|
Kamptozoa
Entoprocta (), or Kamptozoa , is a phylum of mostly sessile aquatic animals, ranging from long. Mature individuals are goblet-shaped, on relatively long stalks. They have a "crown" of solid tentacles whose cilia generate water currents that draw food particles towards the mouth, and both the mouth and anus lie inside the "crown". The superficially similar Bryozoa (Ectoprocta) have the anus outside a "crown" of hollow tentacles. Most families of entoprocts are colonial, and all but 2 of the 150 species are marine. A few solitary species can move slowly. Some species eject unfertilized ova into the water, while others keep their ova in brood chambers until they hatch, and some of these species use placenta-like organs to nourish the developing eggs. After hatching, the larvae swim for a short time and then settle on a surface. There they metamorphose, and the larval gut rotates by up to 180°, so that the mouth and anus face upwards. Both colonial and solitary species also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a lophophore, a "crown" of tentacles used for filter feeding. Most marine bryozoans live in tropical waters, but a few are found in oceanic trenches and polar waters. The bryozoans are classified as the marine bryozoans (Stenolaemata), freshwater bryozoans (Phylactolaemata), and mostly-marine bryozoans (Gymnolaemata), a few members of which prefer brackish water. 5,869living species are known. At least two genera are solitary (''Aethozooides'' and ''Monobryozoon''); the rest are colonial. The terms Polyzoa and Bryozoa were introduced in 1830 and 1831, respectively. Soon after it was named, another group of animals was discovered whose filtering mechanism looked similar, so it was included in Bryozoa until 1869, when the two groups were no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a lophophore, a "crown" of tentacles used for filter feeding. Most marine bryozoans live in tropical waters, but a few are found in oceanic trenches and polar waters. The bryozoans are classified as the marine bryozoans (Stenolaemata), freshwater bryozoans (Phylactolaemata), and mostly-marine bryozoans (Gymnolaemata), a few members of which prefer brackish water. 5,869living species are known. At least two genera are solitary (''Aethozooides'' and ''Monobryozoon''); the rest are colonial. The terms Polyzoa and Bryozoa were introduced in 1830 and 1831, respectively. Soon after it was named, another group of animals was discovered whose filtering mechanism looked similar, so it was included in Bryozoa until 1869, when the two groups were no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hinrich Nitsche
Hinrich Nitsche (14 February 1845, in Breslau – 8 November 1902, in Tharandt) was a German zoologist. He was a son-in-law to geographer Oscar Peschel (1826-1875). He studied zoology at the Universities of Heidelberg and Berlin, obtaining his doctorate at the latter institution in 1868. After graduation, he worked as an assistant to Rudolf Leuckart at the University of Leipzig. During the Franco-Prussian War, he served as a volunteer medical assistant. In 1875, he became an associate professor of zoology at Leipzig, and during the following year was appointed professor of zoology at the Royal Saxon Academy of Forestry in Tharandt. In 1869-70 he divided the phylum Bryozoa into two groups, Endoprocta and Ectoprocta, with the latter group of animals being characterized by having its anus outside of the crown of tentacles, as opposed to Endoprocta. Today the term "Ectoprocta" is considered to be synonymous with Bryozoa. The herpetological species Nitsche's bush viper (''Atheris n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stolon
In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons. In botany In botany, stolons are stems which grow at the soil surface or just below ground that form adventitious roots at the nodes, and new plants from the buds. Stolons are often called runners. Rhizomes, in contrast, are root-like stems that may either grow horizontally at the soil surface or in other orientations underground. Thus, not all horizontal stems are called stolons. Plants with stolons are called stoloniferous. A stolon is a plant propagation strategy and the complex of individuals formed by a mother plant and all its clones produced from stolons form a single genetic individual, a genet. Morphology Stolons may or may not have long internodes. The leaves along the stolon are usually very small, but in a few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calyx (zoology)
Calyx is a term used in animal anatomy for some cuplike areas or structures. Etymology Latin, from ''calyx'' (from Ancient Greek ''κάλυξ, ''case of a bud, husk"). Cnidarians The spicules containing the basal portion of the upper tentacular part of the polyp of some soft corals (also called ''calice''). Entoprocta A body part of the Entoprocta from which tentacles arise and the mouth and anus are located. Echinoderms The body disk that is covered with a leathery tegumen containing calcareous plates (in crinoids and ophiuroids the main part of the body where the viscera are located). Humans Either a minor calyx in the kidney, a conglomeration of two or three minor calyces to form a major calyx, or the Calyx of Held, a particularly large synapse in the mammalian auditory central nervous system, named by H. Held in his 1893 article ''Die centrale Gehörleitung'', due to its flower-petal-like shape. Satzler, K., L. F. Sohl, et al. (2002). "Three-dimensional reconstruction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protonephridia
