaniel True who encouraged Morse to pursue his interest in the study of nature, he preferred to explore the Atlantic coast in search of shells and snails, or go to the field to study the fauna and flora. However, despite his lack of formal education, the collections formed during adolescence soon earned him the visit of eminent scientists from Boston and the United Kingdom, he was noted for his work with land snails, before the age of twelve when he had discovered two new species: Helix Milium and H. astericus.
As a young man, he worked as a mechanical draftsman at the Portland Locomotive Company and a wood engraver attached to a Boston company. Morse was recommended by Philip Pearsall Carpenter to Louis Agassiz at the Museum of Comparative Zoology at Harvard University for his intellectual qualities and talent at drawing, served as his assistant in charge of conservation and drawing collections of mollusks and brachiopods until 1861. During the American Civil War, Morse attempted to enlist in the 25th Maine Infantry, but was turned down due to a chronic tonsil infection. On June 18, 1863, Morse married Ellen Elizabeth Owen in Portland; the couple had Edith Owen Morse and John Gould Morse. Morse became successful in the field of zoology, specializing in malacology or the study of mollusks. In March 1863, along with three other students of Agassiz, Morse co-founded the scientific journal The American Naturalist, he became one of its editors; the journal included a large number of his drawings. In 1864, he published his first work devoted to mollusks under the title Observations On The Terrestrial Pulmonifera of Maine, Including a Catalogue of All the Species of Terrestrial Mollusca and Fluvial Known to Inhabit the State.
In 1870 he published The Brachiopods, a Division of the Annelida wherein he reclassified brachiopods as worms rather than mollusks. The work attracted the attention of Charles Darwin. From 1871 to 1874, Morse was appointed to the chair of comparative anatomy and zoology at Bowdoin College. In 1874, he became a lecturer at Harvard University. In 1876, Morse was named a fellow of the National Academy of Science. In June 1877 Morse first visited Japan in search of coastal brachiopods, his visit turned into a three-year stay when he was offered a post as the first professor of Zoology at the Tokyo Imperial University. He went on to recommend several fellow Americans as o-yatoi gaikokujin to support the modernization of Japan in the Meiji Era. To collect specimens, he established a marine biological laboratory at Enoshima in Kanagawa Prefecture. While looking out of a window on a train between Yokohama and Tokyo, Morse discovered the Ōmori shell mound, the excavation of which opened the study in archaeology and anthropology in Japan and shed much light on the material culture of prehistoric Japan.
He returned to Japan in 1881 to present a report of his findings to Tokyo Imperial University. While in Japan, he authored a book Japanese Homes and Their Surroundings illustrated with his own line drawings, he made a collection of over 5,000 pieces of Japanese pottery. He devised the term "cord-marked" for the sherds of Stone Age pottery, decorated by impressing cords into the wet clay; the Japanese translation, "Jōmon," now gives its name to the whole Jōmon period as well as Jōmon pottery. Morse had much interest in Japanese ceramics, he returned on a third visit to Japan in 1882, during which he collected clay samples as well as finished ceramics. He brought back to Boston a collection amassed by government minister and amateur art collector Ōkuma Shigenobu, who donated it to Morse in recognition of his services to Japan; these now form part of the "Morse Collection" of Museum of Fine Arts in Boston, whose catalog was written by Ernest Francisco Fenollosa. His collection of daily artifacts of the Japanese people is kept at the Peabody Essex Museum in Salem, Massachusetts.
The remainder of the collection was inherited by his granddaughter, Catharine Robb Whyte via her mother Edith Morse Robb and is housed at the Whyte Museum of the Canadian Rockies, Alberta, Canada. After leaving Japan, Morse traveled to Southeast Europe. In 1884, he was elected a vice president of the American Association for the Advancement of Science, became president of that association in 1886, 1887, 1888, 1889. During this period, he returned to Europe, Japan in quest of pottery. Morse became Keeper of Pottery at the Museum of Fine Arts, Boston in 1890, he was a director of the Peabody Academy of Science in Salem from 1880 to 1914. In 1898, he was awarded the Order of the Rising Sun by the Japanese government, he was elected a member of the American Antiquarian Society in 1898. He became chairman of the Boston Museum in 1914, chairman of the Peabody Museum in 1915, he was awarded the Order of the Sacred Treasures by the Japanese government in 1922. Morse was a friend of astronomer Percival Lowell.
