A killifish is any of various oviparous cyprinodontiform fish. Altogether, there are some 1270 different species of killifish, the biggest family being Rivulidae, because of living in ephemeral waters, the eggs of most killifish can survive periods of partial dehydration. Many of the species rely on such a diapause, since the eggs would not survive more than a few weeks if entirely submerged in water, like seeds, the eggs can be sent by mail without water. The adults of species, such as Kryptolebias marmoratus, can additionally survive out of the water for several weeks. Most killies are small fish, from one to two inches, with the largest species growing to just under six inches, the word killifish is of uncertain origin, but is likely to have come from the Dutch kil for a kill. Killifish are found mainly in fresh or brackish waters in the Americas, as far south as Argentina and as far north as southern Ontario. There are species in southern Europe, in much of Africa as far south as KwaZulu-Natal, South Africa, in the Middle East and Asia, killifish are not found in Australia, Antarctica, or northern Europe.
The majority of killifish are found in permanent streams and lakes, such killifish are common in the Americas as well as in Africa and Asia and southern Europe. Some specialized forms live in ponds and flood plains. Such species, known as annuals, live no longer than nine months, a small number of species will shoal while most are territorial to varying degrees. Populations can be dense and territories can shift quickly, especially for species of the extreme shallows, many species exist as passive tribes in small streams where dominant males will defend a territory while allowing females and immature males to pass through the area. In the aquarium, territorial behavior is different for every grouping, in a large enough aquarium, most species can live in groups as long as there are more than three males. Killifish feed primarily on arthropods such as insect larvae, aquatic crustaceans. It is reported by the killifish collector Rudolf Koubek that areas in Gabon where the streams lack killifish are rife with malaria, some species of Orestias from Lake Titicaca are planktonic filter feeders.
Others, such as Cynolebias and Megalebias species and Nothobranchius ocellatus are predatory, the American Flagfish feeds heavily on algae and other plant matter as well as aquatic invertebrates. Nothobranchius furzeri needs much food because it quickly, so when food supplied is inadequate. Some strains have a lifespan as short as several months and can serve as a model for biogerontological studies. The African turquoise killifish is the shortest-living vertebrate that can be bred in captivity, sexual maturation occurs within 3–4 weeks, with fecundity peaking in 8–10 weeks
Mammoth Cave National Park
Mammoth Cave National Park is a U. S. national park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the system under Flint Ridge to the north. The park was established as a park on July 1,1941. It became a World Heritage Site on October 27,1981, the parks 52,830 acres are located primarily in Edmonson County, with small areas extending eastward into Hart County and Barren County. It is centered on the Green River, with a tributary, with 405 miles of surveyed passageways Mammoth Cave is by far the worlds longest known cave system, being over twice as long as the second-longest cave system, Mexicos Sac Actun underwater cave. Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone and it is known to include more than 390 miles of passageway, new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system, the epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges.
It is in underlying massive limestone layers that the human-explorable caves of the region have naturally developed. The limestone layers of the column beneath the Big Clifty, in increasing order of depth below the ridgetops, are the Girkin Formation. Genevieve Limestone, and the St. Louis Limestone, for example, the large Main Cave passage seen on the Historic Tour is located at the bottom of the Girkin and the top of the Ste. Each of the layers of limestone is divided further into named geological units and subunits. One area of research involves correlating the stratigraphy with the cave survey produced by explorers. This makes it possible to produce approximate three-dimensional maps of the contours of the layer boundaries without the necessity for test wells. The upper sandstone caprock is relatively hard for water to penetrate, the sandstone caprock layer has been dissolved and eroded at many locations within the park, such as the Frozen Niagara room. At one valley bottom in the region of the park.
Known as Cedar Sink, the features a small river entering one side. Mammoth Cave is home to the endangered Kentucky cave shrimp, a sightless albino shrimp, the National Park Service offers several cave tours to visitors. Some notable features of the cave, such as Grand Avenue, Frozen Niagara, two tours, lit only by visitor-carried paraffin lamps, are popular alternatives to the electric-lit routes
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can be released to fuel the organisms activities. In most cases, oxygen is released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, such organisms are called photoautotrophs, in plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, in the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate. Using the ATP and NADPH produced by the light-dependent reactions, the compounds are reduced and removed to form further carbohydrates. Cyanobacteria appeared later, the oxygen they produced contributed directly to the oxygenation of the Earth. Today, the rate of energy capture by photosynthesis globally is approximately 130 terawatts.
