The Birth of a New Lesson
By Rink Somerday
The Asombro Institute for Science Education staff is always looking for regionally relevant, cutting edge science to incorporate into our hands-on, classroom lessons. It often starts with a science topic or science education standard that classroom teachers seek support in meeting. The wheels begin to turn as we ask ourselves, how can we teach this best? How can we make this relevant to our students’ lives? How can we make this fun? Our latest classroom program, “Natural Selection of Blanched Lizards at White Sands,” began this way.
We started with the topic of natural selection and the Next Generation Science Standard MS-LS4-4: “Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals’ probability of surviving and reproducing in a specific environment.” Wanting to present students with an intriguing, local example of natural selection Executive Director Stephanie Bestelmeyer began to read recent research papers on the white to light grey colored (also known as “blanched”) lizards at White Sands National Monument.
In the past seven years, Dr. Erica Bree Rosenblum from the University of California, Berkeley and her colleagues have learned a tremendous amount about the development of blanched lizards over the past 6,000 years at White Sands. They discovered that a single genetic mutation on the Mc1r gene in three species results in the lighter colored lizards. These blanched lizards camouflage better on the white, gypsum sands at White Sands than the lizards with darker pigmentation that are found in the surrounding desert. In only 6,000 years, these lizards in our beloved White Sands are an exemplary study of evolution in action.
After weeks of studying, the Asombro staff began the process of converting this research into multiple hands-on activities that get students engaged from the moment they sit in their seats. First, students tap into their previous knowledge of camouflage by locating camouflaged animals in photos on their tables.
Then students rotate through “mini-stations” to understand the three stages in the development and spread of the blanched coloration trait over time:
1. Changes to genes (mutations) may affect proteins, which affect an individual’s traits.
2. Genetic variation of traits increases some individuals’ probability of surviving and reproducing. The beneficial traits may be passed on to offspring.
3. Natural selection may lead to increases of specific traits in populations over time.
At mini-stations, students use models and hands on activities to better understand each concept. They use a hands-on model of a gene to assemble a model protein and determine if their lizard is blanched or non-blanched. They imitate a roadrunner looking for lizards to eat to see which lizard trait (blanched or non-blanched) has a greater chance of survival and reproduction. They simulate fieldwork by monitoring lizard populations over time as the environment at White Sands changes. At the end of the lesson, students apply the three stages to one of the other camouflaged local animals they saw in the introductory activity.
Asombro staff are now finishing the creation of the lesson and accompanying worksheet. Our next step is to pilot test the lesson in a local school, looking for student comprehension of the directions, timing, and understanding of the concepts. Once all of this has been completed, we will deliver it to every 7th grade student in the district in spring 2018.