...larvae are eaten by mice d) there are “bumper years” of lyme disease e) ticks like to feed on human blood Answer: a 5) The Environmental Science textbook outlines the relatively simple food chain that exists in hot springs such as in Yellowstone National Park, including the following organisms: (A) herbivorous flies (B) carnivorous flies (C) decomposers (D) photosynthetic bacteria What would be the correct order of these organisms from lowest trophic level to highest trophic level: a) C, A, B, D b) B, A, D, C c) D, A, B, C d) B, A, C, D e) C, D, A, B Answer: c 6) Which of the following is an example of three different species on three different trophic levels, listed from lowest level to highest: a) shrubs, trees, giraffes b) humans, cows, grass c) sharks, herbivorous fish, carnivorous fish d) moss, reindeer, wolves e) dirt, corn, humans Answer: d 7) The most basic processes in an ecosystem are: a) photosynthesis and respiration b) transport and storage of food c) trophic chains and storage of food d) flow of energy and cycling of chemical elements e) waste decomposition and cycling of energy...
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...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...
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...throughout an ecosystem. Each and every one of the overlapping, and organized food chains in the same ecosystem create a food web. "A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom"( J. Duffy, 2013 ). Trophic levels consist of a group of organisms in the food webs. Also, this trophic levels are divided into three levels and this levels are decomposers, consumers, and producers. The first trophic level is known as Producers. Also, they create their food and they don't turn to other organism, and they also called autotrophs. Normally autotrophs create food using a process known as photosynthesis, and that create a nutrient known as glucose, and these consist of water , carbon dioxide, and sunlight. There are different types of autotroph but plants are the most known type. One larger plant that's known as seaweed is a autotroph. Also, tiny organisms living in the deep-sea called Phytoplankton, are also autotrophs. There are various bacteria that are autotrophs. Example, in a lively volcanoes exist bacteria and they use sulfur to put together its own food. This procedure is known as chemosynthesis. The following trophic levels consist of organism that consume producers. This animals or creatures are known as consumers. Main consumers are known to be herbivores. Herbivores consume plant life, seaweed, and others producers. Deer, cows, and even elephants are herbivores living in a ecosystem of grassland...
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...food chains a food network or food web. Another important connection in this cycle is the process of energy passing from one organism to the next. This process is the energy flow, and the food web illustrates the energy flow among the organisms in the food chain for the Mojave Desert ecosystem. The Pathways of Energy Flow Scientists identify food chains and food webs as the pathways that energy and matter pass from each link in the chain beginning with the producers and distributing out to the consumers. As Simon, Reece, and Dickey (2010) note, “the feeding relationships among the various species in a community are referred to as its trophic structure. A community’s trophic structure determines the passage of energy and nutrients from plants and other photosynthetic organisms to herbivores and then to predators” (p. 432). The trophic level of...
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...ecosystem, all the food chains consisted in a food web. Those that are living in an ecosystem is part of more than one food chain. As the process moves on through the ecosystem, each food chain is one possible path that energy and nutrients may take (Mader, 1996). Indeed all of the interconnected and overlapping food chains contain many organisms that take place within various niches because their resources are available for their habitat (Mader, 1996). Various types of organisms within the food web are grouped into categories called trophic levels. In this food web case study, we will use the food web as a directed graph to model the relationship between predators and prey in an ecological community and the use of graph to visually explain the important parameters that consider a competition for ecological surroundings for organisms. As directed in a simple food web of an ecological community, the graph displays an apex for each organism in a trophic level and a direct border from the apex visually explaining individual A to the apex illustrating individual B, and however, the path continues if A preys on B (Roberts, 1976). Within this particular graph, the toad, milk snake, salamander, raccoon, grasshopper, fox, and the robin were chosen for a group of seven species, and the results show competition among one another. Again, if there is a common prey to catch, the species will compete for the catch, two species will compete for the catch. The graph displays the vertex of the raccoon...
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...which has been vastly reduced over the century and one of the contributing factors is poaching. When a significant number of a species is wiped out by poaching, the result is that the gene pool is reduced dramatically, and the species must repopulate itself with the alleles available, the genetic diversity is reduced, similarly to the genetic bottleneck effect although the reason for mass species reduction is not due to natural causes. So although poaching can lead to reduced diversity in one species, it can potentially increase in another. The reason being over hunting can lead to a trophic cascade, where the number of a top predator is increased/decreased – decreased in this case - from the food chain, as a result the abundance of the other trophic levels are effected e.g. if lions in the savannah are reduced, the antelope in the next trophic level is increased, and the grass in the next trophic level is reduced. In conclusion poaching can have a minor increase in the genetic diversity of some species; however the species that is directly affected has its genetic diversity vastly reduced....
