Copyright © Philip M. Parker, INSEAD. Terms of Use.
| Domain | Definition |
Avian | The position in the food chain determined by the number of energy-transfer steps to that level (Ricklefs 1979:881). (references) |
Weather | A segment of the food chain in which all organisms obtain food and energy in, basically, the same manner (e.g., photosynthesis, herbivory, or carnivory) and in which all organisms are the same number of links from the photosynthetic segment. (references) |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
Wildlife biologists look at a natural "economy of energy instead of money, and one that ultimately rests upon solar power. When they look at an ecosystem there is always some foundational species that directly harvests energy from the sun, for example grass. Next comes along some sort of herbivore that eats the grass, such as the rabbit. Then comes along a carnivore that eats the rabbit, such as a bobcat.
There can be several intermediate links, which means that we can have another layer of predators on top, in this case we have mountain lions which sometimes eat bobcats." Very often this top predator is a keystone species since it affects most of the balances beneath. "Since each layer of this system relates to the one below it by absorbing a fraction of the energy it consumed, each one can be understood as resting on the one below---which is called a lower trophic level.
"Every time there is an exchange of energy between one trophic level and another, there is a quite significant loss due to the fundamental laws of thermodynamics. This means so many units of grass can only support a much smaller number of units of rabbits, who can only support a smaller group of bobcats, who can only support a smaller group of cougars. This is why trophic levels are usually portrayed as a triangle, one that places grass on the bottom and cougars on top---the top is always much smaller than the bottom." Each level implies a loss of energy and efficiency and less life that can be supported by the sun. [1]
Consumers feed on protoplasm produced from photosynthesis or on other organisms from higher levels. Consumers depends on producers for their energy and synthesis needs. For example, herbivores are primary consumers (and secondary producers). A carnivore that eats only herbivores is a secondary consumer and a tertiary producer.
Decomposers utilise energy from wastes or dead organisms, and so complete the cycle by returning nutrients to the soil or water, and carbon dioxide to the air and water. See water cycle for more on water's role.
In the ocean, phytoplankton is the primary producer (the first level in the food chain or the first trophic level).Phytoplankton converts inorganic carbon into protoplasm.
The amount of biomass produced for a given amount of solar energy is highest at the first level. Less biomass is produced at the second level, for some energy is lost during the conversion. The more trophic levels there are, the more energy is lost through conversion.
Humans are generally primary and secondary consumers, and thus represent usually second and third trophic levels. Most humans are omnivores, which means they consume both plants and animals. Less energy is required to support vegetarian human than omnivores ones, for there is a significant energy loss during the conversion of grain and vegetables in animal matter.
Reduction of habitat, hunting and fishing of some species to extinction or near extinction, eradication of insects and pollution, tend to tip the balance of biodiversity. Similarly, in-situ conservation areas need to be carefully designed to maintain a diverse and stable environnement for the extinct species to thrive.
Energy economy
Components of ecosystems
Ecosystems have four basic components:
Producers utilise energy from the sun and nutrients from the abiotic environment (carbon dioxide from the atmosphere or water, other nutrients from the soil or water) to develop by means of photosynthesis. Examples of producers are green plants (those with chlorophyl) and phytoplankton. Since they get their carbon from carbon dioxide rather than from organic carbon, they are called autotrophic organisms. See carbon cycle for more on carbon's role.Biomass production
Primary production is generation of biomass through photosynthesis.
The highest producers of biomass are
Others include
while lowest producers are deserts and frozen areass (less than 200 g/m2/yr of biomass).
Phytoplankton is consumed by microscopic animals called zooplankton (these are the second level in the food chain).
Zooplankton is consumed by Crustaceans (the third level in the food chain).
Fish eating crustaceans could constitute the fourth trophic level, while seals consuming the fishes are the fifth.
Trophic levels are very similar on land, with plants being the first trophic level, cows eating the grass being the second, and humans eating the cows being the third.Trophic levels and biodiversity
Each species in an ecosystem is affected by the other species in that ecosystem. There are very few single prey-single predator relationship. Most preys are consumed by more than one predator, and most predators have more than one prey. Their relationships are also influenced by other environmental factors.
biodiversity (seen along the specific diversity point of view) gives ecosystems stability. When consumers have several differents producers available for food, the disappearance of one is not likely to have a lot of impact. However, for a consumer which has only one or a few producer, a decrease in the producer population is likely to affected it strongly.See also
External links
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Trophic level."
