Stilt is a common name for several species of birds in the family Recurvirostridae, which includes those known as avocets. They are found in saline wetlands in warm or hot climates, they have long legs, hence the group name, long thin bills. Stilts feed on aquatic insects and other small creatures and nest on the ground surface in loose colonies. Most sources recognize 6 species in 2 genera, although the white-backed and Hawaiian stilts are considered subspecies of the black-necked stilt; the genus Charadrius was introduced by the French zoologist Mathurin Jacques Brisson in 1760 with the black-winged stilt as the type species. The generic name Himantopus comes from the Ancient Greek meaning "strap-leg"; the genus Himantopus contains five species: Black-winged stilt, Himantopus himantopus White-backed stilt, Himantopus melanurus Pied stilt, Himantopus leucocephalus Black-necked stilt, Himantopus mexicanus Hawaiian stilt or aeʻo, Himantopus mexicanus knudseni Black stilt, Himantopus novaezelandiaeThe genus Cladorhynchus is monotypic and contains a single species: Banded stilt, Cladorhynchus leucocephalusA fossil stilt has been described by Bickart, 1990, as Himantopus olsoni, based on remains recovered in the Late Miocene Big Sandy Formation of Wickieup, United States.
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Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between the elements above and below in the periodic table and tellurium, has similarities to arsenic, it occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the discovered tellurium. Selenium is found in metal sulfide ores, where it replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most during production. Minerals that are pure selenide or selenate compounds are rare; the chief commercial uses for selenium today are pigments. Selenium is used in photocells. Applications in electronics, once important, have been replaced with silicon semiconductor devices. Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot. Selenium salts are toxic in large amounts, but trace amounts are necessary for cellular function in many organisms, including all animals.
Selenium is an ingredient in many multivitamins and other dietary supplements, including infant formula. It is a component of thioredoxin reductase, it is found in three deiodinase enzymes, which convert one thyroid hormone to another. Selenium requirements in plants differ by species, with some plants requiring large amounts and others requiring none. Selenium forms several allotropes that interconvert with temperature changes, depending somewhat on the rate of temperature change; when prepared in chemical reactions, selenium is an amorphous, brick-red powder. When melted, it forms the black, vitreous form sold commercially as beads; the structure of black selenium is irregular and complex and consists of polymeric rings with up to 1000 atoms per ring. Black Se is a brittle, lustrous solid, soluble in CS2. Upon heating, it softens at 50 °C and converts to gray selenium at 180 °C; the red α, β, γ forms are produced from solutions of black selenium by varying the evaporation rate of the solvent. They all have low, monoclinic crystal symmetries and contain nearly identical puckered Se8 rings with different arrangements, as in sulfur.
The packing is most dense in the α form. In the Se8 rings, the Se-Se distance is 233.5 pm and Se-Se-Se angle is 105.7°. Other selenium allotropes may contain Se7 rings; the most stable and dense form of selenium is gray and has a hexagonal crystal lattice consisting of helical polymeric chains, where the Se-Se distance is 237.3 pm and Se-Se-Se angle is 130.1°. The minimum distance between chains is 343.6 pm. Gray Se is formed by mild heating of other allotropes, by slow cooling of molten Se, or by condensing Se vapor just below the melting point. Whereas other Se forms are insulators, gray Se is a semiconductor showing appreciable photoconductivity. Unlike the other allotropes, it is insoluble in CS2, it is not attacked by nonoxidizing acids. With strong reducing agents, it forms polyselenides. Selenium does not exhibit the changes in viscosity that sulfur undergoes when heated. Owing to its use as a photoconductor in flat-panel x-ray detectors, the optical properties of amorphous selenium thin films have been the subject of intense research.
Selenium has seven occurring isotopes. Five of these, 74Se, 76Se, 77Se, 78Se, 80Se, are stable, with 80Se being the most abundant. Occurring is the long-lived primordial radionuclide 82Se, with a half-life of 9.2×1019 years. The non-primordial radioisotope 79Se occurs in minute quantities in uranium ores as a product of nuclear fission. Selenium has numerous unstable synthetic isotopes ranging from 64Se to 95Se. Isotopes lighter than the stable isotopes undergo beta plus decay to isotopes of arsenic, isotopes heavier than the stable isotopes undergo beta minus decay to isotopes of bromine, with some minor neutron emission branches in the heaviest known isotopes. Selenium compounds exist in the oxidation states −2, +2, +4, +6. Selenium forms two oxides: selenium dioxide and selenium trioxide. Selenium dioxide is formed by the reaction of elemental selenium with oxygen: Se8 + 8 O2 → 8 SeO2 It is a polymeric solid that forms monomeric SeO2 molecules in the gas phase, it dissolves in water to form selenous acid, H2SeO3.
