|
Axia (flatworm)
Macrostomidaevan Beneden, E. 1870. Étude zoologique et anatomique du genre ''Macrostomum'' comprenant la description de deux especes nouvelles. Bulletin de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique 30:116-133, one plate. is a family of small basal free-living flatworms, and are found in marine, brackish, and freshwater environments. There are currently about 180 named species in this family.Tyler, S., Schilling, S., Hooge, M., and Bush L. F. (comp.) (2006-2009) Turbellarian taxonomic database. Version 1.5 Description Species of the family Macrostomidae are small (~0.5 to 5 mm in length) and generally highly transparent microturbellarians. They are usually round in cross section, and with only the largest forms being dorso-ventrally flattened. They are distinguished from related animals by the possession of a simple pharynx and intestine, a single pair of lateral nerve cords, and by the absence of a statocyst. Ecology and distribution Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. fresh water, Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthos
Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.Benthos from the Census of Antarctic Marine Life website This community lives in or near marine or freshwater sedimentary environments, from tidal pools along the , out to the continental shelf, and then down to the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meiobenthos
Meiobenthos, also called meiofauna, are small benthic invertebrates that live in marine or freshwater environments, or both. The term ''meiofauna'' loosely defines a group of organisms by their sizelarger than microfauna but smaller than macrofaunarather than by their taxonomy. This fauna includes both animals that turn into macrofauna later in life, and those small enough to belong to the meiobenthos their entire life. In marine environments there can be thousands of individuals in 10 cubic centimeters of sediment, and counts animals like nematodes, copepods, rotifers, tardigrades and ostracods, but protists like ciliates and foraminifers within the size range of the meiobenthos are also often included. In practice, the term usually includes organisms that can pass through a 1 mm mesh but are retained by a 45 μm mesh, though exact dimensions may vary. Whether an organism will pass through a 1 mm mesh also depends upon whether it is alive or dead at the time o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statocyst
The statocyst is a balance sensory receptor present in some aquatic invertebrates, including bivalves, cnidarians, ctenophorans, echinoderms, cephalopods, crustaceans, and gastropods, A similar structure is also found in '' Xenoturbella''. The statocyst consists of a sac-like structure containing a mineralised mass (statolith) and numerous innervated sensory hairs ( setae). The statolith's inertia causes it to push against the setae when the animal accelerates. Deflection of setae by the statolith in response to gravity activates neurons, providing feedback to the animal on change in orientation and allowing balance to be maintained. In other words, the statolith shifts as the animal moves. Any movement large enough to throw the organism off balance causes the statolith to brush against tiny bristles which in turn send a message to the brain to correct its balance. It may have been present in the common ancestor of cnidarians and bilaterians. Hearing In cephalopods like s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharynx
The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food to the esophagus and air to the larynx. The flap of cartilage called the epiglottis stops food from entering the larynx. In humans, the pharynx is part of the Digestion, digestive system and the conducting zone of the respiratory system. (The conducting zone—which also includes the nostrils of the Human nose, nose, the larynx, trachea, bronchus, bronchi, and bronchioles—filters, warms, and moistens air and conducts it into the lungs). The human pharynx is conventionally divided into three sections: the nasopharynx, oropharynx, and laryngopharynx (hypopharynx). In humans, two sets of pharyngeal muscles form the pharynx and determine the shape of its lumen (anatomy), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psammomacrostomum
Macrostomidaevan Beneden, E. 1870. Étude zoologique et anatomique du genre ''Macrostomum'' comprenant la description de deux especes nouvelles. Bulletin de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique 30:116-133, one plate. is a family of small basal free-living flatworms, and are found in marine, brackish, and freshwater environments. There are currently about 180 named species in this family.Tyler, S., Schilling, S., Hooge, M., and Bush L. F. (comp.) (2006-2009) Turbellarian taxonomic database. Version 1.5 Description Species of the family Macrostomidae are small (~0.5 to 5 mm in length) and generally highly transparent microturbellarians. They are usually round in cross section, and with only the largest forms being dorso-ventrally flattened. They are distinguished from related animals by the possession of a simple pharynx and intestine, a single pair of lateral nerve cords, and by the absence of a statocyst. Ecology and distribution Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