Morse would journey to the Lowell
Rammed earth known as taipa in Portuguese, tapial or tapia in Spanish, pisé in French, hangtu, is a technique for constructing foundations and walls using natural raw materials such as earth, lime, or gravel. It is an ancient method, revived as a sustainable building material used in a technique of natural building. Rammed earth is simple to manufacture, non-combustible, thermally massive and durable. However, structures such as walls can be laborious to construct of rammed earth without machinery, e. g. powered tampers, they are susceptible to water damage if inadequately protected or maintained. Edifices formed of rammed earth are on every continent except Antarctica, in a range of environments including temperate, semiarid desert and tropical regions; the availability of suitable soil and a building design appropriate for local climatic conditions are the factors that favour its use. Manufacturing rammed earth involves compressing a damp mixture of earth that has suitable proportions of sand, clay, and/or an added stabilizer into an externally supported frame or mold, forming either a solid wall or individual blocks.
Additives such as lime or animal blood were used to stabilize it, while modern construction adds lime, cement, or asphalt emulsions. To add variety, some modern builders add coloured oxides or other materials, e.g. bottles, tires, or pieces of timber. The construction of an entire wall begins with a temporary frame, denominated the "formwork", made of wood or plywood, as a mold for the desired shape and dimensions of each section of wall; the form must be durable and well braced, the two opposing faces must be clamped together to prevent bulging or deformation caused by the large compressing forces. Damp material is poured into the formwork to a depth of 10 to 25 cm and compacted to 50% of its original height; the material is compressed iteratively, in batches or courses, so as to erect the wall up to the top of the formwork. Tamping was manual with a long ramming pole, was laborious, but modern construction can be made less so by employing pneumatically powered tampers. After a wall is complete, it is sufficiently strong to remove the formwork.
This is necessary if a surface texture is to be applied, e.g. by wire brushing, carving, or mold impression, because the walls become too hard to work after one hour. Construction is optimally done in warm weather so that the walls can harden; the compression strength of the rammed earth increases. Exposed walls must be sealed to prevent water damage. In modern variations of the technique, rammed-earth walls are constructed on top of conventional footings or a reinforced concrete slab base. Where blocks made of rammed earth are used, they are stacked like regular blocks and are bonded together with a thin mud slurry instead of cement. Special machines powered by small engines and portable, are used to compress the material into blocks. Presently more than 30% of the world's population uses earth as a building material. Rammed earth has been used globally in a wide range of climatic conditions. Rammed-earth housing may resolve homelessness caused by otherwise expensive construction techniques; the compressive strength of rammed earth is a maximum of 4.3 MPa.
This is more than sufficiently strong for domestic edifices. Indeed, properly constructed rammed earth endures for thousands of years, as many ancient structures that are still standing around the world demonstrate. Rammed earth reinforced with rebar, wood, or bamboo can prevent collapse caused by earthquakes or heavy storms, because unreinforced edifices of rammed earth resist earthquake damage poorly. See 1960 Agadir earthquake for an example of the total destruction which may be inflicted on such structures by an earthquake. Adding cement to soil mixtures poor in clay can increase the load-bearing capacity of rammed-earth edifices; the United States Department of Agriculture observed in 1925 that rammed-earth structures endure indefinitely and can be constructed for less than two-thirds of the cost of standard frame houses. Soil is a available and sustainable resource. Therefore, construction with rammed earth is viable. Unskilled labour can do most of the necessary work. While the cost of rammed earth is low, rammed-earth construction without mechanical tools is time-consuming and laborious.
One significant benefit of rammed earth is its high thermal mass: like brick or concrete, it can absorb heat during daytime and nocturnally release it. This action moderates daily temperature variations and reduces the need for air conditioning and heating. In colder climates, rammed-earth walls can be insulated with a similar insert, it must be protected from heavy rain and insulated with vapour barriers. Rammed earth can regulate humidity if unclad walls containing clay are exposed to an internal space. Humidity is regulated between 40% and 60%, the ideal range for asthma sufferers and for the storage of susceptible objects such as books; the material mass and clay content of rammed earth allows an edifice to breathe more than concrete edifices, which avoids problems of condensation but prevents significant loss of heat. Untouched, rammed-earth w
Ultraviolet designates a band of the electromagnetic spectrum with wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation is present in sunlight, contributes about 10% of the total light output of the Sun, it is produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce; the chemical and biological effects of UV are greater than simple heating effects, many practical applications of UV radiation derive from its interactions with organic molecules. Suntan and sunburn are familiar effects of over-exposure of the skin to UV, along with higher risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earth's atmosphere.
