Food Web Case Study
Brenda Phouthavong
MTH/221
September 8, 2014
Gary Page

Food Web Case Study
In a single 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 and fox since the robin is a common prey. The vertex of the milk snake and raccoon shows that both species compete for their common prey, the grasshopper. The vertex of salamander and the robin do not compete with one another since they do not share the same prey. The result of a simple food web clearly displays a competition relation. In other words, different species will compete with one another to catch a common prey to eat than those who do not share a common prey will not compete against each other.
Various species of all sorts inhabit niches; it is the practical relationship of an organism to its substantial and biotic domain. The resources that are referred to in terms of factors include the weather like the temperature, moisture, degree of acidity, amounts of nutrients, and then some. However, these factors are subject to resistance like the temperature in a certain spot and pH lying within certain limits (Roberts, 1976). We can consider that these subjects to resistance for a species defines a region on a graph in n-dimensional Euclidean space whereas n is the number of factors, the following region is called the ecological niche of the species in question according to Roberts in Discrete Mathematical Models with Applications to Social. In simple terms, two different species will not have the same ecological niches; however, they will compete if their ecological niches have open paths through their intersection. Consequently, base on the ecology principle, such as the principle of competitive exclusion, two different species whose niches are too similar, or overlap too much cannot happen in the same place or at the same time (Mader, 1996). In another thought, we should consider that niches are multidimensional because they include a wide variety of aspects of the environment. Defining a niche may be a bit complex, so we break it down in three sets of parameters: 1. Range of physical factors for survival and reproduction, temperature, humidity, phi soil, and sunlight 2. Biological factors: predators, prey, parasites, and competitors 3. Behavior: seasonality, diurnal patterns, movement, and social organization, therefore, the list of sets provided are the study of parameters to describe ecological competition (Mader, 1996). The concept of ecological is separated from the concept of niche because the definition of ecological defines the place where an organism lives, such as its habitat, as well as all the aspects defined above.
In a food web, organisms are grouped into categories called trophic levels. Trophic levels were a way to measure the estimation of an organism within the food web. It is a helpful method to understand the complexity and diversity of the food web because most of the organisms on the tropic status have many complications of own purpose (Roberts, 1976). In other words, we believe that more complex ecosystems are more stable likely of all the resources and advantages of them. Within the food web, trophic status is easy to define if and only if it is a directed path, like a food chain, simple enough to breakdown the order of the organisms in the latter (Roberts, 1976). In a simple web, the prey that are eaten are placed at the bottom, and the top are the predators that hunt them, and the middle web are prey to common predators as well and are predators to their prey at the bottom.
The food web is the food chain to many in a single ecosystem. Evidently, if not all than most that are living in an ecosystem is part of the food chain, and then some. A food web is a direct path that shows layers of trophic levels by their complexity. The species that inhabit in niches are there for their resources that make it available for their habitat and its ecological understanding to sustain it. The explanation of a directed graph that models relationship between predator and prey indicates a visual effect of measuring the tropic status of those particular species. The parameters provided in the case study are the minimum important factors that contribute understanding and explanation of ecological competition in the very beginning.

Reference
F. Roberts, Discrete Mathematical Models with Applications to Social, Biological, and Environmental Problems , Prentice Hall, Upper Saddle River, N.J., 1976.
Mader, Sylvia S.1996. Biology - 5th Ed. WCB and Cox, G.W. 1997. Conservation Biology - 2nd ed. WCB