Lesson 12 · Check-in 2

How Healing Happened Chart can be used as a formative assessment opportunity. At this point in the unit, students have figured out a lot about how the body heals from an injury all the way down to the cellular level. Now they are being asked to think about whether these processes could be the same for a lizard or sea star who is injured and loses an appendage. This handout can be used to gauge where students are at in their thinking about how cells make new cells to repair an injury and whether students think that happens in other organisms. Look for students to begin applying the conceptual model they have developed in this unit to the last question on the handout by explaining they would want to know if the lizard and sea star also have cells and have similar systems we have that can bring nutrients to the cells so that the injury can heal.

In addition, when students see that the appendage heals by regrowing from the place of injury, students will begin to think about how growing and healing can be similar. In the next lesson, students will analyze data about growth plates in younger people and what happens at these locations over the course of someone’s life. You may see students begin to argue that these processes are the same.

• Use of this handout as a formative assessment is for informing you of where your students are in their sense making prior to the next lesson and such shouldn’t be graded.
• Give students about 10 minutes to complete Lizard and Sea Star Injury Cases. Then bring the class together and discuss their ideas.

Suggested prompt

Sample student response

What were some things you and your partner noticed about the two cases?

• Both the lizard and the sea star can lose part of its body and then have it grow back as it heals.
• Yeah, the injury to the lizard was that it lost its tail, but then the healing was that it grew a new tail! Same with the sea star - it lost an arm and grew a new arm as it healed.
• It didn’t just heal on the end where the tail or the arm came off like our skin would if it was scraped. It seemed to heal at the end and grow that part back.

So wait, both the lizard and sea star healed right?

Yeah.

But you are saying that it also grew somehow?

Yeah both of them grew back a body part that they had lost when injured.

So then do you think healing and growing might be a similar process?

Maybe… since in order to grow we would need to make more cells.