The nephridium (plural ''nephridia'') is an invertebrate organ, found in pairs and performing a function similar to the vertebrate kidneys (which originated from the chordate nephridia). Nephridia remove metabolic wastes from an animal's body. Nephridia come in two basic categories: metanephridia and protonephridia. All nephridia- and kidney- having animals belong to the clade Nephrozoa. Metanephridia A metanephridium (''meta'' = "after") is a type of excretory gland found in many types of invertebrates such as annelids, arthropods and mollusca. (In mollusca, it is known as the Bojanus organ.) A metanephridium typically consists of a ciliated funnel opening into the body cavity, or coelom connected to a duct which may be variously glandularized, folded or expanded (vesiculate) and which typically opens to the organism's exterior. These ciliated tubules pump water carrying surplus ions, metabolic waste, toxins from food, and useless hormones out of the organism by directing them ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelom
The coelom (or celom) is the main body cavity in most animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, it remains undifferentiated. In the past, and for practical purposes, coelom characteristics have been used to classify bilaterian animal phyla into informal groups. Etymology The term ''coelom'' derives from the Ancient Greek word (), meaning 'cavity'. Structure Development The coelom is the mesodermally lined cavity between the gut and the outer body wall. During the development of the embryo, coelom formation begins in the gastrulation stage. The developing digestive tube of an embryo forms as a blind pouch called the archenteron. In Protostomes, the coelom forms by a process known as schizocoely. The archenteron initially forms, and the mesoderm splits into two layers: the first attaches to the body wall or ectoderm, forming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insects, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Animals can be divided into species that undergo complete metamorphosis (" holometaboly"), incomplete metamorphosis ("hemimetaboly"), or no metamorphosis (" ametaboly"). Scientific usage of the term is technically precise, and it is not applied to general aspects of cell growth, including rapid growth spurts. Generally organisms with a larva stage undergo metamorphosis, and during metamorphosis the organism loses larval characteristics. References to "metamorphosis" in mammals are imprecise and only colloquial, but historically idealist ideas of transformation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cilia
The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projection that extends from the surface of the much larger cell body. Eukaryotic flagella found on sperm cells and many protozoans have a similar structure to motile cilia that enables swimming through liquids; they are longer than cilia and have a different undulating motion. There are two major classes of cilia: ''motile'' and ''non-motile'' cilia, each with a subtype, giving four types in all. A cell will typically have one primary cilium or many motile cilia. The structure of the cilium core called the axoneme determines the cilium class. Most motile cilia have a central pair of single microtubules surrounded by nine pairs of double microtubules called a 9+2 axoneme. Most non-motile cilia have a 9+0 axoneme that lacks the central pair of mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zooid
A zooid or zoöid is a single animal that is part of a colonial animal. This lifestyle has been adopted by animals from separate unrelated taxa. Zooids are multicellular; their structure is similar to that of other solitary animals. The zooids can either be directly connected by tissue (e.g. corals, Catenulida, Siphonophorae, Pyrosome or Ectoprocta) or share a common exoskeleton (e.g. Bryozoa or Pterobranchia). The colonial organism as a whole is called a ''zoon'' , plural ''zoa'' (from Ancient Greek meaning animal; plural , ). Zooids can exhibit polymorphism. For instance, extant bryozoans may have zooids adapted for different functions, such as feeding, anchoring the colony to the substratum and for brooding embryos. However, fossil bryozoans are only known by the colony structures that the zooids formed during life. There are correlations between the size of some zooids and temperature. Variations in zooid size within colonies of fossils can be used as an indicator of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anus
The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, depending on the type of animal, includes: matter which the animal cannot digest, such as bones; Summary at food material after the nutrients have been extracted, for example cellulose or lignin; ingested matter which would be toxic if it remained in the digestive tract; and dead or excess gut bacteria and other endosymbionts. Amphibians, reptiles, and birds use the same orifice (known as the cloaca) for excreting liquid and solid wastes, for copulation and egg-laying. Monotreme mammals also have a cloaca, which is thought to be a feature inherited from the earliest amniotes via the therapsids. Marsupials have a single orifice for excreting both solids and liquids and, in females, a separate vagina for reproduction. Female placental mamm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
