Association for Biology Laboratory Education

Proportions, not numbers – a computer simulation that facilitates students’ understanding of natural selection
 

Malin J Hansen

Advances in Biology Laboratory Education, 2022, Volume 42

https://doi.org/10.37590/able.v42.art30

Supplemental Materials: https://doi.org/10.37590/able.v42.sup30

Abstract

Students hold several misconceptions related to natural selection and evolution. They therefore often find it difficult to explain mechanisms and predict when evolution will occur. For example, if a population of white rabbits is preyed upon by wolves, students may state that evolution has occurred because the number of rabbits decreased (even though the proportion of white rabbits stayed the same). Alternatively, students may state that evolution will occur because rabbits are forced to change fur color. This activity gives students an opportunity to confront their misconceptions. Students first predict the outcome of different scenarios, e.g. in the presence or absence of variation within a population and in the presence or absence of selection pressures. Thereafter, they run a simulation and graph changes in the number as well as the proportion of individuals with different traits over time to test their hypotheses. The activity can be expanded upon in several ways and is suitable for introductory biology for both majors and non-majors. The exercise can be used in lab, in lecture, or be assigned as an assignment.

Keywords:  simulation, exponential growth, natural selection, Evolution, population growth, misconceptions, selection pressure

Virtual ABLE (ViABLE) (2021)