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The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

INTRODUCING THE ACTIVITY

1) “Step into the circle if” about solving mysteries: Gather students in a circle and step into the circle if the statement applies to them, then step back out.

• You’ve ever watched a detective show or movie.
• You’ve ever lost something & tried to figure out where it went.
• You’ve heard the word “evidence” (ask them to define it)
• You know what a “suspect” is (ask them to define it)
• You’ve ever tried to figure out a mystery (ask few to share)

2) Explain that they’ll be trying to solve a nature mystery. Tell students that they’ll be acting as detectives today, trying to explain a nature mystery based upon the evidence they find.

3) Hike for a few minutes towards the ‘Cedar Pass Through’. Ask students to find a leaf on the ground. At a clearing, circle-up the group. Introduce a tool & skill needed to help them solve today’s mystery: the hand lens & making observations. Hand out the hand lenses & have students find the ‘sweet’ spot’ (the position of the lens where the leaf is crisp and clear). Introduce how to make observations (“I notice”). Ask students to share an “I notice” statement about their leaf.

4) Continue hiking to the decomposing log, & unveil the mystery – “The Case of the Disappearing Log.”
This log used to be a tree. People have been noticing that it, and other logs in the area, is slowly disappearing! It will be your job to figure out what’s happening to the log.

The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

INITIAL EXPLORATION

1) Explain that they’ll explore and observe the log together, looking for evidence that the log is disappearing.

2) While students explore, model & encourage making observations & asking questions (inquiry).

3) If students are losing interest, suggest that they change their perspective.

The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

INITIAL SHARING

1) Bring group back together & tell students to share observations & evidence in pairs.

2) Ask a few students to share their observations with the whole group.

3) Help students make connections between cause & effect when discussing evidence of the disappearing log.

4) Ask students to ‘Turn & Talk’ about possible explanations for what might have caused the evidence they observed.
Ask a few students to share out explanations

The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

MEET THE SUSPECTS

1) Give each student either an “Evidence” or a “Suspect” card.

2) Tell Evidence card holders to stay put, while Suspect card holders move around looking for a match.

3) Once pairs have found each other, tell them they should share their cards out loud with each other.

4) Matched pairs mingle & introduce themselves to other evidence/suspect pairs.

The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

INVESTIGATING WITH A KEY (bring group to another large log, or tell each team to choose their own log in a designated area)

1) Tell students they will learn more about possible causes of evidence they have found.

2) Explain they’ll use a key to identify suspects & connect them with evidence.

3) Demonstrate how to use the Disappearing Log Key.

4) Students use the key in teams to figure out what suspects caused the evidence on the log.

5) Encourage students to look for evidence of where the tree stood, make possible explanations for how it fell, & the order of suspects & events that impacted the log.

6) Circulate, trouble-shoot, be a co-investigator, and ask questions.

The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

DISCUSSION EXPLANATIONS

1) Gather group & ask each team to share their explanations with another team.

2) Ask a few volunteers to tell the whole group their explanations & the sequence of what happened to the log.

3) Encourage respectful disagreement & ask for alternative explanations.

4) Focus the discussion on the relationship between suspects and the environment of the log. Ask:

• How many different organisms can you think of that might have benefitted from the log you investigated?
• What do organisms that are breaking down the log get from the log?

5) Point out that scientists have conversations like this to come up with best explanations.

• The point of science is to come up with explanations based upon all available evidence. Scientists need to be open to different explanations, and to think critically about each explanation.

6) Describe how thinking about cause & effect relationships helps us to understand what has happened by developing possible explanations.

• Just like scientists, you observed evidence of what has happened, then made possible explanations for what caused the effects you observed.
• Scientists use the idea of cause & effect to make explanations in all areas of science.

