Staddon et al 2010
... unexplored. For example, weak flows of individuals between habitats may have significant impacts on population production and community stability (Loreau et al. 2003). From this perspective, a more complete understanding of the impacts of habitat fragmentation on ecosystems requires the study of the ...
... unexplored. For example, weak flows of individuals between habitats may have significant impacts on population production and community stability (Loreau et al. 2003). From this perspective, a more complete understanding of the impacts of habitat fragmentation on ecosystems requires the study of the ...
Chapter 50: An Introduction to Ecology and the Biosphere
... how both contribute to species diversity. 13) Distinguish between a food chain and a food web. 14) Summarize two hypotheses that explain why food chains are relatively short. 15) Explain how dominant and keystone species exert strong control on community structure. Describe an example of each. 16) D ...
... how both contribute to species diversity. 13) Distinguish between a food chain and a food web. 14) Summarize two hypotheses that explain why food chains are relatively short. 15) Explain how dominant and keystone species exert strong control on community structure. Describe an example of each. 16) D ...
A meso-predator release of stickleback promotes recruitment of
... We tested large-scale effects of a meso-predator release on the adjacent trophic levels, invertebrate grazer and algae assemblages, by manipulating stickleback abundances in enclosures. In order to approach an ecosystem-relevant scale, we set up four large enclosures of approximately 20 × 30 m (600 ...
... We tested large-scale effects of a meso-predator release on the adjacent trophic levels, invertebrate grazer and algae assemblages, by manipulating stickleback abundances in enclosures. In order to approach an ecosystem-relevant scale, we set up four large enclosures of approximately 20 × 30 m (600 ...
Cascading top-down effects of changing oceanic predator
... 1. Top-down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects of predator depletions, recoveries, and invasions could be significant, such effects had rarely been demonstrated until recently. 2. Here we synthesize the evid ...
... 1. Top-down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects of predator depletions, recoveries, and invasions could be significant, such effects had rarely been demonstrated until recently. 2. Here we synthesize the evid ...
- Wiley Online Library
... 1. Top-down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects of predator depletions, recoveries, and invasions could be significant, such effects had rarely been demonstrated until recently. 2. Here we synthesize the evid ...
... 1. Top-down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects of predator depletions, recoveries, and invasions could be significant, such effects had rarely been demonstrated until recently. 2. Here we synthesize the evid ...
student resources - Santa Ana Unified School District
... are constantly changing and are extremely susceptible to human impact. 3. Photosynthesis occurs in organelles called chloroplasts. 4. Cellular respiration creates oxygen for other organisms to use. 5. Autotrophs are organisms that are able to transform chemical energy from light energy. 6. 90% of en ...
... are constantly changing and are extremely susceptible to human impact. 3. Photosynthesis occurs in organelles called chloroplasts. 4. Cellular respiration creates oxygen for other organisms to use. 5. Autotrophs are organisms that are able to transform chemical energy from light energy. 6. 90% of en ...
Trophic network models explain instability of Early Triassic terrestrial
... to major top-down propagations of secondary extinctions ( Vermeij 2004), though the effects of top-down trophic cascades can be demographically significant (Myers et al. 2007). Third, the increasing human exploitation of species at lower trophic levels, our expanding control of photosynthetic resour ...
... to major top-down propagations of secondary extinctions ( Vermeij 2004), though the effects of top-down trophic cascades can be demographically significant (Myers et al. 2007). Third, the increasing human exploitation of species at lower trophic levels, our expanding control of photosynthetic resour ...
Effects of Risk Assessment and Energy Expenditure on the Foraging
... surrounding area, we may make squirrels expend more energy than normally required to obtain food. We hypothesize that if squirrels have to expend more energy than normal to acquire food, the GUD of that system will be higher than that of a normal energy expenditure system. This pattern should be obs ...
... surrounding area, we may make squirrels expend more energy than normally required to obtain food. We hypothesize that if squirrels have to expend more energy than normal to acquire food, the GUD of that system will be higher than that of a normal energy expenditure system. This pattern should be obs ...
The Bioaccumulation of Methylmercury in an Aquatic Ecosystem
... will see in Section 8 that the model is sensitive to them. Unfortunately, we have only rule-of-thumb estimates to guide choice of these parameters. We define the values of L and n, the constants representing loss in biomass due to predation, to be 0.5. This estimate was based on the assumption that ...
... will see in Section 8 that the model is sensitive to them. Unfortunately, we have only rule-of-thumb estimates to guide choice of these parameters. We define the values of L and n, the constants representing loss in biomass due to predation, to be 0.5. This estimate was based on the assumption that ...
Nerve activates contraction
... community as well as all the abiotic factors with which they interact. • The dynamics of an ecosystem involve two processes: energy flow and chemical cycling. • Ecosystem ecologists view ecosystems as energy machines and matter processors. • We can follow the transformation of energy by grouping the ...
