What can I learn from worms? June 2012
Lesson 2: How do planarians react to their environment?
Planarian Observations
1A. What happens when you give planarians food?
Place some food for the planarian in a petri dish and observe what happens. In the space below, record your observations. These observations might be notes, drawings, or both. Be as complete as possible.
1B. What is this movement called?
1C. To view the digestive tract, place a fed planarian under a microscope on a piece of filter paper on top of a frozen spring water petri dish. Draw what you observe.
2A. What happens when you shine a light on the planarian?
In a darkened room, shine a bright, focused light onto a Petri dish containing planarians. The light should not cover the whole dish, but should be a small “spotlight” in the dish. In the space below, record your observations. These observations might be notes, drawings, or both. Be as complete as possible.
2B. What is this movement called?
3A. What happens when you touch the planarian gently with a toothpick?
Lightly touch a planarian with the round end of a toothpick. In the space below, record your observations. These observations might be notes, drawings, or both. Be as complete as possible.
3B. What is this movement called?
4. Using your observations as data, diagram three simple models for each of the taxes that represent how the planarians move in the manner that they do. For each movement, draw a planarian with a “sensor”, “motor” and wires that connect these two. These diagrams will help you answer the driving question of the lesson.
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