Teaching Students About Biodiversity by Studying the Correlation Between Plants & Arthropods

Biodiversity is an ecological buzz-word that has garnered a great deal of attention for the past several decades. The main focus has been on human effects on biodiversity. Humans mainly affect biodiversity directly through development, which decreases wildlife habitat (Dodd, 1987; Greene, 1997), or indirectly through habitat fragmentation, introduction of exotic species, or alteration of natural cycles (e.g., suppression of natural fires; McClain 8z Anderson, 1990; Owens ST Cole, 2003). Much attention has been given to human impacts on biodiversity and many lessons about this topic have been developed for the classroom (Kishbaugh, 2002; Almeida et al., 2006). While biodiversity curricula for the classroom have been inventive and noteworthy, students first need an introduction to biodiversity, including an introduction to the concept, common ecological terms often associated with biodiversity, factors that may affect biodiversity of a particular taxon, and ways of measuring biodiversity. Teachers face the challenge of introducing this concept in an authentic way which students can apply to their surroundings. This can be especially challenging in urban environments which are human-centered habitats and often low in green spaces and diversity. On Earth there is a huge diversity of arthropods, many of which are highly adaptive and able to exploit virtually every terrestrial habitat. Because of their prevalence even in urban environments, they make an excellent model system for any life science class. Since plants also exploit virtually every terrestrial habitat, studying the relationship between plants and insects is accessible to all classrooms. The relationship between plants and arthropods is worthy of investigation because the diversity of arthropods, especially insects, exploded when angiosperms evolved. Insects use plants for food, but plants also increase habitat space and thus, trophic complexity. Studying the relationship between plants and arthropods will help students understand that organisms among different taxa are interconnected. Two components of biodiversity are richness (i.e., number of species) and abundance (i.e., number of individuals of each species or taxa). The objective of this project is for students to investigate how plant richness affects insect biodiversity (i.e., richness and abundance across taxa). The plant community directly affects arthropod abundance and richness, so biodiversity of arthropods should be positively correlated to plant richness (Siemann et al., 1998). In urban environments, the plant community is fragmented and often represented by a limited number of species. We developed this project in an urban environment with middle school students to demonstrate how arthropod biodiversity can easily be increased by simple habitat modifications to their yards. Working outside the classroom in students’ backyards is the sort of authentic “hook” we need as teachers to snare our students’ attention and engage in real learning. Thus, we developed a simple experimental protocol for studying biodiversity that will allow you and your students to determine the diversity of arthropods in various urban habitats. The project is easy to perform, took only two 43-minute class periods, one for an introduction and another to sort samples and enter data into spreadsheets, and, as you will see in the discussion that follows, it can be modified to apply to multiple grade levels. We also found it to be an effective learning experience for the students, and their level of motivation and enthusiasm was very high. Materials & Methods Students were given a pre-activity quiz to assess their knowledge of ecological terms associated with this lesson (Table 1). Following this, we discussed the terms on the quiz, demonstrated how to measure plant richness and collect arthropods, and gave students the necessary packet of materials. The packet of materials included one plastic yellow bowl (Solo Cup Company, Urbana, IL), a one-meter long piece of string, an instruction and plant data sheet (Table 2), and a plastic container with a lid (some students used peanut butter jars or other containers from home).