This activity explores images of planarians regenerating missing body parts, which serve as phenomena for learning about cell division and differentiation.

Planarians are simple multicellular animals known as flatworms. They can regenerate parts of their bodies using adult stem cells called neoblasts. When part of a planarian is cut off, its neoblasts multiply to make more stem cells. Some of these stem cells then differentiate into the cells needed to regrow the missing body parts. These images show how planarians cut in different ways regenerate over time. One of the planarians has been treated with RNA interference (RNAi) to shut off a gene involved in establishing body polarity.

The “Educator Materials” document includes background information and implementation suggestions for using the images as phenomena. The “Student Handout” includes the images and background information.