More energetic, shorter-wavelength "extreme" UV below 121 nm ionizes air so that it is absorbed before it reaches the ground. Ultraviolet is responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans; the UV spectrum thus has effects both harmful to human health. The lower wavelength limit of human vision is conventionally taken as 400 nm, so ultraviolet rays are invisible to humans, although some people can perceive light at shorter wavelengths than this. Insects and some mammals can see near-UV. Ultraviolet rays are invisible to most humans; the lens of the human eye blocks most radiation in the wavelength range of 300–400 nm. Humans lack color receptor adaptations for ultraviolet rays; the photoreceptors of the retina are sensitive to near-UV, people lacking a lens perceive near-UV as whitish-blue or whitish-violet. Under some conditions and young adults can see ultraviolet down to wavelengths of about 310 nm. Near-UV radiation is visible to insects, some mammals, birds.
Small birds have a fourth color receptor for ultraviolet rays. "Ultraviolet" means "beyond violet", violet being the color of the highest frequencies of visible light. Ultraviolet has a higher frequency than violet light. UV radiation was discovered in 1801 when the German physicist Johann Wilhelm Ritter observed that invisible rays just beyond the violet end of the visible spectrum darkened silver chloride-soaked paper more than violet light itself, he called them "oxidizing rays" to emphasize chemical reactivity and to distinguish them from "heat rays", discovered the previous year at the other end of the visible spectrum. The simpler term "chemical rays" was adopted soon afterwards, remained popular throughout the 19th century, although some said that this radiation was different from light; the terms "chemical rays" and "heat rays" were dropped in favor of ultraviolet and infrared radiation, respectively. In 1878 the sterilizing effect of short-wavelength light by killing bacteria was discovered.
By 1903 it was known. In 1960, the effect of ultraviolet radiation on DNA was established; the discovery of the ultraviolet radiation with wavelengths below 200 nm, named "vacuum ultraviolet" because it is absorbed by the oxygen in air, was made in 1893 by the German physicist Victor Schumann. The electromagnetic spectrum of ultraviolet radiation, defined most broadly as 10–400 nanometers, can be subdivided into a number of ranges recommended by the ISO standard ISO-21348: A variety of solid-state and vacuum devices have been explored for use in different parts of the UV spectrum. Many approaches seek to adapt visible light-sensing devices, but these can suffer from unwanted response to visible light and various instabilities. Ultraviolet can be detected by suitable photodiodes and photocathodes, which can be tailored to be sensitive to different parts of the UV spectrum. Sensitive ultraviolet photomultipliers are available. Spectrometers and radiometers are made for measurement of UV radiation.
Silicon detectors are used across the spectrum. Vacuum UV, or VUV, wavelengths are absorbed by molecular oxygen in the air, though the longer wavelengths of about 150–200 nm can propagate through nitrogen. Scientific instruments can therefore utilize this spectral range by operating in an oxygen-free atmosphere, without the need for costly vacuum chambers. Significant examples include 193 nm photolithography equipment and circular dichroism spectrometers. Technology for VUV instrumentation was driven by solar astronomy for many decades. While optics can be used to remove unwanted visible light that contaminates the VUV, in general, detectors can be limited by their response to non-VUV radiation, the development of "solar-blind" devices has been an important area of research. Wide-gap solid-state devices or vacuum devices with high-cutoff photocathodes can be attractive compared to silicon diodes. Extreme UV is characterized by a transition in the physics of interaction with matter. Wavelengths longer than about 30 nm interact with the outer valence electrons of atoms, while wavelengths shorter than that interact with inner-shell electrons and nuclei.
The long end of the EUV spectrum is set by a prominent He+ spectr
This article refers to a device for ventilation. For the power generation technology, see Solar updraft tower. A solar chimney – referred to as a thermal chimney – is a way of improving the natural ventilation of buildings by using convection of air heated by passive solar energy. A simple description of a solar chimney is that of a vertical shaft utilizing solar energy to enhance the natural stack ventilation through a building; the solar chimney has been in use for centuries in the Middle east and Near East by the Persians, as well as in Europe by the Romans. In its simplest form, the solar chimney consists of a black-painted chimney. During the day solar energy heats the chimney and the air within it, creating an updraft of air in the chimney; the suction created at the chimney's base can be used to cool the building below. In most parts of the world it is easier to harness wind power for such ventilation as with a windcatcher, but on hot windless days a solar chimney can provide ventilation where otherwise there would be none.
