Lesson Description

This lesson introduces learners to the differences and similarities between brown rot and white rot. Learners will learn how to recognize signs of brown rot and white rot in wood in a natural environment.

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Associated Standards

K-2
CCSS.ELA-LITERACY.SL.2.2
Recount or describe key ideas or details from a text read aloud or information presented orally or through other media.
 
CCSS.ELA-LITERACY.SL.2.3
Ask and answer questions about what a speaker says in order to clarify comprehension, gather additional information, or deepen understanding of a topic or issue.

3-5
4LS1-1 From Molecules to Organisms: Structures and Processes
 
CCSS.ELA-LITERACY.SL.3.1 (also SL.4.1, SL.5.1)
Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 3 topics and texts, building on others' ideas and expressing their own clearly.
 
CCSS.ELA-LITERACY.SL.3.3
Ask and answer questions about information from a speaker, offering appropriate elaboration and detail.

6-8
CCSS.ELA-LITERACY.SL.6.2
Interpret information presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how it contributes to a topic, text, or issue under study.
 
MS-LS1-4 From Molecules to Organisms: Structures and Processes
Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants respectively.

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Essential Questions
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• How do fungi break down wood?​
• What are saprophytes?
• What is brown rot?
• ​What is white rot?

Enduring Understandings

• Fungi break down wood by digesting cellulose and lignin. Cellulose is a relatively small, simple molecule, whereas lignin is a big molecule and harder to break down.
• Saprophytes get their energy from breaking down dead things. They are also called decomposers.
• Brown rot represents different types of fungi that breaks down cellulose in wood, leaving behind a brown blocky appearance in the wood.
• White rot represents different types of fungi that breaks down both cellulose and lignin in wood, leaving behind a white stringy appearance in the wood.

Learning Objectives
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• Learners will correctly identify brown rot and white rot in samples of decomposing wood.
• Learners will explain why brown rot and white rot leave their characteristic appearances in wood.
  
• Learners will define the term saprophyte and identify other saprophytes beyond brown rot and white rot.
  

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Materials

• Paper
• Writing utensils
• ​Magnifying glass or loupe
• Examples of brown rot and white rot affected wood

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Lesson Instructions

1. ​​Anticipatory Set:
   1. Have examples of brown rot wood and white rot wood available for learners to examine and deconstruct while they wait for the lesson to begin.
2. Ask learners what they notice between the different types of wood that they examined.
3. Explain that each of the different pieces of wood show signs of different kinds of decomposition, or rot, caused by fungi. The wood that appears blocky and brown or red has been affected by brown rot, while the wood that appears white and stringy has been affected by white rot. The reason that brown rot looks blocky is that brown rot can only break down the simplest components of the wood, cellulose, but is unable to break down much of the more complex components of the wood. The reason the white rot looks white and stringy is because white rot can break down both simple (cellulose) and complex (lignin) components of wood, leaving it very frail, white, and stringy. Both white rot and brown rot are examples of saprophytes, or decomposers. Decomposers are extremely important for ensuring that our soils stay healthy, that plants can keep growing, and that our world isn't overrun with dead stuff and trash!
   1. If giving this lesson after reading A Toadstool's Treasures, reference the part of the story where Molly, Phoebe, and Brother Toadstool experience the forest without decomposers. Explain that brown rot and white rot fungi are some of the main fungi that disappeared in the story!
4. Test your learners' comprehension by telling them you are going to quiz them by holding up a piece of wood and asking whether there are signs of brown rot or white rot. Choose several good examples of wood primarily dominated by either brown or white rot, but also try to include at least one example where there are clear examples of brown rot and white rot on the same piece of wood. Then explain that these different kinds of fungi are always working together.
5. Explain to the learners that they will now have the chance to identify signs of brown and white rot in the wild on an interpretive hike! Each learner must find at least one example of brown rot and one example of white rot during the ten minute hike. Then once they get back, learners will share what they found and create an exhibit for the classroom/home.
6. After the hike, bring learners together into a circle and ask them whether they saw more brown rot or more white rot. What else did they notice during the hike? Did they notice signs of any other organisms responsible for decomposing things (like bugs or mushrooms)?

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References and Resources

​Our lesson plans utilize the backward design model presented by Understanding by Design by Grant Wiggins and Jay McTighe

Example of Brown Rot

CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1098816

Example of White Rot

By Auró - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=46955258

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