Economics and Biology: An Analogy for the Presentation of the Niche Concept

Abstract

In a first-level college biology course the niche concept is fundamental in introducing ecology. Few students at this level, particularly those in a nonmajor course, have had the opportunity to gain an appreciation for the incredible number of interactions possible among members of a biological community. This presents a difficult task for the lecturer in illustrating the richness and complexity of the niche concept. In the general biology course for nonmajors that I teach at Baylor University I use an analogy that has been successful in communicating the multidimensions of niche strategies. The analogy is developed from a study conducted by Kangas and Risser (1979) on species packing in fast food guilds. I introduced the analogy by displaying a transparency that lists all of the restaurants and eating establishments in Waco, Texas. The use of this transparency and the relating of basic economic principles to ecological principles can initiate a number of discussions and introduce a number of ecological concepts. My specific objectives are to define niche and niche parameters, define competition and introduce the concepts of resource partitioning, the competitive exclusion principle and the compression hypothesis of ecology. After presenting the students with the general definition of niche as the role or profession of the organism within the community, I ask them to define niche for the establishments listed. The students generally answer that the niche can be defined as providing prepared food for the people of Waco. When asked for a more specific definition the students begin to point out the differences among the restaurants and use these to define the niche for a particular restaurant. Differences commonly listed include the kinds of food served, the time required to obtain a meal, prices, the hours open, the location, ambiance, type of service (counter service versus waiter/waitress), and the presence or amount of inside seating. These factors are used to indicate the dimensions of niches and how niches can be measured. General comparisons of niche width also can be made by comparing establishments with narrow specialized niches (i.e. Super Spud or the Great Hot Dog Experience which serves only a single type of food) with those having broad generalized niches (i.e. Denny's which is not known for any particular type of food but rather a wide variety). Characteristics of different niches are then used to introduce and emphasize the role of competition in niche formations and community structure. To do this, the number must be identified as the basic resource that is in limited supply. I use a question/answer format to help the students recognize these points. Questions such as What must a restaurant do in order to stay in business? or Why are some establisments more successful than others? help guide them in this direction. By the end of this discussion, the students, usually with only a little help from me in the way of questions, have established that the restaurants are dependent upon the money procured by attracting customers and their ability to attract customers is dependent upon the services they offer (niche strategies). Success is also determined, in part, by how many other establishments offer the same services (competition). The next step is to introduce the concept of resource partitioning and to compare competitive intensities among the different restaurants. For this portion of the discussion I usually focus on fast food restaurants (FFRs), which are well known by most college age students. By limiting the discussion to FFRs, it is easier to establish the portion of overlap in their niches (i.e. all specialize in preparing and presenting the food in a short amount of time, similar atmosphere and types of service, comparable prices) and also point out that each clearly attempts to offer some unique product (i.e. Mexican, fish, versus hamburgers) or service (i.e. morning meal, open 24 hours, We will fix it your way). When asked to explain the characteristic differences among the FFRs, students quickly tell me that the differences help in attracting a different segment of the customers (resources). In essence, the resources are being divided or portioned out among the different establishments (resource partitioning). At this point, I introduce the ecological concepts of the competitive exclusion principle (two species cannot coexist indefinitely when they have the same niche) and the compression hypothesis (as the number of competitors increases, niche overlap and niche width decrease), drawing examples from the previous discussion along with examples from biological studies. This analogy provides a way of introducing the ecological complexity of biological systems in a framework in which the students are comfortable and one in which they can contribute to their understanding. It also illustrates the common ground between two seemingly unrelated disciplines, economics and biology. The value of this point must not be overlooked when teaching a university required course for nonbiology majors.