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Trophic Effect
Trophic, from Ancient Greek τροφικός (''trophikos'') "pertaining to food or nourishment", may refer to: * Trophic cascade * Trophic coherence * Trophic egg * Trophic function * Trophic hormone * Trophic level index * Trophic level * Trophic mutualism * Trophic pyramid * Trophic species * Trophic state index See also * Food Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ... * Tropic (other) {{bca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Cascade
Trophic cascades are powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed. For example, a top-down cascade will occur if predators are effective enough in predation to reduce the abundance, or alter the behavior of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore). The trophic cascade is an ecological concept which has stimulated new research in many areas of ecology. For example, it can be important for understanding the knock-on effects of removing top predators from food webs, as humans have done in many places through hunting and fishing. A top-down cascade is a trophic cascade where the top consumer/predator controls the primary consumer population. In turn, the primary producer population thrives. The removal of the top predator can alter the food web dynamics. In this case, the primary consumers would overpopula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Coherence
Trophic coherence is a property of directed graphs (or directed networks). It is based on the concept of trophic levels used mainly in ecology, but which can be defined for directed networks in general and provides a measure of hierarchical structure among nodes. Trophic coherence is the tendency of nodes to fall into well-defined trophic levels. It has been related to several structural and dynamical properties of directed networks, including the prevalence of cycles and network motifs, ecological stability, intervality, and spreading processes like epidemics and neuronal avalanches. Definition Consider a directed network defined by the N\times N adjacency matrix A=(a_). Each node i can be assigned a trophic level s_i according to :: s_i=1+\frac\sum_j a_ s_j, where k_i^\text=\sum_j a_ is i's in-degree, and nodes with k_i^\text=0 (basal nodes) have s_i=1 by convention. Each edge has a ''trophic difference'' associated, defined as x_=s_i-s_j. The ''trophic coherence'' of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Egg
A trophic egg is an egg (biology), egg whose function is not reproduction but nutrition; in essence, the trophic egg serves as food for offspring hatched from viable eggs. In most species that produce them, a trophic egg is usually an Fertilization, unfertilised egg. The production of trophic eggs has been observed in a highly diverse range of species, including fish, amphibians, spiders and insects. The function is not limited to any particular level of Parental investment, parental care, but occurs in some Subsociality, sub-social species of insects, the spider ''Amaurobius_ferox, A. ferox'', and a few other species like the frogs ''Leptodactylus fallax'' and ''Oophaga'', and the catfish ''Bagrus meridionalis''. Parents of some species deliver trophic eggs directly to their offspring, whereas some other species simply produce the trophic eggs after laying the viable eggs; they then leave the trophic eggs where the viable offspring are likely to find them. The Lamniformes, mackerel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Function
A trophic function was first introduced in the differential equations of the Kolmogorov predator–prey model. It generalizes the linear case of predator–prey interaction firstly described by Volterra and Lotka in the Lotka–Volterra equation. A trophic function represents the consumption of prey assuming a given number of predators. The trophic function (also referred to as the functional response) was widely applied in chemical kinetics, biophysics, mathematical physics and economics. In economics, "predator" and "prey" become various economic parameters such as prices and outputs of goods in various linked sectors such as processing and supply. These relationships, in turn, were found to behave similarly to the magnitudes in chemical kinetics, where the molecular analogues of predators and prey react chemically with each other. These inter-disciplinary findings suggest the universal character of trophic functions and the predator–prey models in which they appear. They give ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Hormone
Trophic hormones are hormones of the anterior lobe of the pituitary. These hormones affect growth, function, or nutrition of other endocrine cells. Trophic hormones can be found in body systems including the endocrine, gastrointestinal, urinary, and nervous systems. The term ''trophic'' is from Ancient Greekτροφικός (''trophikós'') meaning "pertaining to food or nourishment", here used to mean "growth"; this is the same origin as ''atrophy.'' This should not be confused with ''tropic,'' as in the similar-sounding tropic hormone – the words and concepts are both unrelated. An example of this is thyroid-stimulating hormone stimulating the thyroid; excess thyroid-stimulating hormone can create a goitre. Trophic hormones from the anterior pituitary include: * Thyroid-stimulating hormone (TSH or thyrotropin) – stimulates the thyroid gland increasing the size and number of cells. * Adrenocorticotropic hormone (ACTH or corticotropin) – stimulates the adrenal cortex incr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Level Index
The trophic level index (TLI) is used in New Zealand as a measure of nutrient status of lakes. It is similar to the trophic state index but was proposed as alternative that suited New Zealand. The system uses four criteria, phosphorus and nitrogen concentrations, as well as visual clarity and algal biomass weighted equally. See also * Water pollution in New Zealand * Lakes of New Zealand *Environment of New Zealand The environment of New Zealand is characterised by an endemic flora and fauna which has evolved in near isolation from the rest of the world. The main islands of New Zealand span two biomes, Temperate climate, temperate and Subtropical climate ... External linksNew Zealand Ministry for the Environment- Trophic Level Index for lakesDefinitions of the 5 trophic states - Oligotrophic, Mesotrophic, Eutrophic, Supertrophic and Hypertrophic lakes References Water in New Zealand Water pollution {{NewZealand-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Level
The trophic level of an organism is the position it occupies in a food web. Within a food web, a food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it is from the start of the chain. A food web starts at trophic level 1 with primary producers such as plants, can move to herbivores at level 2, carnivores at level 3 or higher, and typically finish with apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a part of a wider food "web". Ecological communities with higher biodiversity form more complex trophic paths. The word ''trophic'' derives from the Ancient Greek, Greek wikt:τροφή, τροφή (trophē) referring to food or nourishment. History The concept of trophic level was developed by Raymond Lindeman (1942), based on the terminology of August Thienemann (1926): "producers", "consumers", and "reducers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Mutualism
Trophic mutualism is a key type of ecological mutualism. Specifically, "trophic mutualism" refers to the transfer of energy and nutrients between two species. This is also sometimes known as resource-to-resource mutualism. Trophic mutualism often occurs between an autotroph and a heterotroph. Although there are many examples of trophic mutualisms, the heterotroph is generally a fungus or bacteria. This mutualism can be both obligate and opportunistic. Examples *Rhizobia – Rhizobia are bacteria that conduct nitrogen fixation for legume plants. Specifically, these bacteria can be from genera ''Allorhizobium, Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium, or Sinorhizobium''.Vessey, K.J., K. Pawlowski, and B. Bergman, Root-based N2-fixing symbioses: Legumes, actinorhizal plants, Parasponiasp. and cycads. Plant and Soil 2005. 266(1-2): p. 205-230. In this mutualistic relationship, the bacteria grow on or within the root hair and penetrate into the plant tissuesTownsend, C.R. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
