Cause and Effect: Mechanism and Prediction |
| Events have causes, sometimes simple, sometimes multifaceted. Deciphering causal relationships, and the mechanisms by which they are mediated, is a major activity of science and engineering. |
|
Malaria & Sickle Cell Anemia
In this modeling exercise, students explore historical factors resulting in the differential presence of sickle cell anemia across the globe to learn about the cross-cutting concept “Cause and Effect”.
This modeling exercise uses sickle cell anemia as a phenomenon to get students to think about how deleterious genetic traits can continue to exist in populations via a heterozygous advantage. By framing selection (effect) as the result of a pathogen presence (cause, a plasmodium causing malaria in the population). Student modeling of this can be approached in the following way: 1) Have students draw a population of humans with some percentage with sickle cell anemia. 2) Then draw how this percentage might change over generations (assuming all those with sickle cell anemia die before reproducing). This would show the percentage decreasing. 3) Then have students change the environment of this population to one where malaria is present and ask students to model this again. In this case those heterozygous will have an advantage allowing maintenance of the sickle cell anemia gene. |
|
Suggested Modeling Elements: Cells: General, Cells: Blood; Biomolecules: DNA; Biomolecules: RNA Suggested Sensemaking Components: Zoom in/out; Movement/Motion; Flow of Matter |
