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Dwarf Wedgemussel
The dwarf wedgemussel (''Alasmidonta heterodon'') is an endangered species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. Distribution and conservation status This is a rare species found solely in North America's Atlantic coast streams and rivers of various sizes and moderate current. The dwarf wedge mussel's current range extends from New Hampshire to North Carolina. The dwarf wedge mussel is federally listed as endangered and state-listed as endangered in Connecticut, Massachusetts, Maryland, North Carolina, New Hampshire, New Jersey, New York, Pennsylvania, Virginia, and Vermont. It previously lived in New Brunswick, but it is locally extirpated in Canada since 1968.COSEWIC. 2005. Canadian Species at Risk]. Committee on the Status of Endangered Wildlife in Canada. 64 pp., page 8. The Canadian Species at Risk Act listed the Dwarf Wedge Mussel in the List of Wildlife Species at Risk as being extirpated in Canada. Biotope Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Lea
Isaac; grc, Ἰσαάκ, Isaák; ar, إسحٰق/إسحاق, Isḥāq; am, ይስሐቅ is one of the three patriarchs of the Israelites and an important figure in the Abrahamic religions, including Judaism, Christianity, and Islam. He was the son of Abraham and Sarah, the father of Jacob and Esau, and the grandfather of the twelve tribes of Israel. Isaac's name means "he will laugh", reflecting the laughter, in disbelief, of Abraham and Sarah, when told by God that they would have a child., He is the only patriarch whose name was not changed, and the only one who did not move out of Canaan. According to the narrative, he died aged 180, the longest-lived of the three patriarchs. Etymology The anglicized name "Isaac" is a transliteration of the Hebrew name () which literally means "He laughs/will laugh." Ugaritic texts dating from the 13th century BCE refer to the benevolent smile of the Canaanite deity El. Genesis, however, ascribes the laughter to Isaac's parents, Abraha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virginia
Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond; Virginia Beach is the most-populous city, and Fairfax County is the most-populous political subdivision. The Commonwealth's population was over 8.65million, with 36% of them living in the Baltimore–Washington metropolitan area. The area's history begins with several indigenous groups, including the Powhatan. In 1607, the London Company established the Colony of Virginia as the first permanent English colony in the New World. Virginia's state nickname, the Old Dominion, is a reference to this status. Slave labor and land acquired from displaced native tribes fueled the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johnny Darter
The johnny darter (''Etheostoma nigrum'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to shallow waters throughout North America east of the Rocky Mountains. Etymology The johnny darter's Latin name comes from the Greek root words , meaning to filter, ''stoma'', meaning mouth, and '' nigrum'', meaning black. Geographic distribution The johnny darter is found from Saskatchewan and Colorado to the Atlantic seaboard and from Hudson Bay south to the Gulf Coast drainage systems. They are the most common darter in Minnesota and Ohio.http://www.dnr.state.oh.us/Home/species_a_to_z/SpeciesGuideIndex/johnnydarter/tabid/6664/Default.aspx Description The johnny darter can reach a length of TL though most only reach about . Males weigh a little over 2.0 grams, and the females weigh about 1.6 grams. These small, slender fish have brown to yellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etheostoma Olmstedi
The tessellated darter (''Etheostoma olmstedi'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to Canada and the United States. It was formerly considered a subspecies of the johnny darter, which it greatly resembles in general appearance. Description Both the tessellated darter and johnny darter are rather pale with small X or W shaped markings on the back and upper sides. Both have only a single anal fin spine whereas all other darters in their range have two. Tessellated darters have somewhat sharper snouts than johnny darters, more dorsal soft rays, and more pectoral fin rays. The suborbital sensory canal is complete in most tessellated darters, usually broken into two sections in johnny darters. Their nape is usually naked, and their cheeks are partly to completely scaled. The breast is usually naked and the belly partly scaled. The b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tessellated Darter
The tessellated darter (''Etheostoma olmstedi'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to Canada and the United States. It was formerly considered a subspecies of the johnny darter, which it greatly resembles in general appearance. Description Both the tessellated darter and johnny darter are rather pale with small X or W shaped markings on the back and upper sides. Both have only a single anal fin spine whereas all other darters in their range have two. Tessellated darters have somewhat sharper snouts than johnny darters, more dorsal soft rays, and more pectoral fin rays. The suborbital sensory canal is complete in most tessellated darters, usually broken into two sections in johnny darters. Their nape is usually naked, and their cheeks are partly to completely scaled. The breast is usually naked and the belly partly scaled. The b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glochidium
