|
Bipalium Rugiantrum
''Bipalium'' is a genus of large predatory land planarians. They are often loosely called "hammerhead worms" or "broadhead planarians" because of the distinctive shape of their head region. Land planarians are unique in that they possess a "creeping sole", a highly ciliated region on the ventral epidermis that helps them to creep over the substrate. Native to Asia, several species are invasive to the United States, Canada, and Europe. Some studies have begun the investigation of the evolutionary ecology of these invasive planarians. Etymology The name ''Bipalium'' comes from Latin ''bi-'', "two" + ''pala'', "shovel" or "spade", because species in this genus resemble a pickaxe. Description The genus ''Bipalium'' was initially defined by Stimpson to include land planarians with the head broadened, forming a head plate. Later, in 1899, Ludwig von Graff divided it into three genera according to the shape of the head: #''Bipalium'': with a well-developed head plate, much broad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Stimpson
William Stimpson (February 14, 1832 – May 26, 1872) was an American scientist. He was interested particularly in marine biology. Stimpson became an important early contributor to the work of the Smithsonian Institution and later, director of the Chicago Academy of Sciences. Biography Stimpson was born in Boston, Massachusetts to Herbert Hathorne Stimpson and Mary Ann Devereau Brewer. The Stimpsons were of the colonial stock of Massachusetts, the earliest known member of the family being James Stimpson, who was married in 1661, in Milton. His mother died at an early age. William Stimpson's father was an ingenious inventor, and a leading merchant of Boston in the mid decades of the nineteenth century, trading as "H. & F. Stimpson, stoves and furnaces, corner of Congress and Water Streets. It was he who invented the "Stimpson range", the first sheet-iron Kitchen stove, cooking stove, famous in its day throughout New England. He also made Rifle#19th century, improvements in rifl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthworm
An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they were in the order of Opisthopora since the male pores opened posterior to the female pores, although the internal male segments are anterior to the female. Theoretical cladistic studies have placed them in the suborder Lumbricina of the order Haplotaxida, but this may change. Other slang names for earthworms include "dew-worm", "rainworm", "nightcrawler", and "angleworm" (from its use as angling hookbaits). Larger terrestrial earthworms are also called megadriles (which translates to "big worms") as opposed to the microdriles ("small worms") in the semiaquatic families Tubificidae, Lumbricidae and Enchytraeidae. The megadriles are characterized by a distinct clitellum (more extensive than that of microdriles) and a vascular system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipalium Kewense
''Bipalium kewense'', also known as the shovel-headed garden worm, is a species of large predatory land planarian with a cosmopolitan distribution. It is sometimes referred to as a "hammerhead flatworm" due to its half-moon-shaped head, but this name is also used to refer to other species in the subfamily Bipaliinae. Description ''Bipalium kewense'' is a very long land planarian. Preserved specimens are up to 20 centimetres in length, and living specimens may be longer. The anterior end ("head") is expanded in a transversal semilunate shape and the body is the narrowest just behind the head, in a region called "neck". The dorsal color is light-brown with five black to grey longitudinal stripes that begin at the neck. The median and marginal stripes are narrow and black, very distinctly marked. The lateral stripes (between the median and marginal stripes) are usually grey, broad and with diffuse margins. The neck is usually marked by an incomplete black collar formed by the uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipalium Adventitium
''Bipalium adventitium'', the wandering broadhead planarian, is a land planarian in the subfamily Bipaliinae. It has been accidentally introduced in the United States, where it is considered invasive. Appearance Most adult individuals of ''B. adventitium'' are in length. The head is expanded and fan-shaped, being easily distinguishable from other common species of ''Bipalium'', such as ''Bipalium kewense'' and '' Bipalium pennsylvanicum'', because these have a head in the shape of a half moon. The body has a yellow to tan color and has one dark dorsal stripe that does not extend over the head. Behaviour and ecology Predation ''Bipalium adventitium'' is known to prey on earthworms. In order to catch its prey, it follows a chemical trail given off by the earthworm. Chemoreceptors on the head are responsible for sensing the trail left by the prey. After finding an earthworm, the planarian quickly crawls over it and wraps itself around the prey, preventing its escape. In addition, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxin
Neurotoxins are toxins that are destructive to nervous tissue, nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insult (medical), insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrodotoxin
Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an Order (biology), order that includes Tetraodontidae, pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish, it is found in several other animals (e.g., in blue-ringed octopus, blue-ringed octopuses, Taricha, rough-skinned newts, and Naticidae, moon snails). It is also produced by certain infectious or symbiotic bacteria like ''Pseudoalteromonas tetraodonis, Pseudoalteromonas'', ''Pseudomonas'', and ''Vibrio'' as well as other species found in symbiotic relationships with animals and plants. Although it produces thousands of intoxications annually and several deaths, it has shown efficacy for the treatment of cancer-related pain in phase II and III clinical trials. Tetrodotoxin is a sodium channel blocker. It inhibits the firing of action potentials in neurons by binding to the voltage-gated sodiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asexual Fragmentation
Fragmentation in multicellular or colonial organisms is a form of asexual reproduction or cloning, where an organism is split into fragments upon maturation and the split part becomes the new individual. The organism may develop specific organs or zones to shed or be easily broken off. If the splitting occurs without the prior preparation of the organism, both fragments must be able to regenerate the complete organism for it to function as reproduction. Fragmentation as a method of reproduction is seen in organisms such as spirogyra, filamentous cyanobacteria, molds, lichens, sponges, acoel flatworms, some annelid worms and sea stars. Fragmentation in various organisms Molds, yeasts and mushrooms, all of which are part of the Fungi kingdom, produce tiny filaments called hyphae. These hyphae obtain food and nutrients from the body of other organisms to grow and fertilize. Then a piece of hyphae breaks off and grows into a new individual and the cycle continues. Many lichens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipalium Kewense
''Bipalium kewense'', also known as the shovel-headed garden worm, is a species of large predatory land planarian with a cosmopolitan distribution. It is sometimes referred to as a "hammerhead flatworm" due to its half-moon-shaped head, but this name is also used to refer to other species in the subfamily Bipaliinae. Description ''Bipalium kewense'' is a very long land planarian. Preserved specimens are up to 20 centimetres in length, and living specimens may be longer. The anterior end ("head") is expanded in a transversal semilunate shape and the body is the narrowest just behind the head, in a region called "neck". The dorsal color is light-brown with five black to grey longitudinal stripes that begin at the neck. The median and marginal stripes are narrow and black, very distinctly marked. The lateral stripes (between the median and marginal stripes) are usually grey, broad and with diffuse margins. The neck is usually marked by an incomplete black collar formed by the uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipalium Adventitium
''Bipalium adventitium'', the wandering broadhead planarian, is a land planarian in the subfamily Bipaliinae. It has been accidentally introduced in the United States, where it is considered invasive. Appearance Most adult individuals of ''B. adventitium'' are in length. The head is expanded and fan-shaped, being easily distinguishable from other common species of ''Bipalium'', such as ''Bipalium kewense'' and '' Bipalium pennsylvanicum'', because these have a head in the shape of a half moon. The body has a yellow to tan color and has one dark dorsal stripe that does not extend over the head. Behaviour and ecology Predation ''Bipalium adventitium'' is known to prey on earthworms. In order to catch its prey, it follows a chemical trail given off by the earthworm. Chemoreceptors on the head are responsible for sensing the trail left by the prey. After finding an earthworm, the planarian quickly crawls over it and wraps itself around the prey, preventing its escape. In addition, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphrodite
A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many taxonomic groups of animals, primarily invertebrates, are hermaphrodites, capable of producing viable gametes of both sexes. In the great majority of tunicates, mollusks, and earthworms, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. Hermaphroditism is also found in some fish species, but is rare in other vertebrate groups. Most hermaphroditic species exhibit some degree of self-fertilization. The distribution of self-fertilization rates among animals is similar to that of plants, suggesting that similar pressures are operating to direct the evolution of selfing in animals and plants. A rough estimate of the number of hermaphroditic animal species ... [...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] |
Peristomium
The peristomium is the first true body segment in an annelid worm's body in the anterior end. It is directly behind the prostomium and contains the mouth, tentacular cirri, and sometimes feeding palps, which may instead occur on the prostomium. If an eversible pharynx is present, it is contained in this segment as well, and can fill up to 20 segments when inverted, depending on the species. The prostomium and peristomium can be variously fused, either completely distinct, or comprising a joint structure of a peristomial ring and a tentacular crown. See also *Prostomium *Pygidium The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is compos ... References {{Reflist Annelid anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