Photosynthetic organisms convert around 100–115 thousand million tonnes of carbon into biomass per year. Photosynthetic organisms are photoautotrophs, which means that they are able to synthesize food directly from carbon dioxide, not all organisms that use light as a source of energy carry out photosynthesis, photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants and cyanobacteria, photosynthesis releases oxygen and this is called oxygenic photosynthesis and is by far the most common type of photosynthesis used by living organisms. Although there are differences between oxygenic photosynthesis in plants and cyanobacteria, the overall process is quite similar in these organisms. There are varieties of anoxygenic photosynthesis, used mostly by certain types of bacteria. Carbon dioxide is converted into sugars in a process called carbon fixation, photosynthesis provides the energy in the form of free electrons that are used to split carbon from carbon dioxide that is used to fix that carbon once again as carbohydrate.
Carbon fixation is a redox reaction, so photosynthesis supplies the energy that drives both process. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the energy-storage molecules ATP, during the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide. Most organisms that utilize oxygenic photosynthesis use visible light for the light-dependent reactions, some organisms employ even more radical variants of photosynthesis. Some archea use a method that employs a pigment similar to those used for vision in animals. The bacteriorhodopsin changes its configuration in response to sunlight, acting as a proton pump and this produces a proton gradient more directly, which is converted to chemical energy
Typhlichthys subterraneus is a species of fish in the Amblyopsidae family endemic to karst regions of the eastern United States. T. subterraneus is a member of the family Amblyopsidae, and is one of four troglobitic species, the southern cavefish was described by Charles Frédéric Girard in 1859 from a well near Bowling Green, Warren County, Kentucky. Later, Eigenmann in 1905 described both T. osborni and T. wyandotte based on differences in width and eye diameter. Typhlichthys osborni was described from Horse Cave, whereas T. wyandotte was described from a well near Corydon, recently, a well-like entrance into a cave on the property of a car dealership in Corydon was discovered and is believed to represent the type locality. Regardless, this species is considered invalid and was not listed as a locality by Woods. Recent surveys in the vicinity of Corydon have failed to document T. subterraneus, typhlichthys eigenmanni was described as a fourth species in the genus from Camden County, Missouri.
Recently, Parenti proposed that T. eigenmanni Charlton,1933 is a synonym of T. subterraneus. Woods and Inger synonymized all species under T. subterraneus on the basis of lack of any clear geographic pattern in morphological variation and this species is more commonly known as the Southern cavefish. This name is due to the states in which it is found, including Indiana, Kentucky, Missouri, Arkansas. The subterranean waters where the cavefish is found is divided by the Mississippi River and it has been observed that the species lives in solitary habitats and is mostly isolated. Tyhplicthys subterraneus is mostly lentic, but can be found in pools of streams near water tables, the cavefish feeds mostly on aquatic arthropods, such as amphipods and isopods. However, their rates are depressed in order to survive food shortages. The reproductive capabilities of this species is low, with fewer than 50 eggs per female. This provides restrictions on its capabilities for recovering from a minor population decline.
When young are produced, they brood in the gill chamber. Sexual maturity requires approximately two years, and the span is approximately four years. Typhlichthys subterraneus is listed as threatened on the IUCN Red List. Due to environmental threats, there has been a recent decline in geographical span and this is perhaps due to pollution, lowering of the water table, flooding of reservoirs, or cave vandalism
Key Cave National Wildlife Refuge
Key Cave National Wildlife Refuge is a 1,060 acre National Wildlife Refuge located in northwestern Alabama, along the Tennessee River downstream from Florence, Alabama. Additional purchases are under negotiation which will increase the size of the refuge to 1,800 acres, more than 6,000 visitors per year visit the refuge. The facility is unstaffed, but is administered by the Wheeler National Wildlife Refuge in Decatur, two caves, Key Cave and Collier Cave, lie within the refuge, approximately 1.5 miles apart. Both caves are closed to the public, each is on the northern shore of Pickwick Lake on the Tennessee River. The area contains several sinkholes and underground systems, including a 38-acre sinkhole lake. The sinkholes and cave systems provide a source of groundwater for the caves, the refuge is set up to minimize the pollution of this groundwater. The land suffers from severe erosion due to the farming in the area. A restoration of the land to native warm season grasses and mixed hardwoods is underway in order to protect the cave groundwater area, approximately 338 acres of the land is used for corn and soybean production under a Cooperative Farm Agreement.
Fields of warm season grasses such as big bluestem, little bluestem, sideoats grama, switchgrass,122 acres of hardwood forest has been planted to help control the erosion. The land of the Key Cave NWR area has historically used for agricultural purposes. The area receives its name from William Key, who owned the land the refuge now contains as well as a house on nearby private property. A slave cemetery called Key Cemetery is located on the refuge, the Key Cave and Collier Cave share the same aquifer system which was being polluted as a result of the farming operations. In 1992, the Monsanto Company sold the land in the highest hazard risk area to The Conservation Fund and this land was sold to the U. S. Fish and Wildlife Service which established the Key Cave NWR on January 3,1997. Key Cave is a habitat for the endangered Alabama cavefish. Only nine specimens are known to exist, the refuge provides protection for approximately 40,000 endangered gray bats. The cave is home to two species of endangered crayfish, Phantom cave crayfish and Cambarus jonesi.