The glochidium (plural glochidia) is a microscopic larval stage of some freshwater mussels, aquatic bivalve mollusks in the families Unionidae and Margaritiferidae, the river mussels and European freshwater pearl mussels. These larvae are tiny and are typically between 100 and 200 micrometers, or approximately a third of the size of a grain of salt. They can be round or have hooks, attaching to the gills, fins and scales of fish (for example to the gills of a fish host species) for a period before it detaches and falls to the substrate and takes on the typical form of a juvenile mussel. Since a fish is active and free-swimming, this process helps distribute the mussel species to potential areas of habitat that it could not reach any other way. Before the origin of this larval form was understood, it was described as "parasitic worms" on the fish host, although under normal circumstances, glochidia do not harm fish. Overexposure or heavy infections of glochidia may however g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridescent
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfly wings and seashell nacre, and minerals such as opal. It is a kind of structural coloration that is due to wave interference of light in microstructures or thin films. Pearlescence is a related effect where some or most of the reflected light is white. The term pearlescent is used to describe certain paint finishes, usually in the automotive industry, which actually produce iridescent effects. Etymology The word ''iridescence'' is derived in part from the Greek word ἶρις ''îris'' ( gen. ἴριδος ''íridos''), meaning ''rainbow'', and is combined with the Latin suffix ''-escent'', meaning "having a tendency toward". Iris in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacre
Nacre ( , ), also known as mother of pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer; it is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as ''flame structure'' as is found in conch pearls. The outer layer of cultured pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the Haliotidae, the Trochidae and the Turbinidae. Physical characteristics Structure and appearance Nacre is composed of hexagonal platelets of aragonite (a form of calcium carbonate) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (biology)
In biology, a substrate is the surface on which an organism (such as a plant, fungus, or animal) lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants. In biology substrates are often activated by the nanoscopic process of substrate presentation. In agriculture and horticulture * Cellulose substrate * Expanded clay aggregate (LECA) * Rock wool * Potting soil * Soil In animal biotechnology Requirements for animal cell and tissue culture Requirements for animal cell and tissue culture are the same as described for plant cell, tissue and organ culture (In Vitro Culture Techniques: The Biotechnological Principles). Desirable requirements are (i) air conditioning of a room, (ii) hot room with temperature recorder, (iii) microscope r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Extinction
Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a change in the ecology of an area. In recent times, local extinction has sometimes been followed by a replacement of the species taken from other locations; wolf reintroduction is an example of this. The term "local extinction" is highly vernacular. The more proper biological term is ''extirpation''. Discussion Glaciation can lead to local extinction. This was the case during the Pleistocene glaciation event in North America. During this period, most of the native North American species of earthworm were killed in places covered by glaciation. This left them open for colonization by European earthworms brought over in soil from Europe. Species naturally become extirpated from islands over time. The number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Wildlife Species At Risk
The List of Wildlife Species at Risk currently has more than 800 entries for Canadian wild life species considered vulnerable; including 363 classified as endangered species, —190 threatened species, —235 special concern, and 22 extirpated (no longer found in the wild). About 65 percent of Canada’s resident species are considered "Secure". More than 30 wildlife species have become extinct in the wild since the arrival of European settlers. The Government of Canada maintains a list of all plant and animal species, or designatable units (DUs) thereof, federally recognized as special concern, threatened, endangered, extirpated, and extinct in Canada under Schedule I of the Species at Risk Act (SARA). SARA Schedule Species listed on SARA Schedule I receive federal legal protections under the Act, including the protection of individuals, populations, and their habitat from harm. Listing on Schedule I of the act also mandates the formation of a species recovery team and strateg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
