|
Small-spotted Catshark
The small-spotted catshark (''Scyliorhinus canicula''), also known as the sandy dogfish, lesser-spotted dogfish, rough-hound or morgay (in Scotland and Cornwall), is a catshark of the family Scyliorhinidae. It is found on the continental shelves and the uppermost continental slopes off the coasts of Norway and the British Isles south to Senegal and in the Mediterranean, between latitudes 63° N and 12° N. It can grow up to a length of , and it can weigh more than . It is found primarily over sandy, gravelly, or muddy bottoms from depths of a few metres down to 400 m.Rodriguez-Cabello, C., Sanchez, F., Olaso, I. 2007. Distribution patterns and sexual segregations of ''Scyliorhinus canicula'' (L.) in the Cantabrian Sea. ''Journal of Fish Biology''. 70: 1568–1586 ''S. canicula'' is one of the most abundant elasmobranchs in the northeast Atlantic and Mediterranean Sea. The majority of the populations are stable in most areas.Ballard, W., Mellinger, J., Lechenault, H. 2005. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was born in Råshult, the countryside of Småland, in southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spawning
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mosquitoes and corals, which are actually small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN Red List Of Threatened Species
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The aim of the International Union for Conservation of Nature, IUCN Red List is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to reduce species extinction. According to International Unio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least-concern Species
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent. Species cannot be assigned the "Least Concern" category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status. Evaluation Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc. Around 20% of least concern taxa (3261 of 15636) in the IUCN database still use the code "LR/lc", which indicates they have not been re-evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurulation
Neurulation refers to the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube. The embryo at this stage is termed the neurula. The process begins when the notochord induces the formation of the central nervous system (CNS) by signaling the ectoderm germ layer above it to form the thick and flat neural plate. The neural plate folds in upon itself to form the neural tube, which will later differentiate into the spinal cord and the brain, eventually forming the central nervous system. Computer simulations found that cell wedging and differential proliferation are sufficient for mammalian neurulation. Different portions of the neural tube form by two different processes, called primary and secondary neurulation, in different species. * In primary neurulation, the neural plate creases inward until the edges come in contact and fuse. * In secondary neurulation, the tube forms by hollowing out of the interior of a solid precur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blastocoel
The blastocoel (), also spelled blastocoele and blastocele, and also called cleavage cavity, or segmentation cavity is a fluid-filled or yolk-filled cavity that forms in the blastula during very early embryonic development. At this stage in mammals the blastula develops into the blastocyst containing an inner cell mass, and outer trophectoderm. It develops following cleavage of the zygote after fertilization. It is the first cell cavity formed as the embryo enlarges, and is the essential precursor for the differentiated gastrula. In the ''Xenopus'' a very small cavity has been described in the two-cell stage of development. In mammals After fertilization, the zygote undergoes mitotic divisions during rotational cleavage resulting in daughter cells known as blastomeres until they are at the 16-cell stage called the morula. The morula is a solid ball of cells that has a small group of internal cells surrounded by a larger group of external cells. Following further cleavages and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrulation
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals the blastocyst is reorganized into a multilayered structure known as the gastrula. Before gastrulation, the embryo is a continuous epithelial sheet of cells; by the end of gastrulation, the embryo has begun differentiation to establish distinct cell lineages, set up the basic axes of the body (e.g. dorsal-ventral, anterior-posterior), and internalized one or more cell types including the prospective gut. In triploblastic organisms, the gastrula is trilaminar (three-layered). These three germ layers are the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer).Mundlos 2009p. 422/ref>McGeady, 2004: p. 34 In diploblastic organisms, such as Cnidaria and Ctenophora, the gastrula has only ectoderm and endoderm. The two layers are also sometimes referred to as the ''hypoblast'' and ''epiblast''. Sponges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personality Traits
In psychology, trait theory (also called dispositional theory) is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of ''traits'', which can be defined as habitual patterns of behaviour, thought, and emotion. According to this perspective, traits are aspects of personality that are relatively stable over time, differ across individuals (e.g. some people are outgoing whereas others are not), are relatively consistent over situations, and influence behaviour. Traits are in contrast to states, which are more transitory dispositions. In some theories and systems, traits are something a person either has or does not have, but in many others traits are dimensions such as extraversion vs. introversion, with each person rating somewhere along this spectrum. There are two approaches to define traits: as internal causal properties or as purely descriptive summaries. The internal causal definition states that traits influence our behav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exeter University
, mottoeng = "We Follow the Light" , established = 1838 - St Luke's College1855 - Exeter School of Art1863 - Exeter School of Science 1955 - University of Exeter (received royal charter) , type = Public , endowment = £49.5 million , budget = £503.1 million , chancellor = Sir Michael Barber , vice_chancellor = Lisa Roberts , head_label = Visitor , head = Charles III '' ex officio'' , city = Exeter, DevonPenryn, Cornwall , country = England , coor = , administrative_staff = 2,647 , faculty = 3,145 (2020) , students = 23,613 (2018/19) , undergrad = 18,932 (2018/19) , postgrad = 4,681 (2018/19) , colours = Green and white , doctoral = , campus = Streatham – Penryn – St Luke's – , affiliations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermal Denticle
A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term ''scale'' derives from the Old French , meaning a shell pod or husk. Scales vary enormously in size, shape, structure, and extent, ranging from strong and rigid armour plates in fishes such as shrimpfishes and boxfishes, to microscopic or absent in fishes such as eels and anglerfishes. The morphology of a scale can be used to identify the species of fish it came from. Scales originated within the jawless ostracoderms, ancestors to all jawed fishes today. Most bony fishes are covered with the cycloid scales of salmon and carp, or the ctenoid scales of perch, or the ganoid scales of sturgeons and gars. Cartilaginous fishes (sharks and rays) are covered with placoid scales. Some species ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunicate
A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the 'seriation of the gill slits'. Some tunicates live as solitary individuals, but others replicate by budding and become colonies, each unit being known as a zooid. They are marine filter feeders with a water-filled, sac-like body structure and two tubular openings, known as siphons, through which they draw in and expel water. During their respiration and feeding, they take in water through the incurrent (or inhalant) siphon and expel the filtered water through the excurrent (or exhalant) siphon. Most adult tunicates are sessile, immobile and perman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sipunculid
The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of unsegmented marine annelid worms. The name ''Sipuncula'' is from the genus name ''Sipunculus'', and comes from the Latin ''siphunculus'' meaning a "small tube". Sipuncula was once considered a phylum, but was demoted to a class of Annelida, based on recent molecular work. Sipunculans vary in size but most species are under in length. The body is divided into an unsegmented, bulbous trunk and a narrower, anterior section, called the "introvert", which can be retracted into the trunk. The mouth is at the tip of the introvert and is surrounded in most groups by a ring of short tentacles. With no hard parts, the body is flexible and mobile. Although found in a range of habitats throughout the world's oceans, the majority of species live in shallow water habitats, burrowing under the surface of sandy and muddy substrates. Others live under stones, in rock crevic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
