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Network Ecology
An ecological network is a representation of the biotic interactions in an ecosystem, in which species (nodes) are connected by pairwise interactions (links). These interactions can be trophic or symbiotic. Ecological networks are used to describe and compare the structures of real ecosystems, while network models are used to investigate the effects of network structure on properties such as ecosystem stability. Properties Historically, research into ecological networks developed from descriptions of trophic relationships in aquatic food webs; however, recent work has expanded to look at other food webs as well as webs of mutualists. Results of this work have identified several important properties of ecological networks. Complexity (linkage density): the average number of links per species. Explaining the observed high levels of complexity in ecosystems has been one of the main challenges and motivations for ecological network analysis, since early theory predicted that com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Interaction
In ecology, a biological interaction is the effect that a pair of organisms living together in a community have on each other. They can be either of the same species (intraspecific interactions), or of different species (interspecific interactions). These effects may be short-term, or long-term, both often strongly influence the adaptation and evolution of the species involved. Biological interactions range from mutualism, beneficial to both partners, to competition, harmful to both partners. Interactions can be direct when physical contact is established or indirect, through intermediaries such as shared resources, territories, ecological services, metabolic waste, toxins or growth inhibitors. This type of relationship can be shown by net effect based on individual effects on both organisms arising out of relationship. Several recent studies have suggested non-trophic species interactions such as habitat modification and mutualisms can be important determinants of food web struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecological Niche
In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of Resource (biology), resources and competitors (for example, by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (for example, limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey). "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another [and] the relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts". See also Chapter 2: Concepts of niches, pp. 7 ''ff'' A Grinnellian niche is determined by the habitat in which a species lives and its accompanying Behavioral ecology, behavioral adaptations. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecology
Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere levels. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and is the study of abundance (ecology), abundance, biomass (ecology), biomass, and distribution of organisms in the context of the environment. It encompasses life processes, interactions, and adaptations; movement of materials and energy through living communities; ecological succession, successional development of ecosystems; cooperation, competition, and predation within and between species; and patterns of biodiversity and its effect on ecosystem processes. Ecology has practical applications in fields such as conservation biology, wetland management, natural resource m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycle (graph Theory)
In graph theory, a cycle in a graph is a non-empty trail in which only the first and last vertices are equal. A directed cycle in a directed graph is a non-empty directed trail in which only the first and last vertices are equal. A graph without cycles is called an ''acyclic graph''. A directed graph without directed cycles is called a '' directed acyclic graph''. A connected graph without cycles is called a ''tree''. Definitions Circuit and cycle * A circuit is a non-empty trail in which the first and last vertices are equal (''closed trail''). : Let be a graph. A circuit is a non-empty trail with a vertex sequence . * A cycle or simple circuit is a circuit in which only the first and last vertices are equal. * ''n'' is called the length of the circuit resp. length of the cycle. Directed circuit and directed cycle * A directed circuit is a non-empty directed trail in which the first and last vertices are equal (''closed directed trail''). : Let be a directed grap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecological Stability
In ecology, an ecosystem is said to possess ecological stability (or equilibrium) if it is capable of returning to its equilibrium state after a perturbation (a capacity known as Ecological resilience, resilience) or does not experience unexpected large changes in its characteristics across time. Although the terms community stability and ecological stability are sometimes used interchangeably, community stability refers only to the characteristics of Community (ecology), communities. It is possible for an ecosystem or a community to be stable in some of their properties and unstable in others. For example, a vegetation community in response to a drought might conserve Biomass (ecology), biomass but lose biodiversity. Stable ecological systems abound in nature, and the scientific literature has documented them to a great extent. Scientific studies mainly describe grassland plant communities and microbial communities. Nevertheless, it is important to mention that not every communi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proc Natl Acad Sci USA
