Socrates Fellows Our Projects Biology Roundworms (Nematodes) in the Classroom
Biodiversity, genetics and ecology
Gloriana Gallegos Trujillo and Jessica McSwain, a biology teacher at Hilltop High School in Chula Vista will introduce C. elegans in as many of the biology curriculum units as possible. They have two main activities planned for the students. The first is to isolate C. elegans and other nematodes from soil samples at the school and discuss their findings in the context of biodiversity and ecology. The second activity will be to use C. elegans as a model for the genetics unit, using genetic crosses to illustrate Mendelian inheritance, sex chromosome linkage, dominance and recessivity. This discussion of roundworms will allow them to illustrate that these tiny organisms are the cause of serious plant and human diseases as well as model organisms for biological research.
Grade Level: High School, 9-12
Duration: Day 1: 50 minutes
Day 2: 50 minutes
Big Idea: Terrestrial ecosystems rely on organisms such as decomposers to provide nutrients. The soil isolation activity gives students a chance to learn about microscopic organisms living in the soil that contribute to the cycling of nutrients.
Abstract: The soil ecosystem is a good model for discussing trophic levels, energy flow, and element cycling. Isolating organisms living in the soil is a great way to start discussing these topics while giving students a real-time application and understanding of ecological concepts. Asking students to prepare a soil sample that has fruit rotting in or on top of the soil must be done at least one week in advance. Samples taken from compost heaps are useful. Samples are plated onto plates that contain non-virulent E. coli and are inspected immediately, then again as early as the following day. The activity provides a firsthand look at microscopic fungal, bacterial and organism growth over the course of a few days in a controlled environment. Students will make predictions about what they believe will grow in the soil, observe the life that grows in their sample, discuss results with classmates, and formulate questions about their findings. Conclusion questions assess whether students learned about the organisms that live in soil.
Learning Objectives:
1. Students will be able to practice scientific method by making hypotheses, observations, collecting data and formulating conclusions.
2. Students will be able to demonstrate their knowledge about trophic levels and biotic relationships in the soil.