There are however a number of solar chimney variations. The basic design elements of a solar chimney are: The solar collector area: This can be located in the top part of the chimney or can include the entire shaft; the orientation, type of glazing and thermal properties of this element are crucial for harnessing and utilizing solar gains. The main ventilation shaft: The location, cross section and the thermal properties of this structure are very important; the inlet and outlet air apertures: The sizes, location as well as aerodynamic aspects of these elements are significant. A principle has been proposed for solar power generation, using a large greenhouse at the base rather than relying on heating the chimney itself. Solar chimneys are painted black; when the air inside the chimney is heated, it rises and pulls cold air out from under the ground via the heat exchange tubes. Solar chimneys called heat chimneys or heat stacks, can be used in architectural settings to decrease the energy used by mechanical systems.
Air conditioning and mechanical ventilation have been for decades the standard method of environmental control in many building types offices, in developed countries. Pollution and reallocating energy supplies have led to a new environmental approach in building design. Innovative technologies along with bioclimatic principles and traditional design strategies are combined to create new and successful design solutions; the solar chimney is one of these concepts explored by scientists as well as designers through research and experimentation. A solar chimney can serve many purposes. Direct gain warms air inside the chimney causing it to rise out the top and drawing air in from the bottom; this drawing of air can be used to ventilate a home or office, to draw air through a geothermal heat exchange, or to ventilate only a specific area such as a composting toilet. Natural ventilation can be created by providing vents in the upper level of a building to allow warm air to rise by convection and escape to the outside.
At the same time cooler air can be drawn in through vents at the lower level. Trees may be planted on that side of the building to provide shade for cooler outside air; this natural ventilation process can be augmented by a solar chimney. The chimney has to be higher than the roof level, has to be constructed on the wall facing the direction of the sun. Absorption of heat from the sun can be increased by using a glazed surface on the side facing the sun. Heat absorbing material can be used on the opposing side; the size of the heat-absorbing surface is more important than the diameter of the chimney. A large surface area allows for more effective heat exchange with the air necessary for heating by solar radiation. Heating of the air within the chimney will enhance convection, hence airflow through the chimney. Openings of the vents in the chimney should face away from the direction of the prevailing wind. To further maximize the cooling effect, the incoming air may be led through underground ducts before it is allowed to enter the building.
The solar chimney can be improved by integrating it with a trombe wall. The added advantage of this design is that the system may be reversed during the cold season, providing solar heating instead. A variation of the solar chimney concept is the solar attic. In a hot sunny climate the attic space is blazingly hot in the summer. In a conventional building this presents a problem as it leads to the need for increased air conditioning. By integrating the attic space with a solar chimney, the hot air in the attic can be put to work, it can help the convection in the chimney. The use of a solar chimney may benefit natural ventilation and passive cooling strategies of buildings thus help reduce energy use, CO2 emissions and pollution in general. Potential benefits regarding natural ventilation and use of solar chimneys are: improved ventilation rates on still, hot days reduced reliance on wind and wind driven ventilation improved control of air flow through a building greater choice of air intake improved air quality and reduced noise levels in urban areas increased night time ventilation rates ventilation of narrow, small spaces with minimal exposure to external elementsPotential benefits regarding passive cooling may include: improved passive cooling during warm season improved night cooling rates enhanced performance of thermal mass improved thermal comfort (improved
Design Build Bluff
Design Build Bluff is a program of The University of Utah's College of Architecture + Planning, where each year, architecture graduate students are immersed in a hands-on opportunity to design and build a full-scale work of architecture in collaboration with the Navajo people. The program derives its name from the town of Bluff, adjacent to the Navajo Nation, in which the campus facility is located. Design Build Bluff projects are a full donation to the client and are noted for being, innovative and award winning designs; the program is collaborating with the Mexican Water Chapter House on more community based projects. The students are empowered “with the practical hard skills needed to test their theories through applied research. With the hope that students will become better, more conscientious, empathetic architects for the benefit of the larger community. DesignBuildBLUFF was founded in 2000 by University of Hank Louis; the program is modeled on a design-build program at Auburn University, known as the Rural Studio, founded by Samuel Mockbee.
