|
Pteropods
Pteropoda (common name pteropods, from the Greek meaning "wing-foot") are specialized free-swimming pelagic sea snails and sea slugs, marine opisthobranch gastropods. Most live in the top 10 m of the ocean and are less than 1 cm long. The monophyly of Pteropoda is the subject of a lengthy debate; they have even been considered as paraphyletic with respect to cephalopods. Current consensus, guided by molecular studies, leans towards interpreting the group as monophyletic. Pteropoda encompasses the two clades Thecosomata, the sea butterflies, and Gymnosomata, the sea angels. The Thecosomata ( "case-body") have a shell, while the Gymnosomata ("naked body") do not. The two clades may or may not be sister taxa; if not, their similarity (in that they are both pelagic, small, and transparent, and both groups swim using wing-like flaps ( parapodia) which protrude from their bodies) may reflect adaptation to their particular lifestyle. Taxonomy The group Pteropoda was establis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Butterflies
Sea butterflies, scientific name Thecosomata (thecosomes, "case / shell-body"), are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified shell, although it is often very light and / or transparent. The sea butterflies include some of the world's most abundant gastropod species, and because of their large numbers are an essential part of the food chain, and a significant contributor to the oceanic carbon cycle. The sea butterflies are included in the Pteropoda order, and are also included in the informal group Opisthobranchia. Morphology Sea butterflies float and swim freely in the water, and are carried along with the currents. This has led to a number of adaptations in their bodies. The shell and the gill have disappeared in several families. Their gastropodal foot has taken the form of two wing-like lobes, or '' parapodia'', which propel the animal throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thecosomata
Sea butterflies, scientific name Thecosomata (thecosomes, "case / shell-body"), are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified shell, although it is often very light and / or transparent. The sea butterflies include some of the world's most abundant gastropod species, and because of their large numbers are an essential part of the food chain, and a significant contributor to the oceanic carbon cycle. The sea butterflies are included in the Pteropoda order, and are also included in the informal group Opisthobranchia. Morphology Sea butterflies float and swim freely in the water, and are carried along with the currents. This has led to a number of adaptations in their bodies. The shell and the gill have disappeared in several families. Their gastropodal foot has taken the form of two wing-like lobes, or ''parapodia'', which propel the animal through the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theropoda
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Theropods first appeared during the Carnian age of the late Triassic period 231.4 million years ago ( Ma) and included all the large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 10,500 living species. Biology Diet and teeth Theropods exhibit a wide range of diets, from insectivores to herbivores and carnivores. Strict carnivory has always been considered the ancestral diet for theropods as a group, and a wider variety of diets was historically considered a characteris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic groups are typically characterised by shared derived characteristics ( synapomorphies), which distinguish organisms in the clade from other organisms. An equivalent term is holophyly. The word "mono-phyly" means "one-tribe" in Greek. Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic group'' consists of all of the descendants of a common ancestor minus one or more monophyletic groups. A '' polyphyletic group'' is characterized by convergent features or habits of scientific interest (for example, night-active primates, fruit trees, aquatic insects). The features by which a polyphyletic group is differentiated from others are not inherited from a common ancestor. These definitions have t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterotracheoidea
The Pterotracheoidea is, according to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), a taxonomic superfamily of sea snails or sea slugs, marine gastropod molluscs in the clade Littorinimorpha. They are commonly called heteropods or sea elephants. Taxonomy This superfamily comprises four families (classification based on Newman (superfamily Carinarioidea, pp. 804–808. In: Beesley ''et al''., 1998), that is also used by the taxonomy of the Gastropoda by Bouchet & Rocroi (2005): * Family Pterotracheidae Rafinesque, 1814 * Family Atlantidae Rang, 1829 * † Family Bellerophinidae Destombes, 1984 * Family Carinariidae Blainville 1818 Habitat These holoplanktonic snails are found floating or swimming in tropical to subtropical open oceans and seas at a depth of maximum 200 to 300 m Anatomy These snails have adapted themselves to a pelagic living : * a transparent body and shell * the foot has evolved into a swimming fin that produces motion through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaucus (gastropod)
