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Food Chain
A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), detritivores (like earthworms or woodlice), or decomposer species (such as fungi or bacteria). A food chain also shows how organisms are related to each other by the food they eat. Each level of a food chain represents a different trophic level. A food chain differs from a food web because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. Food chains were first introduced by the Arab scientist and philosopher Al-Jahiz in the 10th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept. A common metric used to qua ...
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Food Chain
A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), detritivores (like earthworms or woodlice), or decomposer species (such as fungi or bacteria). A food chain also shows how organisms are related to each other by the food they eat. Each level of a food chain represents a different trophic level. A food chain differs from a food web because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. Food chains were first introduced by the Arab scientist and philosopher Al-Jahiz in the 10th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept. A common metric used to qua ...
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Al-Jahiz
Abū ʿUthman ʿAmr ibn Baḥr al-Kinānī al-Baṣrī ( ar, أبو عثمان عمرو بن بحر الكناني البصري), commonly known as al-Jāḥiẓ ( ar, links=no, الجاحظ, ''The Bug Eyed'', born 776 – died December 868/January 869) was a prose writer and author of works of literature, theology, zoology, and politico-religious polemics. He described himself as a member of the Arabian tribe Banu Kinanah. A thousand years before Darwin, Al-Jahiz came to the conclusion that there must be some mechanisms that influence the evolution of animals. He writes about three main mechanisms; the struggle for existence, the transformation of species into each other, and the environmental factors. He is therefore credited with outlining the principles of natural selection. Ibn al-Nadim lists nearly 140 titles attributed to Al-Jahiz, of which 75 are extant. The best known are ''Kitāb al-Ḥayawān'' (The book of Animals), a seven-part compendium on an array of subject ...
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Ecological Modeling
An ecosystem model is an abstract, usually mathematical, representation of an ecological system (ranging in scale from an individual population, to an ecological community, or even an entire biome), which is studied to better understand the real system. Using data gathered from the field, ecological relationships—such as the relation of sunlight and water availability to photosynthetic rate, or that between predator and prey populations—are derived, and these are combined to form ecosystem models. These model systems are then studied in order to make predictions about the dynamics of the real system. Often, the study of inaccuracies in the model (when compared to empirical observations) will lead to the generation of hypotheses about possible ecological relations that are not yet known or well understood. Models enable researchers to simulate large-scale experiments that would be too costly or unethical to perform on a real ecosystem. They also enable the simulation of ecol ...
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Ecological Monographs
The Ecological Society of America (ESA) is a professional organization of ecological scientists. Based in the United States and founded in 1915, ESA publications include peer-reviewed journals, newsletters, fact sheets, and teaching resources. It holds an annual meeting at different locations in the USA and Canada. In addition to its publications and annual meeting, ESA is engaged in public policy, science, education and diversity issues. ESA's 9,000 members are researchers, educators, natural resource managers, and students in over 90 countries. Members work on a wide range of topics, from agroecology to marine diversity and explore the relationships between organisms and their past, present, and future environments. The Society has over 20 topical sections and seven regional chapters. History The first discussions on the formation of the Society took place in 1914 in the lobby of the Hotel Walton in Philadelphia, Pennsylvania, at a meeting of animal and plant ecologists org ...
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Biological Organisation
Biological organisation is the hierarchy of complex biological structures and systems that define life using a reductionistic approach. The traditional hierarchy, as detailed below, extends from atoms to biospheres. The higher levels of this scheme are often referred to as an ecological organisation concept, or as the field, hierarchical ecology. Each level in the hierarchy represents an increase in organisational complexity, with each "object" being primarily composed of the previous level's basic unit. The basic principle behind the organisation is the concept of ''emergence''—the properties and functions found at a hierarchical level are not present and irrelevant at the lower levels. The biological organisation of life is a fundamental premise for numerous areas of scientific research, particularly in the medical sciences. Without this necessary degree of organisation, it would be much more difficult—and likely impossible—to apply the study of the effects of vario ...
