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Ephippial
Ephippia (singular: ephippium) are winter or dry-season eggs of the various species of small crustacean in the order Cladocera (within the Branchiopoda); they are provided with an extra shell layer, which preserves and protects the resting stages inside from harsh environmental conditions until the more favorable times, such as spring, when the reproductive cycle is able to take place once again. Ephippia are part of the back of a mother carrying them until they are fully developed. After molting, the ephippium stays in the water, or in the soil of dried puddles, small ponds, and vernal pools. The resting stages are often called eggs, but are in fact embryos with arrested development. Ephippia can rest for many years before the embryo resumes development upon an appropriate hatching stimulus. See also * ''Bythotrephes longimanus'' (invasive species) * ''Cercopagis pengoi'' (invasive species) * ''Daphnia ** ''Daphnia longispina'' ** ''Daphnia lumholtzi'' (invasive species) * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnid GLERL 1
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladocera
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orchidaceae
Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering plants. The Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. (See ''External links'' below). The determination of which family is larger is still under debate, because verified data on the members of such enormous families are continually in flux. Regardless, the number of orchid species is nearly equal to the number of bony fishes, more than twice the number of bird species, and about four times the number of mammal species. The family encompasses about 6–11% of all species of seed plants. The largest genera are ''Bulbophyllum'' (2,000 species), ''Epidendrum'' (1,500 species), ''Dendrobium'' (1,400 species) and ''Pleurothallis'' (1,000 species). It also includes ''Vanilla'' (the genus of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnia Longispina
''Daphnia longispina'' is a planktonic crustacean of the family Daphniidae, a cladoceran freshwater water flea. It is native to Eurasia. ''D. longispina'' is similar in size and sometimes confused with the often sympatric '' D. pulex'' (a very common species), but much smaller than '' D. magna''. ''D. longispina'' is found in a wide range of standing freshwater bodies from small, ephemeral rock-pools to large lakes. Life history Like all ''Daphnia'' species, ''D. longispina'' is a filter feeder, collecting particles of about 2 to 40 µm suspended in the water. The main food are green algae. At 20 °C maturity is reached within about 6 to 12 days, followed by a period of regular reproduction in about 3-4 day intervals. ''D. longispina'' reproduces either asexually (''parthenogenesis'') or sexually. For the later, females need to produce sons asexually. The same or other females can switch at any moment from asexual to sexual reproduction, but producing haploid eggs, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books by decree in 1586, it is the second oldest university press after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics known as the Delegates of the Press, who are appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 500 years, OUP has primarily focused on the publication of pedagogical texts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moina
''Moina'' is a genus of crustaceans within the family Moinidae. The genus was first described by W. Baird in 1850. They are referred to as water fleas, but are related to the much larger ''Daphnia magna'' and the larger ''Daphnia pulex''. This genus demonstrates the ability to survive in waters containing low oxygen levels, high salinity, and other impurities, including salt pans, and commonly eutrophication. An example of such an extreme habitat is the highly saline Makgadikgadi Pans of Botswana, which supports prolific numbers of '' Moina belli''. The ''Moina'' are known to be found in various types of bodies of water in Eurasia where new found research indicates that there is an increased presence of biodiversity in regions of Northern Eurasia, Japan and China. There is an increase of new phylogroups found in Northern Eurasia, an increase of 4 new ''Moina'' species in Japan and an increase of five new lineages in China. Species ''Moina'' contains these species: * '' M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnia Pulex
''Daphnia pulex'' is the most common species of water flea. It has a cosmopolitan distribution: the species is found throughout the Americas, Europe, and Australia. It is a model species, and was the first crustacean to have its genome sequenced. Description ''D. pulex'' is an arthropod whose body segments are difficult to distinguish. It can only be recognised by its appendages (only ever one pair per segment), and by studying its internal anatomy. The head is distinct and is made up of six segments, which are fused together even as an embryo. It bears the mouthparts, and two pairs of antennae, the second pair of which is enlarged into powerful organs used for swimming. No clear division is seen between the thorax and abdomen, which collectively bear five pairs of appendages. The shell surrounding the animal extends posteriorly into a spine. Like most other ''Daphnia'' species, ''D. pulex'' reproduces by cyclical parthenogenesis, alternating between sexual and asexual reprodu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnia Magna
