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Nuda Proprietà Vendesi
Beroidae is a family of ctenophores or comb jellies more commonly referred to as the beroids. It is the only known family within the monotypic order Beroida and the class Nuda. They are distinguished from other comb jellies by the complete absence of tentacles, in both juvenile and adult stages. Species of the family Beroidae are found in all the world's oceans and seas and are free-swimmers that form part of the plankton. Anatomy Some members of the diverse genus ''Beroe'' may occasionally attain a length of up to , though most species and individuals are less than about 10 cm; '' Neis cordigera'' is among the largest species in the class, often exceeding in length. The body is melon or cone-shaped with a wide mouth and pharynx and a capacious gastrovascular cavity. Many meridional canals branch off this and form a network of diverticulae in the mesogloea. There are no tentacles but there are a row of branched papillae, forming a figure of eight around the aboral tip. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beroe (ctenophore)
''Beroe'', commonly known as the cigar comb jellies, is a genus of comb jellies in the family Beroidae. ''Beroe'' exhibits bioluminescence. Anatomy Inside the mouths of beroid ctenophores, macrocilia are present and essential for feeding. Each macrocillium contains multiple axonemes that are surrounded by a common membrane with a distinct capping structure at the distal tip. The cap structure consists of extensions of axonemal microtubules that are embedded in an electron dense matrix to form pointed projections or "teeth". During the beat cycle of macrocilia, these teeth shift from a straight to hooked configuration which is thought to aid ingestion and break up prey. These macrocilia are diverse amongst Beroe families and can be used to identify ctenophores by way of morphological differences. According to the World Register of Marine Species, the following species are members of this genus: *'' Beroe abyssicola'' Mortensen, 1927 *'' Beroe australis'' Agassiz & Mayer, 1899 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beroe Gracilis
''Beroe gracilis'' is a species of comb jelly in the family Beroidae. It is a free-swimming species found in the North Sea, the Atlantic Ocean and the Mediterranean Sea. Description ''Beroe gracilis'' is a translucent, elongated, hollow, cylindrical animal with a maximum length of about . Like the other members of the family Beroidae, it has no tentacles. The anterior end, with the gaping mouth at its tip, is slightly broader than the closed, posterior end. At the posterior end there is a statocyst, a flattened structure shaped like a figure-of-eight. From this, eight rows of combs with cilia radiate and extend three-quarters of the way along the body wall; it is the beating of these cilia that drive the animal forward, and their movement creates characteristic multicoloured sparkles. The general colour of the body wall is slightly milky, sometimes bluish or pinkish. The gut and its diverticula can be seen through the body wall. Distribution and habitat ''Beroe gracilis'' occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Friedrich Von Eschscholtz
Johann Friedrich Gustav von Eschscholtz (1 November 1793 – 7 May 1831)Sterling (1997) was a Baltic German physician, naturalist, and entomologist. He was one of the earliest scientific explorers of the Pacific region, making significant collections of flora and fauna in Alaska, California, and Hawaii. Biography Eschscholtz was born in the Livonians, Livonian city of Tartu, Dorpat, then part of the Russian Empire. His parents, Johann Gottfried and Katherine Hedwig Ziegler Eschscholtz were ethnic Baltic Germans. He studied medicine and zoology at the University of Tartu, University of Dorpat and served as an assistant to Carl Friedrich von Ledebour, a professor of botany.McKelvey Eschscholtz received a medical degree in 1815. First voyage On the recommendation of Ledebour, Eschscholtz served as surgeon and naturalist on the Russian expeditionary ship ''Rurik expedition, Rurik'' under the command of Otto von Kotzebue.Daum (2019) From 1815 to 1818 the expedition circumnavigated th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
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. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists 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. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel Phenotypic trait, character or character state that has evolution, evolved from its ancestral form (or Plesiomorphy and symplesiomorphy, plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxon, taxa and is therefore Hypothesis#Scientific hypothesis, hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies Homology (biology), homology. Examples of apomorphy are the presence of Terrestrial locomotion#Posture, erect gait, fur, Evolution of mammalian auditory ossicles, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a Terrestrial locomotion#Posture, sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tentaculata
Tentaculata is a class of comb jellies, one of two classes in the phylum Ctenophora. The common feature of this class is a pair of long, feathery, contractile tentacles, which can be retracted into specialised ciliated sheaths. In some species, the primary tentacles are reduced and they have smaller, secondary tentacles. The tentacles have colloblasts, which are sticky-tipped cells that trap small prey. Body size and shape varies widely. The group includes the small, oval sea gooseberries found on both Atlantic and Pacific coasts. The more flattened species of the genus '' Mnemiopsis'', about long, are common on the upper Atlantic coast; it has a large mouth and mainly feeds on larval molluscs and copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...s. This species is bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonad
A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of Spermatozoon, spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals (and some humanssee Ovotesticular syndrome) have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone (LH) and follicle-stimulating hormone (FSH), produced and secreted by gonadotropic cell, gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone (GnRH) produced in the hypothalamus. Development The gonads develop f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspian Sea
The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, west of the broad steppe of Central Asia, south of the fertile plains of Southern Russia in Eastern Europe, and north of the mountainous Iranian Plateau. It covers a surface area of (excluding the highly saline lagoon of Garabogazköl to its east), an area approximately equal to that of Japan, with a volume of . It has a salinity of approximately 1.2% (12 g/L), about a third of the salinity of average seawater. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the southwest, Iran to the south, and Turkmenistan to the southeast. The name of the Caspian Sea is derived from the ancient Iranian peoples, Iranic Caspians, Caspi people. The sea stretches from north to south, with an average width of . Its gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anchovy
An anchovy is a small, common forage fish of the Family (biology), family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 16 genera; they are found in the Atlantic, Indian and Pacific Oceans, and in the Black Sea and the Mediterranean Sea. Anchovies are usually classified as oily fish. Taxonomy Anchovies are classified into two subfamilies and 16 genera: * Superfamily Engrauloidea ** Genus †''Clupeopsis'' Casier, 1946 ** Genus †''Monosmilus'' Capobianco et al, 2020 ** Family Engraulidae Theodore Gill, Gill, 1861 *** Subfamily Engraulinae Theodore Gill, Gill, 1861 **** Genus ''Amazonsprattus'' Tyson R. Roberts, Roberts, 1984 **** Genus ''Anchoa'' David Starr Jordan, D. S. Jordan & Barton Warren Evermann, Evermann, 1927 **** Genus ''Anchovia'' D. S. Jordan & Evermann, 1895 **** Genus ''Anchoviella'' Henry Weed Fowler, Fowler, 1911 **** G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Sea
The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia (country), Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is Inflow (hydrology), supplied by major rivers, principally the Danube, Dnieper and Dniester. Consequently, while six countries have a coastline on the sea, its drainage basin includes parts of 24 countries in Europe. The Black Sea, not including the Sea of Azov, covers , has a maximum depth of , and a volume of . Most of its coasts ascend rapidly. These rises are the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Caucasus Mountains to the east, and the Crimean Mountains to the mid-north. In the west, the coast is generally small floodplains below foothills such as the Strandzha; Cape Emine, a dwindling of the east end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
