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Pycnogonum Litorale
''Pycnogonum litorale'' is a marine arthropod in the family Pycnogonidae, the sea spiders. It is found in the northern Atlantic Ocean, the North Sea, the English Channel and the western Mediterranean Sea. Description ''Pycnogonum litorale'' has a head, a small slender prosome (thorax) and a tiny opisthosome (abdomen), the trunk being up to in length. The head bears two pairs of eyes and a long, tapering proboscis, and in males, a pair of slender curved appendages called ovigers, which are used in reproduction. The prosome consists of four segments, each bearing a pair of relatively long, robust walking legs which each have nine segments and terminate with a claw; the prosome is too small to house all the internal organs, so these extend into the limbs. The colour of this sea spider is somewhat variable, being yellowish, pale brown or reddish-brown. Males tend to be darker than females, individuals that have recently fed tend to be darker than those that have not, while those tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Strøm
Hans Strøm (25 January 1726 – 1 February 1797) was a Norwegian clergyman. He also became a prominent zoologist and naturalist. He is best associated with his topographical description of the traditional district of Sunnmøre. Life Hans Strøm was born at Borgund in Møre og Romsdal, Norway. His father was a clergyman and many other relatives of both his father and mother were ministers. He attended the Bergen Cathedral School. He was educated as a Lutheran clergyman and in 1745 took a theological degree at the University of Copenhagen. Then he worked from 1750 to 1764 as chaplain in Borgund. In 1764 he became parish priest, first in Volda where he served until 1779, when he went to Eiker where he served as Vicar for 18 years. He died at Hokksund in Øvre Eiker in Buskerud. Topography Strøm is particularly known as a topographer, and especially for the model physical and economic description he gave of Søndmør's bailiff's office (1762–69), also called Søndmør ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beadlet Anemone
The beadlet anemone (''Actinia equina'') is a common sea anemone found on rocky shores around all coasts of the British Isles. Its range extends to the rest of Western Europe and the Mediterranean Sea, and along the Atlantic coast of Africa as far south as South Africa. ''Actinia equina'' can be found both in exposed and sheltered situations. It is highly adapted to the intertidal zone as it can tolerate both high temperatures and desiccation. The anemone may also be found in regions of variable salinity such as estuaries. Beadlet anemones can live in solitary or in aggregations. Solitary beadlet anemones are found to be larger-sized than those that form clustered aggregation. Furthermore, larger sea anemones were found submerged in low tide, where they have greater access to food resources and are less subjected to harsh environmental exposures. The size of beadlet anemones may be connected to their physiological adaptation in regards to limited food resources and withstanding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insects, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Animals can be divided into species that undergo complete metamorphosis (" holometaboly"), incomplete metamorphosis ("hemimetaboly"), or no metamorphosis (" ametaboly"). Scientific usage of the term is technically precise, and it is not applied to general aspects of cell growth, including rapid growth spurts. Generally organisms with a larva stage undergo metamorphosis, and during metamorphosis the organism loses larval characteristics. References to "metamorphosis" in mammals are imprecise and only colloquial, but historically idealist ideas of transformation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecdysis
Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnants of the old, empty exoskeleton are called exuviae. After moulting, an arthropod is described as ''teneral'', a ''callow''; it is "fresh", pale and soft-bodied. Within one or two hours, the cuticle hardens and darkens following a tanning process analogous to the production of leather. During this short phase the animal expands, since growth is otherwise constrained by the rigidity of the exoskeleton. Growth of the limbs and other parts normally covered by the hard exoskeleton is achieved by transfer of body fluids from soft parts before the new skin hardens. A spider with a small abdomen may be undernourished but more probably has recently undergone ecdysis. Some arthropods, especially large insects with tracheal respiration, expand thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
20-Hydroxyecdysone
