The Four Big Ideas…In an Apple

Tomorrow will be the fourth day of school. It’s been a good week, and I’m loving teaching AP Biology again.

I put together a two day lesson sequence to teach my students about the Four Big Ideas, which I’m using as the themes for my course. My lesson goal: in a written homework assignment, students would be able to describe how the Four Big Ideas apply to an organism of their choice. Here’s what I did.

DAY 1 

    1. I bought 8 apples for each class. The apples were of 8 different varieties (Granny smith, Red Delicious, Jazz, etc.).
    2. I divided my class into lab groups (4/group)
    3. I provided each group with a cutting board and a knife, and gave them the following instructions:
      1. Look over your apple’s exterior. What parts do you notice?
      2. Cut a small slice.
      3. Notice the skin…the flesh underneath.
      4. Carefully slice the apple in half (SAFETY!!!)
      5. Notice the changes in the apple’s structure as you move from the outer skin to the core.
      6. Take out an apple seed. Dissect it with your fingers. Notice the inner parts
      7. Quarter the apple so everyone in the group can eat it.
    4. After five minutes, I called the class together and gave them this discussion prompt:
      1. Biology is the science of life. Our course approaches biology through four themes
        1. Evolution
        2. Systems and System Interactions
        3. Information flow
        4. Matter and Energy flow



Note: An AP Bio class at Berkeley High School is a lot less diverse than our school as a whole (to our shame, we have the biggest achievement gap in the United States–we’re working on it, but we have a long way to go). But we still have a fair measure of diversity, and I try to structure discussions so that every voice can be heard. Even something as a ROUND ROBIN structure can help: The instructions are: Take a moment to think. Go around the circle. Everyone has a turn to contribute for a maximum of one minute. As students talk I move around, briefly listening in to provide a least some accountability. 

  1. After about 5 minutes of discussion, I had students write their responses.
  2. I gave a short powerpoint presentation that walked them through the themes. Note that I’d done a tiny introduction to the four themes on the 1st day when I was introducing the course.
  3. I had them do a short reading about the four big ideas (just the section entitled “Course Themes”).
  4. They had another 5 minutes to think about how they would apply these themes to an apple (and an apple tree).
  5. They had 10 minutes to capture their thoughts in writing (again, How do you see these four big ideas in an apple?
  6. As a homework discussion, I had them read, underline, and annotate (using a “They say” / “I say” structure) my own version of the same assignment (telling them that this goes way beyond what I’d expect them to do at this point).


  1. I checked in on their reading and annotation by responding to questions.
  2. I then gave them this assignment (again, for homework): Using last night’s reading and your work applying the four Big Ideas to an apple as a model, apply the four Big Ideas to an organism of their choice. I’m planning on giving them the Labor Day weekend to work on it, and I’ll probably use some peer evaluation method to look at it (because I know I’m not going to have the bandwidth to read 70 of these next week!)

Hope that’s useful, and I’d love to know what you think!