In the Rural Studio model, students abandon the comforts of campus and home for a cooperative life, to learn about architecture through action. The design-build paradigm emphasizes experimentation, scale mock-ups, in-process design iterations, consensus-building through ideas and emotions, juxtaposing diametrically opposed cultures. Since its inception Design Build Bluff has expanded to include The University of Colorado Denver in 2010, more evolved from an independent non-profit to being formally housed within the University of Utah. Hank Louis has since passed leadership, in 2013 the program welcomed new director, José Galarza, who came from the Yestermorrow Design/Build School; the program emphasizes the design and construction of homes using "green-build" techniques such as passive solar, rainwater catchment, earthen plaster, rammed earth, straw bale construction, cellulose insulation, Icynene foam, materials salvaged from the landscape of the reservation itself such as a substratum of natural clay, reed from the local riverbed.
Design plans are formatted around donated and recycled materials such as lumber, windows and appliances. Additionally, some of the homes are built from a unique material, FlexCrete, a new concrete block product made with fibrous aggregate from the surrounding soil, produced locally on the Navajo Nation, thereby further reducing the need to import building materials; the projects are completed on a modest cash budget due to grant funding, made possible by the generosity of the local design and construction community. Annual donors such as Big D Construction and 3Form have been involved in the projects for many years. Building sustainable, off-grid homes that have little impact on the environment accomplishes for the Navajo Nation the mission of respecting the landscape while providing adequate housing; as the program includes more community based projects it hopes to reinforce the relationship with the Navajo people, align with community goals, maintain relevance. 2000 - Bandstand Project 2001 - Bend In the River Project 2002 & 2003 - Kunga House 2004 - Rosie Joe House 2005 - Johnson House 2006 - Sweet Caroline House 2007 - Benally House 2008 - ShipShop & BathHouse.
"Sustainable Homes For People Who Need Them"
Druk White Lotus School
The Druk White Lotus School is located in Shey, Ladakh, in northern India, is known locally as the Druk Padma Karpo School. Karpo means Padma means Lotus in the local language Bodhi; the school was started at the request of the people of Ladakh who wanted a school that would help maintain their rich cultural traditions, based on Tibetan Buddhism, while equipping their children for a life in the 21st century. The masterplan and school buildings, designed by architects and engineers from Arup Associates and Ove Arup & Partners, combine local building techniques and materials with leading edge environmental design to make them effective in the extreme climate. In 2012, landscape architects from the School of Architecture and Construction at the University of Greenwich began work on a landscape master plan and garden for the DWLS School; the school offers a broad education in the Ladakhi language and English. Residential blocks allow children from Ladakh's remote areas to attend, a programme of sponsorship ensures that the poorest are not excluded.
It is managed by the Druk Pema Karpo Educational Society and financed with money raised internationally. Druk White Lotus/Padma Karpo school is being built in stages; the Nursery and Infant Courtyard opened in September 2001, the Junior School in November 2004. Middle and Secondary School facilities were built year by year as funds permitted, with the last two secondary school classrooms completed in 2014. Additional facilities for residential students and the school are ongoing; the school was featured in a 2007 episode of the PBS series Design e2, Cisco Systems "Human Network" advertisement as well as the Aamir Khan movie 3 Idiots. The school was damaged in August 2010 when cloudbursts caused flash floods that washed mud and boulders into many school buildings; the Bollywood star Aamir Khan made a special effort to lend a helping hand. Founder The Gyalwang DrukpaPatrons The 14th Dalai Lama The 2nd Thuksey RinpocheHonorary patrons Joanna Lumley OBE FRGS Richard Gere Dowager Countess Cawdor Viscount Cowdray and Viscountess CowdraySupporters The Yardbirds Donovan*Peaks Foundation The International Architecture in Stone Award, 2013: The Emirates Glass LEAF Awards, 2012 for'Best Sustainable Development': ‘Test of Time: Environmental’ Award from the British Council for School Environments, 2012: Design for Asia Grand Award, 2009: Award for ‘Inspiring Design - International’ from the British Council for School Environments, 2009: Australian National Association of Women in Construction, 2005: Sinclair Knight Merz Award for Achievement in Development British Consultants and Construction Bureau - International Expertise Awards, 2003: Large Consultancy Firm of the Year 2003 World Architecture Awards, 2002,: Best Asian Building Best Education Building Best Green Building Tibetan Children's Villages The Druk White Lotus School.