Selenous acid can be made directly by oxidizing elemental selenium with nitric acid: 3 Se + 4 HNO3 + H2O → 3 H2SeO3 + 4 NOUnlike sulfur, which forms a stable trioxide, selenium trioxide is thermodynamically unstable and decomposes to the dioxide above 185 °C: 2 SeO3 → 2 SeO2 + O2 Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate and sulfur trioxide. Salts of selenous acid are called selenites; these include sodium selenite. Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide: H2SeO3 + 2 H2S → SeS2 + 3 H2OSelenium disulfide consists of 8-membered rings, it has an approximate composition of SeS2, with individual rings varying in composition, such as Se4S4 and Se2S6. Selenium disulfide has been used in shampoo
Wikispecies is a wiki-based online project supported by the Wikimedia Foundation. Its aim is to create a comprehensive free content catalogue of all species. Jimmy Wales stated that editors are not required to fax in their degrees, but that submissions will have to pass muster with a technical audience. Wikispecies is available under the GNU Free Documentation License and CC BY-SA 3.0. Started in September 2004, with biologists across the world invited to contribute, the project had grown a framework encompassing the Linnaean taxonomy with links to Wikipedia articles on individual species by April 2005. Benedikt Mandl co-ordinated the efforts of several people who are interested in getting involved with the project and contacted potential supporters in early summer 2004. Databases were evaluated and the administrators contacted, some of them have agreed on providing their data for Wikispecies. Mandl defined two major tasks: Figure out how the contents of the data base would need to be presented—by asking experts, potential non-professional users and comparing that with existing databases Figure out how to do the software, which hardware is required and how to cover the costs—by asking experts, looking for fellow volunteers and potential sponsorsAdvantages and disadvantages were discussed by the wikimedia-I mailing list.
The board of directors of the Wikimedia Foundation voted by 4 to 0 in favor of the establishment of a Wikispecies. The project is hosted at species.wikimedia.org. It was merged to a sister project of Wikimedia Foundation on September 14, 2004. On October 10, 2006, the project exceeded 75,000 articles. On May 20, 2007, the project exceeded 100,000 articles with a total of 5,495 registered users. On September 8, 2008, the project exceeded 150,000 articles with a total of 9,224 registered users. On October 23, 2011, the project reached 300,000 articles. On June 16, 2014, the project reached 400,000 articles. On January 7, 2017, the project reached 500,000 articles. On October 30, 2018, the project reached 600,000 articles, a total of 1.12 million pages. Wikispecies comprises taxon pages, additionally pages about synonyms, taxon authorities, taxonomical publications, institutions or repositories holding type specimen. Wikispecies asks users to use images from Wikimedia Commons. Wikispecies does not allow the use of content.
All Species Foundation Catalogue of Life Encyclopedia of Life Tree of Life Web Project List of online encyclopedias The Plant List Wikispecies, The free species directory that anyone can edit Species Community Portal The Wikispecies Charter, written by Wales
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
Birds known as Aves, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, a strong yet lightweight skeleton. Birds range in size from the 5 cm bee hummingbird to the 2.75 m ostrich. They rank as the world's most numerically-successful class of tetrapods, with ten thousand living species, more than half of these being passerines, sometimes known as perching birds. Birds have wings which are less developed depending on the species. Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in flightless birds, including ratites and diverse endemic island species of birds; the digestive and respiratory systems of birds are uniquely adapted for flight. Some bird species of aquatic environments seabirds and some waterbirds, have further evolved for swimming; the fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier feathered dinosaurs within the theropod group, which are traditionally placed within the saurischian dinosaurs.
The closest living relatives of birds are the crocodilians. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period, around 170 million years ago. Many of these early "stem-birds", such as Archaeopteryx, were not yet capable of powered flight, many retained primitive characteristics like toothy jaws in place of beaks, long bony tails. DNA-based evidence finds that birds diversified around the time of the Cretaceous–Palaeogene extinction event 66 million years ago, which killed off the pterosaurs and all the non-avian dinosaur lineages, but birds those in the southern continents, survived this event and migrated to other parts of the world while diversifying during periods of global cooling. This makes them the sole surviving dinosaurs according to cladistics; some birds corvids and parrots, are among the most intelligent animals. Many species annually migrate great distances. Birds are social, communicating with visual signals and bird songs, participating in such social behaviours as cooperative breeding and hunting and mobbing of predators.
The vast majority of bird species are monogamous for one breeding season at a time, sometimes for years, but for life. Other species have breeding systems that are polygynous or polyandrous. Birds produce offspring by laying eggs, they are laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching; some birds, such as hens, lay eggs when not fertilised, though unfertilised eggs do not produce offspring. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs and feathers. Songbirds and other species are popular as pets. Guano is harvested for use as a fertiliser. Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them.
Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae. Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system in use. Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda. Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria. During the late 1990s, Aves was most defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica. However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, is used by many scientists including adherents of the Phylocode system. Gauthier defined Aves to include only the crown group of the set of modern birds; this was done by excluding most groups known only from fossils, assigning them, instead, to the Avialae, in part to avoid the uncertainties about the placement of Archaeopteryx in relation to animals traditionally thought of as theropod dinosaurs.
Gauthier identified four different definitions for the same biological name "Aves", a problem. Gauthier proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below, he assigned other names to the other groups. Aves can mean all archosaurs closer to birds than to crocodiles Aves can mean those advanced archosaurs with feathers Aves can mean those feathered dinosaurs that fly Aves can mean the last common ancestor of all the living birds and all of its descendants (a "c
John James Audubon
John James Audubon was an American ornithologist and painter. He was notable for his extensive studies documenting all types of American birds and for his detailed illustrations that depicted the birds in their natural habitats, his major work, a color-plate book entitled The Birds of America, is considered one of the finest ornithological works completed. Audubon identified 25 new species. Audubon was born in Les Cayes in the French colony of Saint-Domingue on his father's sugarcane plantation, he was the son of Lieutenant Jean Audubon, a French naval officer from the south of Brittany, his mistress Jeanne Rabine, a 27-year-old chambermaid from Les Touches, Brittany. They named the boy Jean Rabin. Another 1887 biographer has stated, his mother died when the boy was a few months old, as she had suffered from tropical disease since arriving on the island. His father had an unknown number of mixed-race children, some by his mulatto housekeeper, Catherine "Sanitte" Bouffard. Following Jeanne Rabin's death, Jean Audubon renewed his relationship with Sanitte Bouffard and had a daughter by her, named Muguet.
Bouffard took care of the infant boy Jean. The senior Audubon had commanded ships. During the American Revolution, he had been imprisoned by Britain. After his release, he helped the American cause, he had long worked to secure his family's future with real estate. Due to slave unrest in the Caribbean, in 1789 he sold part of his plantation in Saint-Domingue and purchased a 284-acre farm called Mill Grove, 20 miles from Philadelphia, to diversify his investments. Increasing tension in Saint-Domingue between the colonists and the African slaves, who outnumbered them, convinced Jean Audubon to return to France, where he became a member of the Republican Guard. In 1791 he arranged for his natural children and Muguet, who were majority-white in ancestry, to be transported and delivered to him in France; the children were raised in Couëron, near Nantes, France, by Audubon and his French wife, Anne Moynet Audubon, whom he had married years before his time in Saint-Domingue. In 1794 they formally adopted both his natural children to regularize their legal status in France.
They renamed the girl Rose. When Audubon, at age 18, boarded ship in 1803 to immigrate to the United States, he changed his name to an anglicized form: John James Audubon. From his earliest days, Audubon had an affinity for birds. "I felt an intimacy with them... bordering on frenzy must accompany my steps through life." His father encouraged his interest in nature: He would point out the elegant movement of the birds, the beauty and softness of their plumage. He called my attention to their show of pleasure or sense of danger, their perfect forms and splendid attire, he would return with the seasons. In France during the chaotic years of the French Revolution and its aftermath, the younger Audubon grew up to be a handsome and gregarious man, he played flute and violin, learned to ride and dance. A great walker, he loved roaming in the woods returning with natural curiosities, including birds' eggs and nests, of which he made crude drawings, his father planned to make a seaman of his son. At twelve, Audubon became a cabin boy.
He found out that he was susceptible to seasickness and not fond of mathematics or navigation. After failing the officer's qualification test, Audubon ended his incipient naval career, he was exploring the fields again, focusing on birds. In 1803, his father obtained a false passport so that Audubon could go to the United States to avoid conscription in the Napoleonic Wars. Jean Audubon and Claude Rozier arranged a business partnership for their sons to pursue in Pennsylvania, it was based on Claude Rozier's buying half of Jean Audubon's share of a plantation in Haiti, lending money to the partnership as secured by half interest in lead mining at Audubon's property of Mill Grove. Audubon caught yellow fever upon arrival in New York City; the ship's captain placed him in a boarding house run by Quaker women. They nursed Audubon to recovery and taught him English, including the Quaker form of using "thee" and "thou", otherwise archaic, he traveled with the family's Quaker lawyer to the Audubon family farm Mill Grove.
