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Henricia Leviuscula
''Henricia leviuscula'', commonly called the Pacific blood star, it is a species of sea star found along the Pacific coast of North America. Description They can usually be identified by their bright orange-red color, but there can also be many variations from tan to almost purple. The disk can be a mottled gray color. There can also be a saddle-like marking of lilac blotches between the rays, but the rays are not mottled. They commonly have 5 rays (occasionally 4–6). The rays are smooth and appear smooth due to the lack of pedicellariae and spines. The species is relatively small; the diameter is usually over 8 cm and rarely gets larger than 12 cm. As with all seastars the blood star has a madreporite which can be seen in the image below. Reproduction and life history Sexes are dioecious and females are not known to brood young. This statement is in conflict with other sources that state that smaller females brood their young and larger females discharge egg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Stimpson
William Stimpson (February 14, 1832 – May 26, 1872) was a noted 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 cooking stove, famous in its day throughout New England. He also made improvements in rifles, and suggested the placin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedicellariae
A pedicellaria (plural: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). Each pedicellaria is an effector organ with its own set of muscles, neuropils, and sensory receptors and is therefore capable of reflex responses to the environment. Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organisms, and other debris in conjunction with the ciliated epidermis present in all echinoderms. In sea stars Types There are two major types of pedicellaria in sea stars: straight and crossed. Straight pedicellaria are typically larger and located on the body surface, whereas crossed pedicellaria are smaller and found more commonly on stalks, raised above the body surface or in clumps circling the spines. The crossed type is connected to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madreporite
The madreporite is a light colored calcareous opening used to filter water into the water vascular system of echinoderms. It acts like a pressure-equalizing valve. It is visible as a small red or yellow button-like structure, looking like a small wart, on the aboral surface of the central disk of a sea star or sea urchin or the oral surface of Ophiuroidea. Close up, it is visibly structured, resembling a "madrepore" (stone coral, Scleractinia) colony. From this, it derives its name. The water vascular system of the sea star consists of a series of seawater-filled ducts that function in locomotion and feeding and respiration. Its main parts are the madreporite, the stone canal, the ring canal, the radial canals, the lateral canals, and the tube feet. The sieve-like madreporite allows entry of seawater into the stone canal, which connects to the ring canal around the mouth. Five or more radial canals extend from the ring canal, one in each arm above the ambulacral groove. From th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henricia Madreporite
''Henricia'' is a large genus of slender-armed sea stars belonging to the family Echinasteridae. It contains about fifty species. The sea stars from this genus are ciliary suspension-feeders, filtering phytoplankton. Species According to the World Register of Marine Species (WoRMS), the following species belong to this genus Gallery Henricialeviuscula.jpg, ''Henricia leviuscula ''Henricia leviuscula'', commonly called the Pacific blood star, it is a species of sea star found along the Pacific coast of North America. Description They can usually be identified by their bright orange-red color, but there can also be man ...'' Starfish at Castle Rocks P7260899.JPG, ''Henricia ornata'' References Further reading * Catalogue of Life. (2008). Catalogue of Life. (2008). Retrieved May 8, 2010, from Species 2000: http://www.catalogueoflife.org/annual-checklist/2008/browse_taxa.php?selected_taxon=991569 * Clark, A.M. & Downey, M.E. (1992) Starfishes of the Atlantic. Chapman & H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioecious
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is biparental reproduction. Dioecy has costs, since only about half the population directly produces offspring. It is one method for excluding self-fertilization and promoting allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Plants have several other methods of preventing self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility. Dioecy is a dimorphic sexual system, alongside gynodioecy and androdioecy. In zoology In zoology, dioecious species may be opposed to hermaphroditic species, meaning that an individual is either male or female, in which case the synonym gonochory is more often used. Most animal species are dioecious (gon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), that is complex but it is not a species complex. A species complex is in most cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliated
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] |
Intertidal Zone
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species of life, such as seastars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the ''littoral zone'' or '' seashore'', although those can be defined as a wider region. The well-known area also includes steep rocky cliffs, sandy beaches, bogs or wetlands (e.g., vast mudflats). The area can be a narrow strip, as in Pacific islands that have only a narrow tidal range, or can include many meters of shoreline where shallow beach slopes interact with high tidal excursion. The peritidal zone is similar but somewhat wider, extending from above the highest tide level to below the lowest. Organisms in the intertidal zone are adapted to an environment of harsh extremes, living in water pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctonoe Vittata
''Arctonoe vittata'' is a species of scaled polychaete worms commonly known as a "scale worm". This species often lives as a commensal of another marine animal. Description At least thirty pairs of elytra, scale-like modifications to the dorsal cirri, conceal the animal's body. These are on alternate segments and do not meet dorsally, leaving the central line of the body uncovered. ''A. vittata'' is a pale yellowish colour, with a few faint transverse bands, and a dark stripe located across segments 7 and 8. It can grow to a length of but is usually shorter. It can be distinguished from the otherwise similar '' Arctonoe pulchra'' by the absence of a dark spot on each scale. Distribution ''A. vittata'' is native to the eastern Pacific Ocean. Its range extends from the Bering Strait to Ecuador, and as far west as Japan. Its depth range is from the middle shore down to about . Ecology The species forms a commensal relationship with the gumboot chiton, living on its gills. It al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
