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Sea Butterflies
The Thecosomata (collective/plural: ''thecosomes'', meaning "case/shell-body"), or sea butterflies, are a taxonomic suborder of small, pelagic, free-swimming sea snails known as holoplanktonic opisthobranch gastropod mollusks, in the order Pteropoda (also included within the informal group Opisthobranchia). Most pteropods have some form of calcified shell, although it is often very light, even translucent. The sea butterflies include some of the world's most abundant gastropod species; as their large numbers are an essential part of the ocean food chain, they are a significant contributor to the oceanic carbon cycle. Morphology Unlike other sea snails, or even land snails, sea butterflies float and swim freely through the ocean, traveling along with the currents. This has led to a number of evolutionary adaptations in their bodies, including complete or near-complete loss of the shell and the gill in several families. Their gastropodal foot has also taken the form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limacina Helicina
''Limacina helicina'' is a species of small swimming planktonic sea snail, in the family Limacinidae. It belongs to the group commonly known as Sea butterfly, sea butterflies (Thecosomata). ''Limacina helicina'' is a keystone species of mesozooplankton in Arctic pelagic ecosystems. The first written record of this species was by Friderich Martens from Spitsbergen in 1675. ''Limacina helicina'' was also observed during a 1773 expedition to the Arctic led by Constantine John Phipps on the ships HMS Racehorse (1757), HMS ''Racehorse'' and on HMS Carcass (1759), HMS ''Carcass'' and the species was Species description, described one year later, in 1774. ''Limacina helicina'' is the type species of the genus ''Limacina''. In contrast to the traditional view, it was shown in 2010 that the distribution of this species is not bipolar; Arctic and Antarctic individuals belong to two genetically distinct species: ''Limacina helicina'' in the Arctic, and ''Limacina antarctica'' in the Anta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod
Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and from the land. There are many thousands of species of sea snails and sea slug, slugs, as well as freshwater snails, freshwater limpets, land snails and slugs. The class Gastropoda is a diverse and highly successful class of mollusks within the phylum Mollusca. It contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Furongian, Late Cambrian. , 721 family (taxonomy), families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently neontology, extant living fossil, with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Butterfly
The Thecosomata (collective/plural: ''thecosomes'', meaning "case/shell-body"), or sea butterflies, are a taxonomic suborder of small, pelagic, free-swimming sea snails known as holoplanktonic opisthobranch gastropod mollusks, in the order Pteropoda (also included within the informal group Opisthobranchia). Most pteropods have some form of calcified shell, although it is often very light, even translucent. The sea butterflies include some of the world's most abundant gastropod species; as their large numbers are an essential part of the ocean food chain, they are a significant contributor to the oceanic carbon cycle. Morphology Unlike other sea snails, or even land snails, sea butterflies float and swim freely through the ocean, traveling along with the currents. This has led to a number of evolutionary adaptations in their bodies, including complete or near-complete loss of the shell and the gill in several families. Their gastropodal foot has also taken the form of two wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodia
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; : parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions. __TOC__ Annelid parapodia Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size and form, reflecting a variety of functions, such as, anchorage, protection and locomotion. General description Parapodia in polychaetes can be uniramous (consisting of one lobe or ramus) but are usually biramous (two lobes or rami). In the latter case, the dorsal lobes are called notopodia and the ventral lobes neuropodia. Both neuropodia and notopodia may possess a bundle of chaetae (neurochaetae and notochaetae respectively ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (: branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamella (surface anatomy), lamellae (folds) contain blood or Coelom#Coelomic fluid, coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including Mollusc, molluscs, crustaceans, insects, fish, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th-century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin and Alfred Russel Wallace proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by changes in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Current
An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents move both horizontally, on scales that can span entire oceans, as well as vertically, with vertical currents (upwelling and downwelling) playing an important role in the movement of nutrients and gases, such as carbon dioxide, between the surface and the deep ocean. Ocean currents flow for great distances and together they create the global conveyor belt, which plays a dominant role in determining the climate of many of Earth's regions. More specifically, ocean currents influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Snail
A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial molluscs, terrestrial gastropod mollusks that have gastropod shell, shells (those without shells are known as slugs). However, it is not always easy to say which species are terrestrial, because some are more or less amphibious between land and fresh water, and others are relatively amphibious between land and salt water. Land snails are a Polyphyly, polyphyletic group comprising at least ten independent evolutionary transitions to terrestrial life (the last common ancestor of all gastropods was marine). The majority of land snails are pulmonates that have a lung and breathe air. Most of the non-pulmonate land snails belong to lineages in the Caenogastropoda, and tend to have a gill and an operculum (gastropod), operculum. The largest clade of non-pulmonate land snails is the Cyclophoroidea, with more than 7,0 ... [...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] |
Oceanic Carbon Cycle
The oceanic carbon cycle (or marine carbon cycle) is composed of processes that exchange carbon between various pools within the ocean as well as between the atmosphere, Earth interior, and the seafloor. The carbon cycle is a result of many interacting forces across multiple time and space scales that circulates carbon around the planet, ensuring that carbon is available globally. The Oceanic carbon cycle is a central process to the global carbon cycle and contains both inorganic carbon (carbon not associated with a living thing, such as carbon dioxide) and organic carbon (carbon that is, or has been, incorporated into a living thing). Part of the marine carbon cycle transforms carbon between non-living and living matter. Three main processes (or pumps) that make up the marine carbon cycle bring atmospheric carbon dioxide (CO2) into the ocean interior and distribute it through the oceans. These three pumps are: (1) the solubility pump, (2) the carbonate pump, and (3) the biologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Shell
The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the Aperture (mollusc), aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group. Shell layers The gastropod shell has three major layers secreted by the Mantle (mollusc), mantle. The calcareous central layer, ostracum, is typically made of calcium carbonate (CaCO3) precipitated into an organic matrix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opisthobranchia
Opisthobranchs () is a now informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping. Euopisthobranchia is a taxon containing a revised collection of opisthobranchs, and that taxon is considered monophyletic. Euopisthobranchia does not include some "traditional" opisthobranchs such as the Sacoglossa and the Acochlidiacea. The subclass Heterobranchia now contains all the species which used to be assigned to Opisthobranchia, plus all the species in the Pulmonata. The subclass Opisthobranchia included species in the order Cephalaspidea (bubble shells and headshield slugs), the sacoglossans, anaspidean sea hares, pelagic sea angels, sea butterflies, and many families of the Nudibranchia. ''Opisthobranch'' means "gills behind" (and to the right) of the heart. In contrast, ''Prosobranch'' means ''gills in front'' (of the hear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
