|
Metaphoetesis
Metaphoetesis is an ecological term coined by G. E. Hutchinson, to denote a change in diet with a changing stage of the life cycle of an animal. This characteristic, exhibited by many species such as insects and fishes, is important in determining the length of a food chain, particularly in aquatic and amphibious environments. Smaller, i.e., younger specimens belong to foodchain links below the larger -older- specimens. The concept has been described by other authors using various terms such as "life history omnivory". For instance, lake trout, ''Salvelinus namaycush'' Walbaum, 1792 Salmonidae, a Holoarctic freshwater fish species, exhibit different growth patterns within a single lake at a given time and among ensembles of similar lake types. These growth patterns are related to the species' food habits, and have consequences in growth rate, age at maturity, etc. Small, fast-growing, precocious adult trouts are planktivores, and inhabit lakes that are devoid of fish prey, while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Chain
A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as earthworms and woodlice), or decomposer (such as fungi or bacteria). It is not the same as a food web. A food chain depicts relations between species based on what they consume for energy in trophic levels, and they are most commonly quantified in length: the number of links between a trophic consumer and the base of the chain. Food chain studies play an important role in many biological studies. Food chain stability is very important for the survival of most species. When only one element is removed from the food chain it can result in extinction or immense decreases of survival of a species. Many food chains and food webs contain a keystone species, a species that has a large impact on the surrounding environment and that can directly a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Trout
The lake trout (''Salvelinus namaycush'') is a freshwater Salvelinus, char living mainly in lakes in Northern North America. Other names for it include mackinaw, namaycush, lake char (or charr), touladi, togue, laker, and grey trout. In Lake Superior, it can also be variously known as siscowet, paperbelly and lean. The lake trout is prized both as a game fish and as a Fish as food, food fish. Those caught with dark coloration may be called ''mud hens''. Taxonomy and etymology It is the only member of the subgenus ''Cristovomer'', which is more derived than the subgenus ''Salvelinus#Taxonomy, Baione'' (the most Basal (phylogenetics), basal clade of ''Salvelinus'', containing the brook trout (''S. fontinalis'') and silver trout (''S. agasizii'')) but still basal to the other members of ''Salvelinus''. The binominal nomenclature, specific epithet ''namaycush'' derives from ''namekush'', a form of the word used in some inland Southern East Cree language, Southern East Cree commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonidae
Salmonidae (, ) is a family (biology), family of ray-finned fish, the only extant member of the suborder Salmonoidei, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), Salvelinus, char, Thymallus, graylings, freshwater whitefishes, taimens and lenoks, all coldwater fish, coldwater mid-trophic level, level predatory fish that inhabit the subarctic and cool temperate waters of the Northern Hemisphere. The Atlantic salmon (''Salmo salar''), whose Latin name became that of its genus ''Salmo'', is also the eponym of the family and order names. Salmonids have a relatively primitive appearance among teleost fish, with the pelvic fins being placed far back, and an adipose fin towards the rear of the back. They have slender bodies with rounded fish scale, scales and forked caudal fin, tail fins, and their fish jaw, mouths contain a si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holarctic Realm
The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical region (which covers most of North America), and Alfred Wallace's Palearctic zoogeographical region (which covers North Africa, and all of Eurasia except for Southeast Asia, the Indian subcontinent, the southern Arabian Peninsula). These regions are further subdivided into a variety of ecoregions. Many ecosystems and the animal and plant communities that depend on them extend across a number of continents and cover large portions of the Holarctic realm. This continuity is the result of those regions’ shared glacial history. Major ecosystems Within the Holarctic realm, there are a variety of ecosystems. The type of ecosystem found in a given area depends on its latitude and the local geography. In the far north, a band of Arctic tundra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planktivore
A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and in the past billion years; basking sharks and copepods are just two examples of giant and microscopic organisms that feed upon plankton. Planktivory can be an important mechanism of top-down control that contributes to trophic cascades in aquatic and marine systems. There is a tremendous diversity of feeding strategies and behaviors that planktivores utilize to capture prey. Some planktivores utilize tides and currents to migrate between estuaries and coastal waters; other aquatic planktivores reside in lakes or reservoirs where diverse assemblages of plankton are present, or migrate vertically in the water column searching for prey. Planktivore populations can impact the abundance and community composition of planktonic species through th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piscivore