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Sciences, published since 1915, and publishes original research, scientific reviews, commentaries, and letters. According to ''Journal Citation Reports'', the journal has a 2022 impact factor of 9.4. ''PNAS'' is the second most cited scientific journal, with more than 1.9 million cumulative citations from 2008 to 2018. In the past, ''PNAS'' has been described variously as "prestigious", "sedate", "renowned" and "high impact". ''PNAS'' is a delayed open-access journal, with an embargo period of six months that can be bypassed for an author fee ( hybrid open access). Since September 2017, open access articles are published under a Creative Commons license. Since January 2019, ''PNAS'' has been online-only, although print issues are available on ... [...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] |
Intraguild Predation
Intraguild predation, or IGP, is the killing and sometimes eating of a potential competitor of a different species. This interaction represents a combination of predation and competition, because both species rely on the same prey resources and also benefit from preying upon one another. Intraguild predation is common in nature and can be asymmetrical, in which one species feeds upon the other, or symmetrical, in which both species prey upon each other. Because the dominant intraguild predator gains the dual benefits of feeding and eliminating a potential competitor, IGP interactions can have considerable effects on the structure of ecological communities. Types Intraguild predation can be classified as asymmetrical or symmetrical. In asymmetrical interactions one species consistently preys upon the other, while in symmetrical interactions both species prey equally upon each other. Intraguild predation can also be age structured, in which case the vulnerability of a species to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Competition
Competition is an interaction between organisms or species in which both require one or more resources that are in limited supply (such as food, water, or territory). Competition lowers the fitness of both organisms involved since the presence of one of the organisms always reduces the amount of the resource available to the other. In the study of community ecology, competition within and between members of a species is an important biological interaction. Competition is one of many interacting biotic and abiotic factors that affect community structure, species diversity, and population dynamics (shifts in a population over time). There are three major mechanisms of competition: interference, exploitation, and apparent competition (in order from most direct to least direct). Interference and exploitation competition can be classed as "real" forms of competition, while apparent competition is not, as organisms do not share a resource, but instead share a predator. Competition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Chains
''Food Chains'' is a 2014 American documentary film about agricultural labor in the United States directed by Sanjay Rawal. It was the Recipient of the 2015 James Beard Foundation Award for Special/Documentary.James Beard Foundation/ The 2015 Book, Broadcast, and Journalism Awards: Complete Winner Recap ''James Beard Foundation'', April 24, 2015 Summary In Immokalee, Florida, migrant farmworkers pick fruits and vegetables that are sold to large US food wholesalers.Dave McNaryEva Longoria’s ‘Food Chains’ Documentary Getting U.S. Distribution ''Variety (magazine), Variety'', March 31, 2014 However, their working conditions are shown to be less than favorable. As a result, they form the Coalition of Immokalee Workers (CIW) to raise awareness and improve their circumstances.Frank Scheck'Food Chains': Film Review ''The Hollywood Reporter'', November 24, 2014 Specifically, they go on a hunger strike to pressure Publix, a Florida-based food wholesaler, to pay them one penny more per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Motif
Network motifs are recurrent and statistically significant subgraphs or patterns of a larger graph. All networks, including biological networks, social networks, technological networks (e.g., computer networks and electrical circuits) and more, can be represented as graphs, which include a wide variety of subgraphs. Network motifs are sub-graphs that repeat themselves in a specific network or even among various networks. Each of these sub-graphs, defined by a particular pattern of interactions between vertices, may reflect a framework in which particular functions are achieved efficiently. Indeed, motifs are of notable importance largely because they may reflect functional properties. They have recently gathered much attention as a useful concept to uncover structural design principles of complex networks. Although network motifs may provide a deep insight into the network's functional abilities, their detection is computationally challenging. Definitions Let and be two gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecology (journal)
''Ecology'' is a scientific journal that publishes research and synthesizes papers in the field of ecology. It was founded in 1920 as the continuation of ''Plant World'', and is published by the Ecological Society of America. According to the ''Journal Citation Reports,'' it is currently ranked 15th out of 136 journals in the Ecology Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ... category. References External links * Ecology journals English-language journals Academic journals established in 1920 {{ecology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