Crosswords: TROPHIC LEVEL |
| English words defined with "TROPHIC LEVEL": trophic. (references) |
| Specialty definitions using "TROPHIC LEVEL": algae bloom, algal bloom ♦ energy flow ♦ water bloom. (references) |
| Language | Translations for "TROPHIC LEVEL"; alternative meanings/domain in parentheses. | ||||||||||||||||
Danish | dominanterne paa et givet trofisk niveau er almindeligvis de arter, som er de stoerste, de hyppigst forekommende eller de mest aktive (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active), de autotrofe organismer udgoer det foerste trofiske niveau d.v.s. det foerste led i foedekaeden (the autotrophic organisms constitute the first trophic level). (various references) | ||||||||||||||||
Dutch | dominant zijn in het algemeen de soorten die op hun trofisch niveau de grootste dichtheid, de grootste afmetingen of de grootste activiteit vertonen (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active), de autotrofe organismen staan op het laagste trofische niveau en vormen de eerste schakel in de voedselketen (the autotrophic organisms constitute the first trophic level). (various references) | ||||||||||||||||
French | les organismes autotrophes constituent le premier niveau trophique, c'est- -dire le premier maillon de la chaîne alimentaire (the autotrophic organisms constitute the first trophic level), d'une manière générale, les dominantes sont les espèces, qui dans leur niveau trophique sont les plus fréquentes, les plus grandes ou les plus actives (the dominants at any given trophic level are those species which are the largest). (various references) | ||||||||||||||||
German | Dominanten sind im allgemeinen die Arten, die auf ihrem trophischen Niveau - ihrer Nahrungsstufe - zahlenmaessig am staerksten vertreten, am groessten oder am aktivsten sind (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active), die autotrophen Organismen stellen das erste trophische Niveau - trophische Ebene - , d. h. das erste Glied der Nahrungskette dar (i. e. the first link in the food chain, the autotrophic organisms constitute the first trophic level). (various references) | ||||||||||||||||
Greek | σε γενικές γραμμές,σε κάθε τροφική βαθμίδα δεσπόζουν τα μεγαλύτερα,πολυαριθμότερα και πιο δραστήρια είδη (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active), οι αυτότροφοι οργανισμοί αποτελούν το πρώτο τροφικό επίπεδο,δηλαδή τον πρώτο κρίκο της τροφικής αλυσίδας (i. e. the first link in the food chain, the autotrophic organisms constitute the first trophic level). (various references) | ||||||||||||||||
Italian | in genere i dominanti sono le specie che, nel loro livello trofico, hanno una maggior densita', dimensioni o attivita' (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active), gli organismi autotrofi costituiscono il primo livello trofico, ossia il primo anello della catena alimentare (i. e. the first link in the food chain, the autotrophic organisms constitute the first trophic level). (various references) | ||||||||||||||||
Pig Latin | ophictray evellay os organismos autotróficos constituem o primeiro nível trófico,isto é,o primeiro elo da cadeia alimentar (i. e. the first link in the food chain, the autotrophic organisms constitute the first trophic level), duma maneira geral,as espécies dominantes num determinado nível trófico são aquelas que apresentam maiores dimensões,são mais abundantes ou mais activas (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active). (various references) los organismos autótrofos constituyen el primer nivel trófico, es decir el primer eslabón de la cadena alimentaria (i. e. the first link in the food chain, the autotrophic organisms constitute the first trophic level), de forma general, las dominantes son las especies que, en su nivel trófico, son las más frecuentes, las más grandes o las más activas (generally speaking, the dominants at any given trophic level are those species which are the largest, the most abundant or the most active). (various references) | ||||||||||||||||
Scrabble® Enable2K-Verified Anagrams | |
| Words within the letters "c-e-e-h-i-l-l-o-p-r-t-v" | |
-2 letters: helicopter. | |
-3 letters: covellite, overchill, plethoric. | |
-4 letters: chlorite, clothier, coverlet, helicopt, heliport, herpetic, hotelier, leprotic, lovelier, orective, petrolic, prechill, reclothe. | |
-5 letters: cheerio, chervil, cheviot, chiller, chortle, collier, coterie, coveter, elector, electro, erethic, etheric, evictor, eviller, helleri, heretic, hilltop, hoplite, overlet, overlie, overlit, overtip, peloric, perlite, petiole, philter, philtre, picotee, pitcher, poitrel, politer, potiche, prelect, prithee. | |
| Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro. | |
| 1. Crosswords 2. Translations: Modern 3. Anagrams 4. Bibliography |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