A piscivore () is a carnivorous animal that primarily eats fish. Fish were the diet of early tetrapod evolution (via water-bound amphibians during the Devonian period); insectivory came next; then in time, the more terrestrially adapted reptiles and synapsids evolved herbivory. Almost all predatory fish (most sharks, tuna, billfishes, pikes etc.) are obligated piscivores. Some non-piscine aquatic animals, such as whales, sea lions, and crocodilians, are not completely piscivorous; often also preying on invertebrates, marine mammals, waterbirds and even wading land animals in addition to fish, while others, such as the bulldog bat and gharial, are strictly dependent on fish for food. Some creatures, including cnidarians, octopuses, squid, cetaceans, spiders, grizzly bears, jaguars, wolves, snakes, turtles and sea gulls, may have fish as significant if not dominant portions of their diets. Humans can live on fish-based diets, as can their carnivorous domesticated pets su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Rain
Acid rain is rain or any other form of Precipitation (meteorology), precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid rain has a pH level lower than this and ranges from 4–5 on average. The more acidic the acid rain is, the lower its pH is. Acid rain can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the Properties of water, water molecules in the atmosphere to produce acids. Acid rain has been shown to have adverse impacts on forests, Fresh water, freshwaters, soils, microbes, insects and aquatic life-forms. In ecosystems, persistent acid rain reduces tree bark durability, leaving flora more susceptible to environmental stressors such as drought, heat/cold and pest infestation. Acid rain is also capable of detriment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mysis Relicta
''Mysis relicta'' is a shrimp-like crustacean in the Mysida order, native to lakes of Northern Europe and to the brackish Baltic Sea. Appearance Mysis is a small, transparent shrimp-like crustacean, of less than 2.5 cm length. It has two pairs of relatively long antennae, associated with rounded antennal plates; large, stalked compound eyes; the thorax covered by a coat-like carapace; a muscular, cylindrical abdomen; and a tail fan featuring a telson with a v-shaped terminal cleft. Reproducing females bear a prominent brood pouch (marsupium) between their thoracal legs. The pleopods (abdominal legs) of Mysis are reduced, except for a specialized pair of mating legs in males. Distribution The distribution of ''Mysis relicta'' is restricted to previously glaciated regions in Northern Europe, including northwest Russia, Finland, Sweden, southeast Norway, and parts of Germany, Poland, and Lithuania. Previously ''M. relicta'' was treated as a circumpolar taxon also present ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mysis Salemaai
''Mysis salemaai'' is a shrimp-like crustacean in the Mysida order, inhabiting lakes of Ireland and South Scandinavia and brackish waters of the northern Baltic Sea. Appearance ''Mysis salemaai'' is a transparent shrimp-like crustacean, of less than length. It has two pairs of relatively long antennae, associated with rounded antennal plates; large, stalked compound eyes; the thorax covered by a coat-like carapace; a muscular, cylindrical abdomen; and a tail fan featuring a telson with a V-shaped terminal cleft. Reproducing females bear a prominent brood pouch (marsupium) between their legs. ''Mysis'' are often called opossum shrimp. Distribution ''Mysis salemaai'' is a North European species which lives both in fresh and brackish waters. It is found in ten lakes on the island of Ireland, including Lough Neagh, Lough Erne, Lough Corrib and Lough Ree. It is also found in several lakes of Southern Scandinavia, including Fureso in Denmark and the large lakes Vänern and Vätt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mysis Diluviana
''Mysis'' is a genus of mysid crustaceans in the family Mysidae, distributed mainly in the coastal zone of the Arctic and high boreal seas. Several species also inhabit northern freshwater lakes and the brackish Caspian Sea. Fifteen species are recognized. Body lengths range from . The freshwater taxa of the genus have been referred to as " glacial relicts", and they comprise four closely related species, most of which also live in brackish water. '' Mysis relicta'' is a freshwater species from boreal lakes of Northern Europe, also present in the Baltic Sea. ''Mysis salemaai'' is another North European and Baltic Sea taxon. ''Mysis segerstralei'' is a fresh- and brackish-water species of the Eurasian and North American Arctic and sub-Arctic. The North American lakes, including the Great Lakes, are inhabited by '' Mysis diluviana''. Various species of Mysis are found in lakes of the South Swedish highlands, like Lake Sommen, that were never connected to the sea or the Baltic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthopelagic
The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone. Being just above the ocean floor, the demersal zone is variable in depth and can be part of the photic zone where light can penetrate, and photosynthetic organisms grow, or the aphotic zone, which begins between depths of roughly and extends to the ocean depths, where no light penetrates. Fish The distinction between demersal species of fish and Pelagic fish, pelagic species is not always clear cut. The Atlantic cod (''Gadus morhua'') is a typical demersal fish, but can also be found in the open water column The (oceanic) water column is a concept used in oceanography to describe the physical (temperature, salinity, light penetration) and chemical ( pH, dissolved oxygen, nutrient salts) characteristics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthropods including decapods (shrimps, prawns, crabs, lobsters and crayfish), seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods (insects and entognathans) emerged deep in the Crustacean group, with the completed pan-group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans ( oligostracans and multicrustaceans). The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
