|
Terrestrial Molluscs
Terrestrial molluscs or land molluscs (mollusks) are an ecology, ecological group that includes all molluscs that live on land in contrast to Freshwater mollusc, freshwater and Sea snail, marine molluscs. They probably first occurred in the Carboniferous, arising from freshwater molluscs#Freshwater gastropods, freshwater ones. Characteristics This group includes land snails and land slugs. Loss of the shell has taken place many times in different groups that are not evolutionarily closely related, and land snails and slugs are most often treated together as a single group in specialized malacology, malacological literature.Barker G. M. (ed.) The biology of terrestrial molluscs'. CABI Publishing, 2001, 558 pp. .Barker G. M. (ed.) Natural enemies of terrestrial molluscs'. CABI Publishing, 2004, 644 pp. . All terrestrial molluscs belong to the class Gastropoda. However, colonization of the land took place several times during the evolutionary past, and as a result terrestrial mollus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helix Pomatia 89a
A helix (; ) is a shape like a cylindrical coil spring or the thread of a machine screw. It is a type of smoothness (mathematics), smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as double helix, two intertwined helices, and many proteins have helical substructures, known as alpha helix, alpha helices. The word ''helix'' comes from the Greek language, Greek word , "twisted, curved". A "filled-in" helix – for example, a "spiral" (helical) ramp – is a surface called a ''helicoid''. Properties and types The pitch of a helix is the height of one complete helix turn (angle), turn, measured parallel to the axis of the helix. A double helix consists of two (typically congruence (geometry), congruent) helices with the same axis, differing by a translation along the axis. A circular helix (i.e. one with constant radius) has constant band curvature and constant Torsion of curves, torsion. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desert
A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or Semi-arid climate, semi-arid. This includes much of the Polar regions of Earth, polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night strain the Rock (geology), rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting frag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicinidae
Helicinidae is a family of small tropical land snails, terrestrial operculate gastropod mollusks in the superfamily Helicinoidea. Name These snails are not at all closely related to the air-breathing land snails, despite a superficial similarity of the shells. The name "Helicinidae" immediately reminds most people of "Helicidae", the most well-known group of land snails including e.g. ''Helix pomatia'', but the important two letters "ni" only from the Latin diminutive of the latter name alluding to superficial similarities of otherwise completely different things. Distribution These snails are found in tropical and subtropical areas but they have an odd distribution: they are restricted to the Caribbean islands and some Indo-Pacific and Pacific islands, as well as the edge of the Asian and Australian continents. Some species are found in the southern United States, from Louisiana to Florida; others in Central and South America. Taxonomy Helicinidae belongs to superfamily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclophoroidea
Cyclophoroidea is a superfamily of land snails with an operculum, terrestrial gastropods within the order Architaenioglossa, that belongs to the subclass Caenogastropoda.Bouchet, P.; Rosenberg, G.; Gofas, S. (2015). Cyclophoroidea Gray, 1847. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=153654 on 2015-02-16 These terrestrial gastropods have lost the ctenidium (comb-like respiratory apparatus) and osphradium, and the pallial cavity has been modified as a lung. Taxonomy According to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), this superfamily consists of the following families: *Family Aciculidae Gray, 1850 *Family Alycaeidae Alycaeidae is a taxonomic family of small to large tropical land snails with an operculum, terrestrial gastropod mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). ... W. T. Blanford, *Genu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Snail
Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible Gastropod shell, shell. Definition Determining whether some gastropods should be called sea snails is not always easy. Some species that live in brackish water (such as certain Neritidae, neritids) can be listed as either freshwater snails or marine snails, and some species that live at or just above the high tide level (for example, species in the genus ''Truncatella (gastropod), Truncatella'') are sometimes considered to be sea snails and sometimes listed as land snails. Anatomy Sea snails are a very large and diverse group of animals. Most snails that live in salt water respire using a gill or gills; a few species, though, have a lung, are intertidal, and are active only at low tide w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (gastropod)
An operculum (; ) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails, including the Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture (mollusc), aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture (mollusc), aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which are not capable of closing the shell aperture. Opercula have sometimes been modifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosobranchia
Prosobranchia was a large Taxonomy (biology), taxonomic Class (biology), subclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s. It has however been proven to be polyphyly, polyphyletic (consisting of more than one lineage (evolution), lineage of descent). Generally speaking in biology Taxonomy (biology), taxonomy is required to reflect phylogeny, in other words the classification of a group must reflect its evolutionary descent, as far as that is known, so the taxon Prosobranchia is no longer considered suitable to be used. One can still encounter this subclass used as if it is still valid in many texts and websites. Although Prosobranchia is no longer generally accepted as a taxon by people who study living Mollusca, still the term prosobranch is legitimately used as an anatomically descriptive adjective or noun, and the taxon Prosobranchia is still sometimes used by paleontologists. ''Prosobranch'' means ''gills in front'' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonata
Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includes many land and freshwater families, and several marine families. The taxon Pulmonata as traditionally defined was found to be polyphyletic in a molecular study per Jörger ''et al.'', dating from 2010. Pulmonata are known from the Carboniferous period to the present. Pulmonates have a single atrium and kidney, and a concentrated symmetrical nervous system. The mantle cavity is on the right side of the body, and lacks gills, instead being converted into a vascularised lung. Most species have a shell, but no operculum, although the group does also include several shell-less slugs. Pulmonates are hermaphroditic, and some groups possess love darts. Linnean taxonomy The taxonomy of this group according to the taxonomy of the Gastropoda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pomatiasidae - Pomatias Elegans-000
The family Pomatiidae is a taxonomic family of small operculate land snails, terrestrial gastropod mollusks that can be found over the warmer parts of the Old World. In the older literature, this family is designated as Pomatiasidae. This family is a lineage closely related to the Littorinidae (periwinkles) common in coastal habitat. They have adapted to terrestrial life and are thus sometimes called "land winkles". They are defined by a chalky operculum at the rear end of the body, the shape of their thick shell and their mouth and a characteristic spiral sculpture. The sexes are separate and can sometimes be recognised because the female shell is slightly larger than the male shell. Taxonomy According to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), the family Pomatiidae consisted of two subfamilies: *subfamily Pomatiinae Newton, 1891 (1828) - synonyms: Cyclostomatidae Menke, 1828; Cyclotopsinae Kobelt & Möllendorff, 1898; Ericiidae Wenz, 1915 *subfamily Annula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
