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Students often find it challenging to learn about complex and abstract biological processes. Using the engineering design process, which involves designing, building, and testing prototypes, can help students visualize the processes and anchor ideas from lab activities. We describe an engineering-design-integrated biology unit designed for high school students in which they learn about the properties of slime molds, the difference between eukaryotes and prokaryotes, and the iterative nature of the engineering design process. Using the engineering design process, students were successful in quarantining the slime mold from the non-inoculated oats. A t-test revealed statistically significant differences in students' understanding of slime mold characteristics, the difference between eukaryotes and prokaryotes, and the engineering design process before and after the unit. Overall, students demonstrated sound understanding of the biology core ideas and engineering design skills inherent in this unit.
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Substrate composition directs slime molds behavior
Abstract Cells, including unicellulars, are highly sensitive to external constraints from their environment. Amoeboid cells change their cell shape during locomotion and in response to external stimuli. Physarum polycephalum is a large multinucleated amoeboid cell that extends and develops pseudopods. In this paper, changes in cell behavior and shape were measured during the exploration of homogenous and non-homogenous environments that presented neutral, and nutritive and/or adverse substances. In the first place, we developed a fully automated image analysis method to measure quantitatively changes in both migration and shape. Then we measured various metrics that describe the area covered, the exploration dynamics, the migration rate and the slime mold shape. Our results show that: (1) Not only the nature, but also the spatial distribution of chemical substances affect the exploration behavior of slime molds; (2) Nutritive and adverse substances both slow down the exploration and prevent the formation of pseudopods; and (3) Slime mold placed in an adverse environment preferentially occupies previously explored areas rather than unexplored areas using mucus secretion as a buffer. Our results also show that slime molds migrate at a rate governed by the substrate up until they get within a critical distance to chemical substances.
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- Award ID(s):
- 1552368
- PAR ID:
- 10153846
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 9
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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