... community as well as all the abiotic factors with which they interact. • The dynamics of an ecosystem involve two processes: energy flow and chemical cycling. • Ecosystem ecologists view ecosystems as energy machines and matter processors. • We can follow the transformation of energy by grouping the ...
Organisms and food webs in rock pools
... Differential susceptibility of organisms and populations to environmental stress influences the outcome of biological interactions and the structure of communities and ecosystems. In this thesis, the effects of environmental stress on organism, population and community levels were studied. ‘Die phys ...
... Differential susceptibility of organisms and populations to environmental stress influences the outcome of biological interactions and the structure of communities and ecosystems. In this thesis, the effects of environmental stress on organism, population and community levels were studied. ‘Die phys ...
Ecosystem Impact of the Decline of Large Whales in the North Pacific
... similar effects (Jackson et al. 2001). For marine vertebrates, overharvesting is the main driver of ecological extinction, and the expansion of fishing fleets into the open ocean has precipitated rapid declines in pelagic apex predators such as whales (Baker and Clapham 2002), sharks (Baum et al. 20 ...
... similar effects (Jackson et al. 2001). For marine vertebrates, overharvesting is the main driver of ecological extinction, and the expansion of fishing fleets into the open ocean has precipitated rapid declines in pelagic apex predators such as whales (Baker and Clapham 2002), sharks (Baum et al. 20 ...
Darwin`s bark spider: giant prey in giant orb webs (Caerostris
... ‘‘rudimentary’’). The webs were almost symmetric with the ladder index of 0.78–1.49 (A 5 1.19 6 0.18) and hub displacement of 0.47–0.69 (A 5 0.59 6 0.05). Most (63%) webs did not contain kleptoparasitic spiders. Four (21%) webs contained one or two kleptoparasites (all Argyrodinae), whereas only thr ...
... ‘‘rudimentary’’). The webs were almost symmetric with the ladder index of 0.78–1.49 (A 5 1.19 6 0.18) and hub displacement of 0.47–0.69 (A 5 0.59 6 0.05). Most (63%) webs did not contain kleptoparasitic spiders. Four (21%) webs contained one or two kleptoparasites (all Argyrodinae), whereas only thr ...
Mixotrophs combine resource use to outcompete specialists
... The majority of organisms can be grouped into those relying solely on photosynthesis (phototrophy) or those relying solely on the assimilation of organic substances (heterotrophy) to meet their requirements for energy and carbon. However, a special life history trait exists in which organisms combin ...
... The majority of organisms can be grouped into those relying solely on photosynthesis (phototrophy) or those relying solely on the assimilation of organic substances (heterotrophy) to meet their requirements for energy and carbon. However, a special life history trait exists in which organisms combin ...
parasitism food web module
... Here, Ni is population density of species i. The first term in Eq. 1, r1N1, is the population growth of the basal species ...
... Here, Ni is population density of species i. The first term in Eq. 1, r1N1, is the population growth of the basal species ...
Local feeding specialization by badgers
... 1988). Thus, allopatric populations of generalist species (those whose diet varies according to prey availability) may specialize by means of behavioural responses to the different prey abundance they experience. Change in consumer behaviour is one of the factors invoked by Fox and Morrow (1981) to ...
... 1988). Thus, allopatric populations of generalist species (those whose diet varies according to prey availability) may specialize by means of behavioural responses to the different prey abundance they experience. Change in consumer behaviour is one of the factors invoked by Fox and Morrow (1981) to ...
Adaptation, density dependence and the responses of trophic level
... The responses of abundances to the extrinsic per capita mortality rates are obtained by differentiating the equilibrium conditions for equations (1a–d) with respect to each of the di. The resulting formulae can be simplified somewhat by assuming that the equilibrium of the system is locally stable. ...
... The responses of abundances to the extrinsic per capita mortality rates are obtained by differentiating the equilibrium conditions for equations (1a–d) with respect to each of the di. The resulting formulae can be simplified somewhat by assuming that the equilibrium of the system is locally stable. ...
ZAP! - Fort Wayne Children`s Zoo
... combined with water and carbon dioxide during photosynthesis, is converted into sugar. Plants form the base of an energy or food pyramid and are therefore called primary producers. Primary consumers (herbivores) make use of the energy trapped inside plants, but a great deal of plant matter must be e ...
... combined with water and carbon dioxide during photosynthesis, is converted into sugar. Plants form the base of an energy or food pyramid and are therefore called primary producers. Primary consumers (herbivores) make use of the energy trapped inside plants, but a great deal of plant matter must be e ...
effects of top predator species on direct
... exhibited different hunting behavior (i.e., sit-and-wait, sit-and-pursue, and active hunting) and occupied different locations within the vegetation canopy. These differences resulted in different direct effects on grasshopper prey. Grasshoppers demonstrated significant behavioral (diet) shifts in t ...