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Continuous Variable
In mathematics and statistics, a quantitative variable may be continuous or discrete if they are typically obtained by ''measuring'' or '' counting'', respectively. If it can take on two particular real values such that it can also take on all real values between them (even values that are arbitrarily close together), the variable is continuous in that interval. If it can take on a value such that there is a non- infinitesimal gap on each side of it containing no values that the variable can take on, then it is discrete around that value. In some contexts a variable can be discrete in some ranges of the number line and continuous in others. Continuous variable A continuous variable is a variable whose value is obtained by measuring, i.e., one which can take on an uncountable set of values. For example, a variable over a non-empty range of the real numbers is continuous, if it can take on any value in that range. The reason is that any range of real numbers between a and ...
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Chesapeake Waterbird Food Web
Chesapeake often refers to: *Chesapeake people, a Native American tribe also known as the Chesepian * The Chesapeake, a.k.a. Chesapeake Bay *Delmarva Peninsula, also known as the Chesapeake Peninsula Chesapeake may also refer to: Populated places In Virginia * Chesapeake, Virginia, city * Chesapeake City, a.k.a. Phoebus, Virginia * Chesapeake, Northampton County, Virginia, unincorporated community * Chesapeake colony, a.k.a. Jamestown, Virginia In other U.S. states *Chesapeake, Indiana, defunct * Chesapeake, Missouri *Chesapeake, Ohio * Chesapeake, Tennessee, a neighborhood of Nashville *Chesapeake, West Virginia Schools * Chesapeake High School, Anne Arundel County, Maryland * Chesapeake High School, Baltimore, Maryland * Chesapeake College, public community college based in Wye Mills, Maryland Ships * United States lightship ''Chesapeake'' (LV-116), a lightvessel * USS ''Chesapeake'' (1799), an American frigate captured by HMS ''Shannon'' in 1813 * USS ''Patapsco'' ...
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Keystone Species
A keystone species is a species which has a disproportionately large effect on its natural environment relative to its abundance, a concept introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community. Without keystone species, the ecosystem would be dramatically different or cease to exist altogether. Some keystone species, such as the wolf, are also apex predators. The role that a keystone species plays in its ecosystem is analogous to the role of a keystone in an arch. While the keystone is under the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomas ...
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Decomposers
Decomposers are Organism, organisms that break down dead or decaying organisms; they carry out decomposition, a process possible by only certain kingdoms, such as fungi. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic material, organic substrates to get their energy, carbon and nutrients for growth and development. While the terms decomposer and detritivore are often interchangeably used, detritivores ''ingest'' and digest dead matter internally, while decomposers ''directly absorb'' nutrients through external chemical and biological processes. Thus, Invertebrate, invertebrates such as earthworms, woodlice, and sea cucumbers are technically detritivores, not decomposers, since they must ingest nutrients - they are unable to absorb them externally. Fungi The primary decomposer of litter in many ecosystems is fungi. Unlike bacteria, which are unicellular organisms and are decomposers as well, most saprotrophic fungi grow as a branching n ...
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Chemotrophs
A Chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic (chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototrophs, which use photons. Chemotrophs can be either autotrophic or heterotrophic. Chemotrophs can be found in areas where electron donors are present in high concentration, for instance around hydrothermal vents. Chemoautotroph Chemoautotrophs, in addition to deriving energy from chemical reactions, synthesize all necessary organic compounds from carbon dioxide. Chemoautotrophs can use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia or organic sources to produce energy. Most chemoautotrophs are extremophiles, bacteria or archaea that live in hostile environments (such as deep sea vents) and are the primary producers in such ecosystems. Chemoautotrophs generally fall into se ...
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Trophic Levels
The trophic level of an organism is the position it occupies in 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 food "web". Ecological communities with higher biodiversity form more complex trophic paths. The word ''trophic'' derives from the Greek 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" (modified to "decomposers" by Lindeman). Overview The three basic ways in which or ...
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Autotrophs
An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", 3rd edition, W. H. Freeman. generally using energy from light (photosynthesis) or inorganic chemical reactions (chemosynthesis). They convert an abiotic source of energy (e.g. light) into energy stored in organic compounds, which can be used by other organisms (e.g. heterotrophs). Autotrophs do not need a living source of carbon or energy and are the producers in a food chain, such as plants on land or algae in water (in contrast to heterotrophs as consumers of autotrophs or other heterotrophs). Autotrophs can reduce carbon dioxide to make organic compounds for biosynthesis and as stored chemical fuel. Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. The primary p ...
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