''Glaucus'' is a genus of small blue pelagic sea slugs. They are aeolid nudibranchs,Bouchet, P.; Gofas, S. (2013)''Glaucus'' Forster, 1777.Accessed through: World Register of Marine Species on 2013-07-17 ranging in size from . They feed on colonial cnidarians such as Portuguese man o' wars, blue buttons, and purple sails. They can produce painful and potentially dangerous stings when handled, as they store the venomous nematocysts of their prey. ''Glaucus'' is the only genus in the family Glaucidae. It includes five species. Taxonomic history The genus ''Glaucus'' was established by monotypy in 1777 by the British naturalist Johann Reinhold Forster. He described specimens of ''Glaucus atlanticus'' recovered during the second voyage of James Cook aboard . The genus is named after the Greek sea-god Glaucus. In 1848, the German naturalist Johannes Gistel provided the substitute name ''Dadone'' for ''Glaucus''. But it is unnecessary and is now regarded as invalid.Bouchet, P. (201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylliroe
''Phylliroe'' is a genus of average sized (up to ), highly transparent pelagic nudibranchs, marine gastropod molluscs in the order Opisthobranchia, that consists of two known species. It is notable for being an open-ocean hunter that resembles a fish in body plan and locomotion, an example of convergent evolution. Distribution and habitat * ''P. atlantica'' occurs in the (sub) tropical waters of the Atlantic and Pacific oceans. * ''P. bucephalum'' is known from the Mediterranean. Ecology Juveniles of ''P. bucephalum'' are found exclusively feeding on the bell of the hydromedusa ''Zanclea costata'' (this junior synonym was given precedence over ''Mnestra parasites''). At first the nudibranch is attached to the inside of the bell of the meduse with its very small foot. It sucks tissue from the ring, radial canals and manubrium of the meduse and grows from 1.6 mm to 11 mm in just ten days, while the meduse shrinks. When the slug is as big as the meduse, it starts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Alexandre Lesueur
Charles Alexandre Lesueur (1 January 1778 in Le Havre – 12 December 1846 in Le Havre) was a French naturalist, artist, and explorer. He was a prolific natural-history collector, gathering many type specimens in Australia, Southeast Asia, and North America, and was also responsible for describing numerous species, including the spiny softshell turtle ('' Apalone spinifera''), smooth softshell turtle ('' A. mutica''), and common map turtle ('' Graptemys geographica''). Both Mount Lesueur and Lesueur National Park in Western Australia are named in his honor. Early life Charles Alexandre Lesueur was born on January 1, 1778, to Jean-Baptiste Denis Lesueur and Charlotte Thieullent. Charlotte died when Charles was sixteen years old, and Charles' maternal grandmother took care of him and his siblings. Charles attended the Collège du Havre and possibly the Ecole publique des mathématiques et d'hydrographie. He was in military service in a cadet battalion at age fifteen and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
François Péron
François Auguste Péron (22 August 1775 – 14 December 1810) was a French naturalist and explorer. Life Péron was born in Cérilly, Allier, in 1775, the son of a tailor (not a harness maker as is frequently asserted). Although intended for the priesthood, due to the Revolution, Péron reluctantly joined the 2nd Allier Volunteer Battalion in 1792 and helped defend besieged Landau. In the following year he was wounded and taken prisoner by Prussian forces near Hochspeyer in the Pfalzwald. Imprisoned in the fortress of Magdeburg he was not repatriated to France until 1794. Having lost the sight of an eye, Péron was invalided out of the army. For two years he was Town Clerk in Cérilly before gaining a scholarship to study medicine in Paris. While in Paris, Péron changed interests towards zoology, spending time at the Muséum d'histoire naturelle. In 1800, after an unhappy love affair, he sought to join Nicolas Baudin's expedition to Australian waters as an anthropological o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Cuvier
Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French naturalist and zoologist, sometimes referred to as the "founding father of paleontology". Cuvier was a major figure in natural sciences research in the early 19th century and was instrumental in establishing the fields of comparative anatomy and paleontology through his work in comparing living animals with fossils. Cuvier's work is considered the foundation of vertebrate paleontology, and he expanded Linnaean taxonomy by grouping classes into phylum, phyla and incorporating both fossils and living species into the classification. Cuvier is also known for establishing extinction as a fact—at the time, extinction was considered by many of Cuvier's contemporaries to be merely controversial speculation. In his ''Essay on the Theory of the Earth'' (1813) Cuvier proposed that now-extinct species had been wiped out by periodic catastrophic flooding events. In th ... [...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 proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by change in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations that interlock with those of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodia
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: 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 gas exchange, 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 notoch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Pteropods")
.jpg "Click for more on -> Sea Butterflies")
