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Podostemum Ceratophyllum
''Podostemum ceratophyllum'', commonly known as the hornleaf riverweed, is a species of submerged aquatic plant in the family Podostemaceae. It is native to eastern North America where it grows on hard bottoms in swiftly flowing rivers and streams and is considered a foundation species. Description The roots are green, fleshy and flattened, spreading finger-like over the surface of the rock to provide anchorage. The stems are closely packed together, being apart. The leaves have basal sheaths and boat-shaped leaf bases which extend into stipules. The petioles are slender and the leaf blades linear. The inflorescences are lateral, each individual flower being bilaterally symmetric. Each flower has two scale-like tepals that are shorter than the ovary, and a further tepal on top of the andropodium, between the two stamens. The ovary is set on a pedicel and orientated obliquely. The fruit is a two-chambered capsule. The actual form of the plant is rather variable, probably influenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
André Michaux
André Michaux, also styled Andrew Michaud, (8 March 174611 October 1802) was a French botanist and explorer. He is most noted for his study of North American flora. In addition Michaux collected specimens in England, Spain, France, and even Persia. His work was part of a larger European effort to gather knowledge about the natural world. Michaux's contributions include ''Histoire des chênes de l'Amérique'' (1801; "The Oaks of North America") and ''Flora Boreali-Americana'' (1803; "The Flora of North America") which continued to be botanical references well into the 19th century. His son, François André Michaux, also became an authoritative botanist. Biography Michaux was born in Satory, part of Versailles, Yvelines, where his father managed farmland on the king's estate. Michaux was trained in the agricultural sciences in anticipation of his one-day assuming his father's duties, and received a basic classical 18th century education, including Latin and some Greek, unt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georgia (U
Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the country in the Caucasus ** Kingdom of Georgia, a medieval kingdom ** Georgia within the Russian Empire ** Democratic Republic of Georgia, established following the Russian Revolution ** Georgian Soviet Socialist Republic, a constituent of the Soviet Union * Related to the US state ** Province of Georgia, one of the thirteen American colonies established by Great Britain in what became the United States ** Georgia in the American Civil War, the State of Georgia within the Confederate States of America. Other places * 359 Georgia, an asteroid * New Georgia, Solomon Islands * South Georgia and the South Sandwich Islands Canada * Georgia Street, in Vancouver, British Columbia, Canada * Strait of Georgia, British Columbia, Canada ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snail
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastropoda that have a coiled shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called '' slugs'', and land snails that have only a very small shell (that they cannot retract into) are often called '' semi-slugs''. Snails have considerable human relevance, including as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewelry. The snail has also had some cultural significance, tending to be associated with lethar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks, annelids, echinoderms and cnidarians. The majority of animal species are invertebrates; one estimate puts the figure at 97%. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata. Invertebrates vary widely in size, from 50 μm (0.002 in) rotifers to the 9–10 m (30–33 ft) colossal squid. Some so-called invertebrates, such as the Tunicata and Cephalochordata, are more closely related to vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy. Etymology The word "invertebrate" comes from the Latin word ''vertebra' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ocean floor), a number of species have parasitic phases, and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds, and puddles, damp moss, or water-filled recesses (phytotelmata) of plants such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators. As with other crustaceans, copepods have a larval form. For copepods, the egg hatches into a nauplius form, with a head and a tail but no true thorax or abdomen. The larva molts several times until it resembles the adult and then, after more molts, achieves adult development. The nauplius form is so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladocera
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrachnidia
Hydrachnidia, also known as "water mites", Hydrachnidiae, Hydracarina or Hydrachnellae, are among the most abundant and diverse groups of benthic arthropods, composed of 6,000 described species from 57 families. As water mites of Africa, Asia, and South America have not been well-studied, the numbers are likely to be far greater. Other taxa of parasitengone mites include species with semi-aquatic habits, but only the Hydracarina are properly subaquatic. Water mites follow the general Parasitengona life cycle: active larva, inactive (calyptostasic) protonymph, active deutonymph, inactive tritonymph and active adult. Usually, larvae are parasites, while deutonymphs and adults are predators. Description Water mites may be brilliant red or orange in colour, unusual among freshwater invertebrates, but they also display more subtle blues, greens and yellows. They are also unusual among mites in some lineages having movable, internalized eye lenses sunk deep within the prosoma rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The Annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbellaria
The Turbellaria are one of the traditional sub-divisions of the phylum Platyhelminthes (flatworms), and include all the sub-groups that are not exclusively parasitic. There are about 4,500 species, which range from to large freshwater forms more than long or terrestrial species like '' Bipalium kewense'' which can reach in length. All the larger forms are flat with ribbon-like or leaf-like shapes, since their lack of respiratory and circulatory systems means that they have to rely on diffusion for internal transport of metabolites. However, many of the smaller forms are round in cross section. Most are predators, and all live in water or in moist terrestrial environments. Most forms reproduce sexually and with few exceptions all are simultaneous hermaphrodites. The Acoelomorpha and the genus '' Xenoturbella'' were formerly included in the Turbellaria, but are no longer regarded as Platyhelminthes. All the exclusively parasitic Platyhelminthes form a monophyletic group N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cnidaria
Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in Fresh water, freshwater and Marine habitats, marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell (biology), cell thick. Cnidarians mostly have two basic body forms: swimming Medusa (biology), medusae and Sessility (motility), sessile polyp (zoology), polyps, both of which are Symmetry (biology)#Radial symmetry, radially symmetrical with mouths surrounded by tentacles that bear cnidocytes. Both forms have a single Body orifice, orifice and body cavity that are used for digestion and respiration (physiology), respiration. Many cnidarian species produce Colony (biology), colonies that are single organisms composed of medusa-like or polyp (z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