The 284-acre homestead is located on the Perkiomen Creek a few miles from Valley Forge. Audubon lived with the tenants in the two-story stone house, in an area that he considered a paradise. "Hunting, fishing and music occupied my every moment. Studying his surroundings, Audubon learned the ornithologist's rule, which he wrote down as, "The nature of the place—whether high or low, moist or dry, whether sloping north or south, or bearing tall trees or low shrubs—generally gives hint as to its inhabitants." His father hoped that the lead mines on the property could be commercially developed, as lead was an essential component of bullets. This could provide his son with a profitable occupation. At Mill Grove, Audubon met the owner of the nearby estate Fatland Ford, William Bakewell, his daughter Lucy, he was married to Lucy five years later. The two young people shared many common interests, early on began to spend time together, exploring the natural world around them. Audubon set about to study American birds, determined to illustrate his findings in a more realist
Palo Alto Baylands Nature Preserve
The Palo Alto Baylands Nature Preserve, known as the Baylands Nature Preserve, is the largest tract of undisturbed marshland remaining in the San Francisco Bay. Fifteen miles of multi-use trails provide access to a unique mixture of tidal and fresh water habitats; the preserve encompasses 1,940 acres in both Palo Alto and East Palo Alto, is owned by the city of Palo Alto, United States. It is an important habitat for migratory shorebirds and is considered one of the best birdwatching spots on the West Coast; the Palo Alto Baylands is located at 37.459608°N 122.106412°W / 37.459608. The preserve consists of the former Yacht Harbor area, the Palo Alto Airport, the Municipal Golf Course, the Duck Pond and public picnic area, the Baylands Athletic Center, the Sailing Station, the Lucy Evans Baylands Nature Interpretive Center, the Harriet Mundy Marsh and the Palo Alto Flood Basin; the flood basin is bordered by Adobe Creek and Matadero Creek and is maintained a couple feet below sea level in order to serve as a catchment basin in case of flooding in lower Palo Alto.
At the northwest edge the Baylands extend past San Francisquito Creek, although the creek used to flow into the Bay at the site of the former Yacht Club. In the late 1920s levees were constructed to re-route San Francisquito Creek away from its former mouth, to a sharp north turn for about half a mile to the northeast, before exiting to the Bay. Dredging of the former Yacht Club produced landfill for the filling of marshlands to construct the Palo Alto Airport and Municipal Golf Course. By 2004, filled areas such as the Palo Alto golf course and the Palo Alto Airport had reduced the tidal marsh to 352 acres; the Byxbee Park Hills area of Baylands was named for John Fletcher Byxbee Jr. Palo Alto City Engineer from 1906 to 1941. Byxbee was a member of the first graduating class of Palo Alto High School. At Stanford University he studied under C. D. Marx, founder of the City of Palo Alto utilities system, graduated with a B. A. in Civil Engineering with the class of 1902. At first named Assistant City Engineer, he became City Engineer in 1906.
Lucy Evans taught at Mayfield School for 23 years. She fought for the preservation of the Baylands, her determination earned her the appellation "Baylands Lucy." She died in 1978. The Baylands Nature Interpretive Center was rededicated to her memory in December 1978; the Harriet Mundy Marsh extends from Lucy Evans Nature Interpretive Center to Sand Point and was dedicated on October 23, 1982, honoring Harriet Mundy who circulated a petition which resulted in the City Council stopping development of a $30 million private proposal to develop the Palo Alto Baylands for commercial and industrial use. The Byxbee Park Hills area of Baylands was named for John Fletcher Byxbee Jr. Palo Alto City Engineer from 1906 to 1941; the Emily Renzel Wetlands restoration project was completed in 1992, utilizing a $1,000,000 grant from the California Coastal Conservancy to enhance the salt marsh portion of wetlands with bay water, creating a new 15-acre fresh water pond. The freshwater pond uses pumped reclaimed water from the nearby Palo Alto Regional Water Quality Control Plant and was named for former City Councilmember Emily Renzel for her tireless work over 20 years to preserve and protect Palo Alto's Baylands.
The Baylands are home to numerous species of plants and animals including the endangered Ridgway's Rail and salt marsh harvest mouse. Several gray fox breeding pairs inhabit the Baylands where they are safe from large predators like puma; the preserve contains 15 miles of multi-use trails and includes the Lucy Evans Baylands Nature Interpretive Center, the Palo Alto Duck Pond, baseball and softball fields at the Baylands Athletic Center. The Lucy Evans Baylands Nature Interpretive Center is built on pilings at the edge of the salt marsh. A plank walk leads a quarter-mile across the marsh to open water and a panoramic view of San Francisco Bay; the interpretive center was renovated in 2017 and the boardwalk is scheduled for renovation in late 2028. San Francisquito Creek Matadero Creek Adobe Creek Official website Map of the Palo Alto Baylands Trailer for Palo Alto Baylands Gray Fox Documentary by Greg Kerekes and Bill Leikam