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...Week 3 ILab Joy Major Exercise 1: A biomass pyramid is a diagram that shows the flow of energy through each trophic level of a food chain by quantifying the amount of biomass present at each trophic level. As a general rule, 90% of the energy is lost as you move through each trophic level. The levels move as follows: primary producers to primary consumers/herbivores to secondary consumers (predators) to tertiary consumers (top of the food chain). For example, in an eastern deciduous forest, if the primary producers (i.e., deciduous trees, shrubs, and grasses) produce 10,000 kilocuries per square meter a year then the kilocalories available at the primary consumer level (i.e., bugs, deer, rabbits, small birds) will be 1,000 kilocalories; followed by 100 at the secondary consumer level (i.e., foxes, owls, skunks, large birds) and 10 at the tertiary consumer level (i.e., bears). An example of this flow of energy can be found below. Exercise 2: Mount St. Helens has revealed some important factors that influence how an ecosystem can recover from such a cataclysmic eruption. One mudflow had cut through a forest, so it was surrounded by existing vegetation and recovered relatively quickly. The seasonal timing was a key factor because spring was late in coming to Mount St. Helens that year, and so there were still drifts of snow covering the understory of many sections of the forest, protecting the plant and animal species buried beneath them. The snowmelt also protected...
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...including a series of arrows, each pointing from one species to another, representing the flow of food energy from one feeding group of organisms to another. Food web offers an important tool for investigating the ecological interactions that define energy flows and predator-prey relationship (Cain et al. 2008). The fundamental purpose of food webs is to describe feeding relationship among species in a community. Food webs can be constructed to describe the species interactions. All species in the food webs can be distinguished into basal species (autotrophs, such as plants), intermediate species (herbivores and intermediate level carnivores, such as grasshopper and scorpion) or top predators (high level carnivores such as fox) 1 This chapter addresses how knowledge of the body sizes of prey and predators can augment understanding of feeding ( “ trophic ” ) interactions among individuals, and the structure and dynamics of complex food webs. 2 Foraging characteristics of individuals, such as visual acuity and movement speed, can be combined with...
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...is hunted by a hawk. A food chain clearly shows this pathway of food consumption. You could probably think of another food chain for a forest ecosystem. In fact, many different food chains exist in ecosystems. Although there are many different kinds of food chains, each food chain follows the same general pattern. A link in a food chain is called a trophic, or feeding level. The trophic levels are numbered as the first, second, third, and fourth levels, starting with the producers. Each of the trophic levels is occupied by a certain kind of organism. Producers are always in the first trophic level since they do not feed on another organism. Consumers occupy the rest of the trophic levels. The second trophic level is the first consumer in the food chain and is called a primary consumer. Primary consumers eat plants and are therefore herbivores or omnivores. The next consumer in the food chain is the secondary consumer. The secondary consumer is in the third trophic level. Since the secondary consumer feeds on another animal, it is a carnivore or an omnivore. Similarly, the tertiary consumer occupies the fourth trophic level, and is a carnivore. The last link in a food chain...
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...* In the Lake Michigan food web, is it possible to identify the most important producer? Why or why not? It is not possible to identify the most important producer. There are multiple consumers which are consumed by several different primary consumers. The image was blurry so it was difficult to determine what everything was in the food web. * What would happen if there was a change in the population size for any one of the producers (either an increase or a decrease)? How could these changes impact other producers and organisms on other trophic levels? If there were an increase in population in any one of the producers, they would begin to dominate the other producers and therefore would increase the number of consumers which feed on the producer. If there were a decrease in one of the producers then there may be a decrease in consumers that are reliant on the producer for food or the consumer could choose a different producer. If the consumer chose a different producer for food, the result would be a depletion of this producer. It could end up like a snowball effect by one affecting the other. * Provide at least two types of impacts that humans could have on this food web. Burning of coal can cause air pollution which can cause acid rain and change the ecosystem of the lake. http://www.ucsusa.org/clean_energy/coalvswind/c02b.html Dumping of toxins into the lake which could disrupt producers and have an effect on producers. * Read the description of the sea...
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...from trophic level to trophic level (fig. 49.1). Food chains rarely are unbranched since several different primary consumers may feed on the same plant species and a primary consumer may eat several species of plants. The feeding relationships are usually woven into elaborate food webs within an ecosystem. Ecological Pyramids 1. A pyramid of productivity has trophic levels stacked in blocks proportional in size to the energy acquired from the level below. Food chains are usually bottom heavy since only 10% of energy is transferred. 2. A biomass pyramid has each tier symbolising the total dry weight of all organisms in an ecosystem's levels at any given time. Biomass represents chemical energy stored in the organic matter of a trophic level. Most narrow sharply from producers at the base to top-level carnivores at the top. Some aquatic systems are inverted since producers can have high turnover rates. They grow rapidly but are consumed rapidly, leaving little standing biomass. Biomass of top-level carnivores is usually small compared to the total biomass of producers and lower-level consumers. Food chains are limited to 3-5 links due to the multiplicative loss of energy. This also limits the biomass of top-level carnivores that can be supported. Only about 1/1000 of the chemical energy fixed by photosynthesis flows through a food web to a tertiary consumer, only 3 -5 trophic levels can be supported since biomass at the apex is insufficient to support another level. The...
