Understanding competition between organisms is critical to ecological literacy
and to understanding the invasion of exotic species into new ecosystems. Despite the
importance of competition as a foundational ecological concept little is known about
middle school students’ understandings of competition. This study sought to determine
students’ beliefs about inter- and intraspecific competition in general and how
competition explains why some exotic species become in invasive. A second goal of the
study was to establish the extent a problem-based unit could support normative
understandings of competition through engaging students in science and engineering
practices. 143 sixth grade students’ responses on one multiple choice and two open-ended
questions were analyzed pre- and post unit implementation. Students were taught by one
of three different teachers. Patterns in student responses were captured by developing
codes through thematic qualitative data analysis (Braun & Clarke, 2006). Frequencies in
matched-pairs codes were compared pre to post using the McNemar test to discern
changes in student thinking. This work is funded by the Herbert H. and Grace A. Dow
Foundation.
Results/Conclusions
Pre-test responses demonstrated that between 18-33% of students (depending
upon class) believed that plants either do not compete for light or do not compete for any
resources. There was significant positive conceptual change from pre-to posttest in all
three classes regarding plant competition for resources. Students had little knowledge
about invasive species on the pre-test as indicated by the high percent of students who did
not answer the related question (25%-40%). Significantly more students indicated
invasives disrupted food chains/webs or took native’s resources on the post- test
compared with the pre-test (p=.039). On the post-test, students’ understandings were
strongly influenced by the teacher. For example, while 22.2% of students in one class
specifically used the phrase “Take over” in their post-test responses to describe invasives,
only 4.3% and 3.9% of students did in the other two classes. These findings demonstrate
that problem-based learning instruction that contextualizes competition within science
and engineering practices can promote middle school students’ understanding about
competition. However, teacher beliefs and the words they use to describe invasive species
are critical and should be investigated further.