One of the criteria students must consider is how the internal systems of humans, such as circulatory or digestive systems, might have to be changed to better allow for survival in the extreme ecosystems that students are considering. This lesson provides students with a real world example to jump start their thinking in this direction.
As students enter the room they respond to the following prompt:
Consider the extreme ecosystem you have chosen for your project, how might the following internal systems be impaired (less able to function) in that environment?
Students work in their groups to brainstorm and complete what they can using the Challenges To Internal Systems handout to organize their thinking. Students may not have a lot of ideas at this point, however they will revisit this chart again during the wrap-up portion of this lesson.
As I have stated in prior lessons, HHMI's Biointeractive is a fantastic resource. They do a great job at creating interesting and relevant videos that are easy to understand while providing students with real world examples described by scientists working in that field. The following video not only talks about the specific adaptations of the icefish, but also explains "the birth and death" of genes.
The video is a bit over 13 minutes long. Students can jot ideas down but I don't require they do as I like them to be able to focus on the video (and there is no way that I can stop myself from pausing the video to elaborate and discuss some of the points that are relevant to the redesigning humanity project!).
The following video provides some ideas on how to incorporate the cross-cutting concepts within this lesson or throughout the unit in general. I have found that referring to these concepts as "how scientists think" helps both students and teachers better connect with ideas as they see the natural infusion within the classroom.
Now that the students have seen an example of real world adaptations to extreme environments, students revisit the chart given during the warm-up. Students again work in groups to discuss/develop ideas for how each of the listed internal systems might be impaired by the new ecosystem.
Students are encouraged to include ideas for changes and/or questions they need to look into in their chart as shown in the Student Example: Challenge Chart.
Once students have completed the chart, they will select the two systems on which they will focus to meet the requirements of the project as listed in the End of Humanity Student Checklist from the lesson Introduction of PBL: Is It the End of Humanity.