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...Mohammed Konneh BIO 171-B Ralph Spagnolo March 29, 2016 Midterm Essays Anti-environmentalists argue that “people have always polluted the earth” not knowing the reason we should care about the pollutions is in that quote itself. Humans have been polluting this planet since the dawn of mankind and at some point in time we have to understand that these pollutions would start to have an impact on the way we’re used to living. At first people ignorantly polluted the earth and depleted resources that are to be shared with the other species that are in our ecosystem but when rivers started to dry and animals began to mysteriously migrate, people started to take notice and the study of organisms and their interaction with their non-living surroundings. It is true that people have always polluted the earth but the majority won’t understand the fuss over ecology and the effects pollution have on ecology because modernization blinds us from the species in our ecosystem and what they’re going through as we progress with modernization. Like the ripples that appears when rock hits the water, our ecosystem too have ripple effects when an area is polluted. Take for example when the toxic emissions that comes out of cars, the birds in the sky aren’t used to the toxins in the emissions and when some of them breathe it in they die limiting the population of the birds in the ecosystem. Since there are less birds in the ecosystem, snakes and other predators that depend on the bird for...
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...Figure 3 shows a food web made up of many levels. The first, the producer, absorbs the most energy from the sun (around 10% of sun’s total energy output- this is the highest amount of energy received in the whole chain). Without the producers energy would not be obtained and the whole web would terminate. The second trophic level consists of primary consumers. These can only be herbivores, such as rabbits and worms, they will only eat the plants. Trophic level 3 of the food web comprises of secondary consumers, which stereotypically consume other animals. An example of this is the owls, which consume small birds. In figure 3 the final trophic level is the tertiary consumers, which consists of the top predators that often prey upon most of the other animals in the food chain, figure 3 shows how an owl will prey on both beetles and larger animals such as mice and voles. At each trophic level, 10% of the energy consumed by the predecessor is passed on, meaning that animal must consume lots of food in order to gain the correct amounts of energy for basic functions such as respiration, digestion and excretion. Dead organic matter is highest near the bottom of the food web as the nutrients released from the decomposing plants and animals releases lots of nutrients which helps the plant to grow. This is resulting from decomposers such as bacteria and algae. Studland bay in Dorset contains a classic psammosere (dynamic vegetation succession, which characteristically increases inland)...
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...1.4.6 Energy Flow Worksheet What is an ecosystem? An ecosystem is a _________________________________________ with ___________________ and their __________________________ within _____________________, e.g. woodland, etc. Energy Flow Ecosystems are unable to function unless there is a constant ________________________________ _____________________. Where does this energy come from? __________________ The Sun The sun is the _________________________________________________ for our planet. Energy Flow is the _________________________________________________ from one organism to the next in an ecosystem due to ________________, e.g. along a food chain Feeding allows _____________________________________________________ in an ecosystem. Energy flow in the ecosystem Food Chain Is a flow diagram that begins with a _______________ and shows how _____________________ is passed through a series of ______________________________________. Each organism feeds on the one before it. A food chain ends when there is _____________________________________________________. An example of a food chain: __________ ( ____________ ( ______ A Grazing food chain is one where the __________________________________ e.g. ________________ ( grasshoppers ( frogs ( hawks ...
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...PART III GRAPH THEORY 224 13 Food Webs Author: College. Robert A. McGuigan, Department of Mathematics, Westfield State Prerequisites: The prerequisites for this chapter are basic concepts of graph theory. See Sections 9.1 and 9.2 of Discrete Mathematics and Its Applications. Introduction A food web is a directed graph modeling the predator-prey relationship in an ecological community. We will use this directed graph to study the question of the minimum number of parameters needed to describe ecological competition. For this purpose we will consider how graphs can be represented as intersection graphs of families of sets. We will also investigate the axiomatic description of measures of status in food webs. Competition In an ecological system, the various species of plants and animals occupy niches defined by the availability of resources. The resources might be defined in terms of factors such as temperature, moisture, degree of acidity, amounts of nutrients, 225 226 Applications of Discrete Mathematics and so on. These factors are subject to constraints such as temperature lying in a certain range, pH lying within certain limits, etc. The combination of all these constraints for a species then defines a region in n-dimensional Euclidean space, where n is the number of factors. We can call this region the ecological niche of the species in question. For example, suppose we restrict ourselves to three factors, such as temperature...
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