Competition – Why Are “Weeds” So Successful?

 

Debby Luquette

Tested Studies in Laboratory Teaching, 2011, Volume 32

Abstract

This exercise investigates plant competition in which garden plants substitute for two common weeds. Spinach and black mustard stand in for lamb’s-quarters (Chenopodium album, L.) and garlic mustard (Alliaria officinalis, M. Bieb.) respectively. Both wild species germinate and grow in the same conditions in late summer, although lamb’s-quarters flowers in the fall and garlic mustard, a winter annual, blooms in spring. In the early weeks, students examine the growth characteristics to determine if there is any difference in allocation of resources to shoot or root growth between black mustard and spinach when each are grown separately in pots. They also investigate if resource allocation changes when the species are grown together in competition in pots. This exercise is designed for non-majors and first-semester environmental science students, who have had little experience in lab or in writing a lab report. This exercise prepares students to analyze a complex lab problem, write a formal lab report, interpret data, and make graphs for a later exercise during the semester. The discussion questions also are meant to serve as a model to help guide students through the type of questions they should ask themselves for the later exercise.

Keywords:  ecology, competition, resource allocation

Dalhousie University (2010)