... exhibited different hunting behavior (i.e., sit-and-wait, sit-and-pursue, and active hunting) and occupied different locations within the vegetation canopy. These differences resulted in different direct effects on grasshopper prey. Grasshoppers demonstrated significant behavioral (diet) shifts in t ...
Phylogenetic signal in predator–prey body
... mass of both (Brose et al. 2006a). As a result, since interaction strength appears to scale with body-mass ratio in trophic interactions (Emmerson and Raffaelli 2004), the scaling of predator–prey interaction strengths should change at higher trophic levels, and with it the effects of interacting sp ...
... mass of both (Brose et al. 2006a). As a result, since interaction strength appears to scale with body-mass ratio in trophic interactions (Emmerson and Raffaelli 2004), the scaling of predator–prey interaction strengths should change at higher trophic levels, and with it the effects of interacting sp ...
Common large-scale responses to climate and fishing across
... a minimum/maximum autocorrelation factor analysis of biological indicators for each region revealed a common primary multivariate trend of a rapid change during the 1980s and early 1990s. There was a strong common pattern in the biological indicators responsible for the primary multivariate temporal ...
... a minimum/maximum autocorrelation factor analysis of biological indicators for each region revealed a common primary multivariate trend of a rapid change during the 1980s and early 1990s. There was a strong common pattern in the biological indicators responsible for the primary multivariate temporal ...
Pdf version - Université de Liège
... abundant in the Autumn and in the Winter, i.e. when P. oceanica sheds its leaves, than in the Spring and in the Summer. However, while these seasonal variations do have an influence on the number of invertebrates living in the litter, have virtually no effect on their diversity. There is another typ ...
... abundant in the Autumn and in the Winter, i.e. when P. oceanica sheds its leaves, than in the Spring and in the Summer. However, while these seasonal variations do have an influence on the number of invertebrates living in the litter, have virtually no effect on their diversity. There is another typ ...
Genetic variation, predator–prey interactions and food web structure
... One of the most important traits that explains ‘who eats whom’ in many food webs is body size [21]. Successful predation may largely depend on the body size ratio between the predator and the potential prey, predation being more likely to occur at larger ratios [41]. This causes diets to be highly n ...
... One of the most important traits that explains ‘who eats whom’ in many food webs is body size [21]. Successful predation may largely depend on the body size ratio between the predator and the potential prey, predation being more likely to occur at larger ratios [41]. This causes diets to be highly n ...
Food web
A food web (or food cycle) is the natural interconnection of food chains and generally a graphical representation (usually an image) of what-eats-what in an ecological community. Another name for food web is a consumer-resource system. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs. To maintain their bodies, grow, develop, and to reproduce, autotrophs produce organic matter from inorganic substances, including both minerals and gases such as carbon dioxide. These chemical reactions require energy, which mainly comes from the sun and largely by photosynthesis, although a very small amount comes from hydrothermal vents and hot springs. A gradient exists between trophic levels running from complete autotrophs that obtain their sole source of carbon from the atmosphere, to mixotrophs (such as carnivorous plants) that are autotrophic organisms that partially obtain organic matter from sources other than the atmosphere, and complete heterotrophs that must feed to obtain organic matter. The linkages in a food web illustrate the feeding pathways, such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs. The food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange. There are different kinds of feeding relations that can be roughly divided into herbivory, carnivory, scavenging and parasitism. Some of the organic matter eaten by heterotrophs, such as sugars, provides energy. Autotrophs and heterotrophs come in all sizes, from microscopic to many tonnes - from cyanobacteria to giant redwoods, and from viruses and bdellovibrio to blue whales.Charles Elton pioneered the concept of food cycles, food chains, and food size in his classical 1927 book ""Animal Ecology""; Elton's 'food cycle' was replaced by 'food web' in a subsequent ecological text. Elton organized species into functional groups, which was the basis for Raymond Lindeman's classic and landmark paper in 1942 on trophic dynamics. Lindeman emphasized the important role of decomposer organisms in a trophic system of classification. The notion of a food web has a historical foothold in the writings of Charles Darwin and his terminology, including an ""entangled bank"", ""web of life"", ""web of complex relations"", and in reference to the decomposition actions of earthworms he talked about ""the continued movement of the particles of earth"". Even earlier, in 1768 John Bruckner described nature as ""one continued web of life"".Food webs are limited representations of real ecosystems as they necessarily aggregate many species into trophic species, which are functional groups of species that have the same predators and prey in a food web. Ecologists use these simplifications in quantitative (or mathematical) models of trophic or consumer-resource systems dynamics. Using these models they can measure and test for generalized patterns in the structure of real food web networks. Ecologists have identified non-random properties in the topographic structure of food webs. Published examples that are used in meta analysis are of variable quality with omissions. However, the number of empirical studies on community webs is on the rise and the mathematical treatment of food webs using network theory had identified patterns that are common to all. Scaling laws, for example, predict a relationship between the topology of food web predator-prey linkages and levels of species richness.