Arup Associates article on the school and its awards. His Holiness the Gyalwang Drukpa, school founder.'A Visionary School Takes Shape in the Himalaya' by the University at Buffalo.'Cisco Systems Human Network' microsite. The Dragon Garden at the Druk White Lotus School
Feces are the solid or semisolid remains of the food that could not be digested in the small intestine. Bacteria in the large intestine further break down the material. Feces contain a small amount of metabolic waste products such as bacterially altered bilirubin, the dead epithelial cells from the lining of the gut. Feces are discharged through cloaca during a process called defecation. Feces can be used as soil conditioner in agriculture, it can be burned and used as a fuel source or dried and used as a construction material. Some medicinal uses have been found. In the case of human feces, fecal transplants or fecal bacteriotherapy are in use. Urine and feces together are called excreta; the distinctive odor of feces is due to bacterial action. Gut flora produces compounds such as indole and thiols, as well as the inorganic gas hydrogen sulfide; these are the same compounds. Consumption of foods prepared with spices may result in the spices being undigested and adding to the odor of feces; the perceived bad odor of feces has been hypothesized to be a deterrent for humans, as consuming or touching it may result in sickness or infection.
Human perception of the odor may be contrasted by a non-human animal's perception of it. Feces are discharged through cloaca during a process called defecation; this process requires pressures that may reach 100 mm Hg in 450 mm Hg in penguins. The forces required to expel the feces are generated through muscular contractions and a build-up of gases inside the gut, prompting the sphincter to relieve the pressure on it and to release the feces. After an animal has digested eaten material, the remains of that material are discharged from its body as waste. Although it is lower in energy than the food from which it is derived, feces may retain a large amount of energy 50% of that of the original food; this means that of all food eaten, a significant amount of energy remains for the decomposers of ecosystems. Many organisms feed on feces, from bacteria to fungi to insects such as dung beetles, who can sense odors from long distances; some may specialize in feces. Feces serve not only as a basic food, but as a supplement to the usual diet of some animals.
This process is known as coprophagia, occurs in various animal species such as young elephants eating the feces of their mothers to gain essential gut flora, or by other animals such as dogs and monkeys. Feces and urine, which reflect ultraviolet light, are important to raptors such as kestrels, who can see the near ultraviolet and thus find their prey by their middens and territorial markers. Seeds may be found in feces. Animals who eat fruit are known as frugivores. An advantage for a plant in having fruit is that animals will eat the fruit and unknowingly disperse the seed in doing so; this mode of seed dispersal is successful, as seeds dispersed around the base of a plant are unlikely to succeed and are subject to heavy predation. Provided the seed can withstand the pathway through the digestive system, it is not only to be far away from the parent plant, but is provided with its own fertilizer. Organisms that subsist on dead organic matter or detritus are known as detritivores, play an important role in ecosystems by recycling organic matter back into a simpler form that plants and other autotrophs may absorb once again.
This cycling of matter is known as the biogeochemical cycle. To maintain nutrients in soil it is therefore important that feces return to the area from which they came, not always the case in human society where food may be transported from rural areas to urban populations and feces disposed of into a river or sea. Depending on the individual and the circumstances, human beings may defecate several times a day, every day, or once every two or three days; the extensive hardening that interrupts this routine for several days or more is called constipation. The appearance of human fecal matter varies according to health, it is semisolid, with a mucus coating. A combination of bile and bilirubin, which comes from dead red blood cells, gives feces the typical brown color. After the meconium, the first stool expelled, a newborn's feces contain only bile, which gives it a yellow-green color. Breast feeding babies expel soft, pale yellowish, not quite malodorous matter. At different times in their life, human beings will expel feces of different textures.
A stool that passes through the intestines will look greenish. The feces of animals are used as fertilizer. Dry animal dung is used as a fuel source in many countries around the world; some animal feces that of camel and cattle, are fuel sources when dried. Animals such as the giant panda and zebra possess gut bacteria capable of producing biofuel; that bacteria, called Brocadia anammoxidans, can create the rocket fuel hydrazine. A coprolite is classified as a trace fossil. In paleontology they give evidence about the diet of an animal, they were first described by William Buckland in 1829. Prior to this they were known as "fossil fir cones" and "bezoar stones", they serve a valuable purpose in paleontology because they provide direct evidence of the predation and diet of extinct organisms. Coprolites may range in size from a few millimetres to more than 60 centimetres. Palaeofeces are ancie