''Daphnia magna'' is a small planktonic crustacean (adult length 1.5–5.0 mm) that belongs to the subclass Phyllopoda. Description ''D. magna'' is a typical water flea of the genus ''Daphnia''. The females reach up to 5 mm in size, the males about 2 mm, thus they are among the largest species in the genus. The body is protected by a translucent carapace made of chitin, a transparent polysaccharide. It has a ventral opening and five pairs of thoracic limbs, used to help the filtering process. Spike rows run along the back of the carapace. The intestine is hook-shaped and has two digestive ceca. The head has two antennae and a large compound eye. Adult females can be distinguished from those of otherwise similar species such as '' D. pulex'' by the absence of a comb on the abdominal claw and the presence of two distinct combs on the abdomen. The males are smaller than the females and have larger first antennas, a diagnostic feature that distinguishes them from s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnia Lumholtzi
''Daphnia lumholtzi'' is a species of small, invasive water fleas that originates in the tropical and subtropical lakes of Africa, Asia, and Australia. As an invasive species, ''Daphnia lumholtzi'' disrupts aquatic habitats by spreading throughout the warmer waters of lakes and reservoirs. Description ''Daphnia lumholtzi'' is a small crustacean that is 2–3 mm in length. It has a large helmet and a long tailspine, usually longer than the length of its body, that fluctuates in size. Its body structure is arched, extending to a sharp point. There are roughly 10 prominent spines on the margin of the abdominal shield covering. Ecology Temperature ''Daphnia lumholtzi'' is typically found in the warm, shallow regions of bodies of water with larger surface areas. While most species of ''Daphnia'' see high mortality at temperatures greater than 25 °C, ''D. lumholtzi'' individuals can survive and reproduce at temperatures up to 30 °C, with a thermal optimum occurring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercopagis Pengoi
''Cercopagis pengoi'', or the fishhook waterflea, is a species of planktonic cladoceran crustaceans that is native in the brackish fringes of the Black Sea and the Caspian Sea. In recent decades it has spread as an invasive species to some freshwater waterways and reservoirs of Eastern Europe and to the brackish Baltic Sea. Further it was introduced in ballast water to the Great Lakes of North America and a number of adjacent lakes, and has become a pest classified among the 100 worst invasive species of the world. ''Cercopagis pengoi'' is a predatory cladoceran and thus a competitor to other planktivorous invertebrates and smaller fishes. On the other hand, it has provided a new food source for planktivorous fishes. It is also a nuisance to fisheries as it tends to clog nets and fishing gear.Birnbaum, C. (2006)''Cercopagis pengoi''. NOBANIS – Invasive Alien Species Fact Sheet. Description The length of ''Cercopagis pengoi'' body is 1–3 mm, but with the tail included ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnia
''Daphnia'' is a genus of small planktonic crustaceans, in length. ''Daphnia'' are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembles the movements of fleas. ''Daphnia'' spp. live in various aquatic environments ranging from acidic swamps to freshwater lakes and ponds. The two most commonly found species of ''Daphnia'' are '' D. pulex'' (small and most common) and '' D. magna'' (large). They are often associated with a related genus in the order Cladocera: ''Moina'', which is in the Moinidae family instead of the Daphniidae, and is much smaller than ''D. pulex'' (roughly half the maximum length). Appearance and characteristics The body of a ''Daphnia'' species is usually long, and is divided into segments, although this division is not visible. The head is fused, and is generally bent down towards the body with a visible notch separating the two. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bythotrephes Longimanus
''Bythotrephes longimanus'' (also ''Bythotrephes cederstroemi''), or the spiny water flea, is a planktonic crustacean less than long. It is native to fresh waters of Northern Europe and Asia, but has been accidentally introduced and widely distributed in the Great Lakes area of North America since the 1980s.''Bythotrephes longimanus'' USGS NAS – Nonindigenous Aquatic Species ''Bythotrephes'' is typified by a long abdominal spine with several barbs which protect it from predators. Description and taxonomy ''Bythotrephes longimanus'' is a crustacean (water flea) recognizable with its straight tail spine averaging about 70% of its length. Adult individuals have thre ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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