20-Hydroxyecdysone (ecdysterone or 20E) is a naturally occurring ecdysteroid hormone which controls the ecdysis (moulting) and metamorphosis of arthropods. It is therefore one of the most common moulting hormones in insects, crabs, etc. It is also a phytoecdysteroid produced by various plants, including ''Cyanotis vaga'', ''Ajuga turkestanica'' and ''Rhaponticum carthamoides'' where its purpose is presumably to disrupt the development and reproduction of insect pests. In arthropods, 20-hydroxyecdysone acts through the ecdysone receptor. Although mammals lack this receptor, 20-hydroxyecdysone may affect mammalian (including human) biological systems ''in vitro'', but there is uncertainty whether any ''in vivo'' or physiological effects occur. 20-Hydroxyecdysone is an ingredient of some supplements that aim to enhance physical performance. In humans, it is hypothesized to bind to the estrogen receptor beta (ERβ) protein-coding gene. Sources in arthropods The primary sources of 20-h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinus Maenas
''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab, or green shore crab. In North America and South Africa, it bears the name european green crab. ''C. maenas'' is a widespread invasive species, listed among the 100 "world's worst alien invasive species". It is native to the north-east Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America and both Atlantic and Pacific coasts of North America. It grows to a carapace width of , and feeds on a variety of mollusks, worms, and small crustaceans, potentially affecting a number of fisheries. Its successful dispersal has occurred by a variety of mechanisms, such as on ships' hulls, sea planes, packing materials, and bivalves moved for aquaculture. Description ''C. maenas'' has a carapace up to long and wide, but can be larger outside its native ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metridium Dianthus
''Metridium dianthus'' is a species of sea anemone in the family Metridiidae. It is found in the northern Atlantic Ocean (including the coasts of the British Isles) and in the northeast Pacific Ocean. There is also a record from South Africa, possible resulting from an introduction. Description This is the largest sea anemone in the northeastern Atlantic; the smooth column can be in height with a pedal disc wider than this. This form is known as "dianthus" and on a large specimen, the oral disc may have a plume of several thousand tentacles some across, often forming several lobes. A smaller form, found most often in brackish water, is known as "pallidus" and may have two hundred tentacles and be across. Distribution and habitat ''Metridium dianthus'' is an adaptable, circumboreal species in the Northern Hemisphere. In the eastern Atlantic, its range extends from the Kola Peninsula in northern Russia to the Bay of Biscay, in the western Atlantic from the Arctic Circle to Dela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calliactis Parasitica
''Calliactis parasitica'' is a species of sea anemone associated with hermit crabs. It lives in the eastern Atlantic Ocean and Mediterranean Sea at depths between the intertidal zone and . It is up to in size, with up to 700 tentacles, and is very variable in colour. The relationship between ''C. parasitica'' and the hermit crab is mutualistic: the sea anemone protects the hermit crab with its stings, and benefits from the food thrown up by the hermit crab's movements. Description ''Calliactis parasitica'' is up to tall, and wide, with the base of the column being slightly wider. The surface of the column is rough and leathery with a grainy appearance, but has no tubercles and is not divided into sections. It is variable in colouring, but is usually cream or buff in colour, with blotches and streaks of reddish or greyish brown, which tend to form vertical stripes. The basal disc is concave, and able to stick firmly to the substrate. Above this lies the limbus (the junction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snakelocks Anemone
The snakelocks anemone (''Anemonia viridis'') is a sea anemone found in the eastern Atlantic Ocean and the Mediterranean Sea. The latter population is however sometimes considered a separate species, the Mediterranean snakelocks anemone (''Anemonia sulcata''). The tentacles are usually a deep green colour with purple tips, the green colour is often attributed to the presence of symbiotic algae within the tentacles but is actually the result of the presence of Green Fluorescent Protein which is present in corals, sea anemones, and some other cnidarians. The anemone tissue contains a symbiotic algae called zooxanthellae, which is necessary for the long-term survival of the sea anemone. When the numbers of algae diminish the anemone may appear dull grey in colour. The algae need light to flourish, so Snakelocks Anemones will be found in the sunniest pools. On average the snakelock anemone is 8 cm wide. Reproduction Unlike other cnidarians, anemones (and other Anthozoa) entire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitism
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), Disease vector, vector-transmitted paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arthropod cuticle, cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an exoskeleton, external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior Organ (anatomy), organs; it has an open circulatory system. Like their exteriors, the internal or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