Key Cave NWR manages several bird species including grasshopper sparrows, northern harriers, short-eared owls, loggerhead shrikes, the refuge has 2.5 miles of trails for hiking and cycling. Key Cave is not open to the public, but nearby viewing platforms facilitate the viewing of the bats during the summer and this is the #9 site on the North Alabama Birding Trail
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence and other forms of luminescence, many materials selectively absorb certain wavelengths of light. Materials that humans have chosen and developed for use as pigments usually have properties that make them ideal for coloring other materials. A pigment must have a high tinting strength relative to the materials it colors and it must be stable in solid form at ambient temperatures. For industrial applications, as well as in the arts, pigments that are not permanent are called fugitive. Fugitive pigments fade over time, or with exposure to light, pigments are used for coloring paint, plastic, cosmetics and other materials. Most pigments used in manufacturing and the arts are dry colorants. This powder is added to a binder, a neutral or colorless material that suspends the pigment. A distinction is made between a pigment, which is insoluble in its vehicle, and a dye, which either is itself a liquid or is soluble in its vehicle. A colorant can act as either a pigment or a dye depending on the vehicle involved, in some cases, a pigment can be manufactured from a dye by precipitating a soluble dye with a metallic salt.
The resulting pigment is called a lake pigment, the term biological pigment is used for all colored substances independent of their solubility. In 2006, around 7.4 million tons of inorganic, asia has the highest rate on a quantity basis followed by Europe and North America. By 2020, revenues will have risen to approx, the global demand on pigments was roughly US$20.5 billion in 2009, around 1. 5-2% up from the previous year. It is predicted to increase in a growth rate in the coming years. The worldwide sales are said to increase up to US$24.5 billion in 2015, pigments appear the colors they are because they selectively reflect and absorb certain wavelengths of visible light. White light is an equal mixture of the entire spectrum of visible light with a wavelength in a range from about 375 or 400 nanometers to about 760 or 780 nm. When this light encounters a pigment, parts of the spectrum are absorbed by the molecules or ions of the pigment, in organic pigments such as diazo or phthalocyanine compounds the light is absorbed by the conjugated systems of double bonds in the molecule.
Some of the inorganic pigments such as vermilion or cadmium yellow absorb light by transferring an electron from the ion to the positive ion
Fins are usually the most distinctive features of a fish. Apart from the tail or caudal fin, fish fins have no connection with the spine and are supported only by muscles. Their principal function is to help the fish swim, 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, 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 a group called Osteichthyes. They have skeletons made of bone, and can be contrasted with cartilaginous fishes which have made of cartilage. Bony fishes are divided into ray-finned and lobe-finned fish, most fish are ray-finned, an extremely 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 spines and rays called lepidotrichia and they typically have swim bladders, which allows the fish to create a neutral balance between sinking and floating without having to use its fins. However, these are absent in species, and have developed into primitive lungs in the lungfishes. 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 and these fins evolved into legs of the first tetrapod land vertebrates, amphibians. They possess two dorsal fins with separate bases, as opposed to the dorsal fin of ray-finned fish. The coelacanth is another lobe-finned fish which is still extant and it is thought to have evolved into roughly 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 commonly take advantage of up or downwellings of the current and drift. They use their fins to stabilize their movement through the water
A tooth is a hard, calcified structure found in the jaws of many vertebrates and used to break down food. Some animals, particularly carnivores, use teeth for hunting or for defensive purposes, the roots of teeth are covered by gums. Teeth are not made of bone, but rather of tissues of varying density. The cellular tissues that ultimately become teeth originate from the germ layer. The general structure of teeth is similar across the vertebrates, although there is variation in their form. The teeth of mammals have deep roots, and this pattern is found in some fish. In most teleost fish, the teeth are attached to the surface of the bone. In cartilaginous fish, such as sharks, the teeth are attached by tough ligaments to the hoops of cartilage that form the jaw, some animals develop only one set of teeth while others develop many sets. Sharks, for example, grow a new set of every two weeks to replace worn teeth. Rodent incisors grow and wear away continually through gnawing, which helps maintain relatively constant length, the industry of the beaver is due in part to this qualification.
Many rodents such as voles and guinea pigs, but not mice, Teeth are not always attached to the jaw, as they are in mammals. In many reptiles and fish, teeth are attached to the palate or to the floor of the mouth, some teleosts even have teeth in the pharynx. While not true teeth in the sense, the dermal denticles of sharks are almost identical in structure and are likely to have the same evolutionary origin. Though modern teeth-like structures with dentine and enamel have been found in late conodonts, living amphibians typically have small teeth, or none at all, since they commonly feed only on soft foods. In reptiles, teeth are simple and conical in shape. The pattern of incisors, canines and molars is found only in mammals, the numbers of these types of teeth vary greatly between species, zoologists use a standardised dental formula to describe the precise pattern in any given group. The genes governing tooth development in mammals are homologous to these involved in the development of fish scales, Teeth are among the most distinctive features of mammal species.
Paleontologists use teeth to identify species and determine their relationships
Cavefish or cave fish, known as hypogean fish, is a generic term for freshwater fish adapted to life in caves. Being aquatic, they are a part of the group known as stygofauna. The approximately 170 species of cavefish are found in all continents, although widespread as a group, many cavefish species have very small ranges and are seriously threatened. Cavefish are members of a range of families and do not form a monophyletic group. Typical adaptions found in cavefish are reduced eyes and pigmentation, many aboveground fish may enter caves on occasion, but obligate cavefish are extremophiles with a number of unusual adaptions known as troglomorphism. In five species, the Mexican tetra, shortfin molly, Oman garra, Aspidoras albater and Pterocryptis bucccata, living in darkness and eyes are useless and typically reduced in cavefish. Other examples are a loss of scales, swim bladder and behaviors such as types of display. The loss can be complete or only partial, for example resulting in small eyes, in some cases, blind cavefish may still be able to see, juvenile Mexican tetras of the cave form are able to sense light via certain cells in the pineal gland.
In the most extreme cases, the lack of light has changed the rhythm of the cavefish. In the Mexican tetra of the form and in Phreatichthys andruzzii the circadian rhythm lasts 30 hours and 47 hours. This may help them to save energy, without sight, other senses are used and these may be enhanced. Examples include the line for sensing vibrations, electroreception. Cavefish are quite small with few species surpassing 15 cm in length, at up to 40 cm, the blind cave eel is the longest known cavefish. Some deep sea and deep river fish have similar to the cavefish, including reduced eyes. Although the approximately 170 obligate cavefish species are found in most continents, there are strong geographic patterns, cavefish are strongly linked to regions with karst, which commonly result in underground sinkholes and subterranean rivers. With almost 100 species, by far the greatest diversity is in Asia, in contrast, only 9 species are known from Africa and 5 from Oceania. Europe has stygofauna, and in 2017 a cave loach was discovered by divers in a cave labyrinth called the Danube-Aach System in southern Germany.
On a country level, China has the greatest diversity, followed by Brazil, Mexico, United States of America, no other country has more than 4 cavefish species
A swamp is a wetland that is forested. Many swamps occur along rivers where they are critically dependent upon natural water level fluctuations. Other swamps occur on the shores of large lakes, some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation. The two main types of swamp are true or swamp forests and transitional or shrub swamps, in the boreal regions of Canada, the word swamp is colloquially used for what is more correctly termed a bog or muskeg. The water of a swamp may be water, brackish water or seawater. Some of the worlds largest swamps are found along rivers such as the Amazon, the Mississippi. Swamps are characterized by slow-moving to stagnant waters and they are usually associated with adjacent rivers or lakes. Swamps are features of areas with very low topographic relief, humans have drained swamps to provide additional land for agriculture and to reduce the threat of diseases borne by swamp insects and similar animals.
Many swamps have undergone intensive logging, requiring the construction of drainage ditches and these ditches and canals contributed to drainage and, along the coast, allowed salt water to intrude, converting swamps to marsh or even to open water. Large areas of swamp were therefore lost or degraded, louisiana provides a classic example of wetland loss from these combined factors. Europe has probably lost nearly half its wetlands, New Zealand lost 90 percent of its wetlands over a period of 150 years. Ecologists recognise that swamps provide valuable ecological services including flood control, fish production, water purification, carbon storage, in many parts of the world authorities protect swamps. In parts of Europe and North America, swamp restoration projects are becoming widespread, often the simplest steps to restoring swamps involve plugging drainage ditches and removing levees. Swamps and other wetlands have traditionally held a very low property value compared to fields and they have a reputation for being unproductive land that cannot easily be utilized for human activities, other than perhaps hunting and trapping.
Farmers, for example, typically drained swamps next to their fields so as to more land usable for planting crops. Many societies now realize that swamps are important to providing fresh water and oxygen to all life. Indeed, floodplain swamps are important in fish production. Government environmental agencies are taking steps to protect and preserve swamps, in Europe, major effort is being invested in the restoration of swamp forests along rivers