The Learning Events should always be prefaced by focusing on the essential questions:

• What is a living organism?
• What do all organisms need for survival?
• What adaptations help the organism survive in its environment?
• What interactions do you observe –between organisms, and between the organism and environment?
• How am I connected to the organism(s) I’ve experienced during field studies?
• What does it mean to be a steward of the environment?
• What is a system?
• What does it mean to think using a systems approach?
• How have I experienced ‘Systems’ at ODS? (e.g. in what ways is a disappearing log a living system?)
• How am I connected to ‘Systems’ in my everyday life?

WRAPPING UP – REFLECTION

1) Return the students’ focus to the “Case of the Disappearing Log.”

• What happened to the rest of the matter in the log? Where is the missing wood now? Where could it have gone?

2) Suggest that some things that happen in nature don’t always leave behind observable evidence.

3) Briefly discuss what decomposers do with matter from the log (relate to body systems).

• Decomposers consume food & nutrients from the wood for the purpose of their own survival (i.e. to run their own body systems):
• Banana slugs feast on dead leaves & debris from the forest floor. Slugs use a tongue (rasping radula) covered in 27,000 teeth to scrape off pieces of live and dead plant tissue, fungi & bacteria.
• A slug has two adaptations that allow it to live on land: 1) It carries its aquatic environment in the form of slime. The slime covering keeps the skin from drying out. Slime is toxic, and give protection from predators. 2) Slugs don’t have gills, but uses a fleshy compartment that looks like a hump or shoulder (called the mantle) to act as a lung. There is a pore on the right side of the mantle through which air circulates. The breathing hole can open and close & is called a pneumostome.
• Banana slugs move along using a muscular foot to crawl along forest floor, on plants & trees.
• Banana slugs use sensory tentacles to feel their way about & for smelling. Eyes are on the ends of tentacles. They don’t see in detail, but can sense the intensity of light. The tentacles can move about so the slug can see in all directions. If the slug senses danger it can pull these tentacles in to protect the eyes. If a predator bites off a tentacle, the slug can grow a new one.
  Banana slugs are hermaphrodites –organisms that contain both male & female reproductive organs.
• Fungi – look like plants but are heterotrophs, like animals. Fungi are parasites –organisms that live in or on another organism (its host) and benefits by deriving nutrients at the host’s expense. A fungus must digest food to live, while plants make their own food through photosynthesis. Fungi contain mycelium (threadlike filament) which grows inside the tree, slowly breaking it down. Unlike animals, fungi don’t digest food internally. They secrete digestive enzymes so that their food is “digested” outside of their bodies. A fungus then acquires its nutrients by absorption of the digested food through the mycelium. Fungi use asexual reproduction, via spores. Bracket fungi are the fruit of a much larger fungus.
• Mosses (bryophytes) Trees are covered in mosses. Mosses do not have large stems or a trunk to help them grown upwards, they must grow on solid surfaces, like rocks, compact soil or wood. They also do not have flowers or seeds, relying on water or high moisture to reproduce and disperse.
• Lichens can be found on trees and rocks in the ecosystem.

4) Reveal that the matter in the log didn’t actually disappear – -it just changed its form!

• Scientists know that matter can’t be destroyed, or disappear into nothing!
• We do know that matter can change its form – going between solid, liquid, and gas –and that gases can be invisible.

5) Explain where the matter goes & why it is important for ecosystems.

• Decomposers are important to ecosystems because they make matter available to plants, which is an important part of matter cycling through ecosystems.

6) Tell students to keep looking at the other wood in the forest along Cedar Grove for more mysteries & evidence. Locate a Culturally Modified Tree (Suspect: Coast Salish Peoples), Stumps (Suspect: Human), Big Snag (Suspect: Lightning), fallen tree with exposed roots (Suspect: Wind).

7) Walk & Talk questions (in pairs) or final circle:

• What are some questions you have about decomposing logs & the organisms that decompose them?
• What other evidence would you like to explain this mystery?
• Could humans be considered decomposers? Why or why not?
• What helped you learn today?
• In what ways is a disappearing log a living system?

8) Walk & Talk application question: Tell students to imagine they’re back at home and their family is worried that your house has some kind of infestation/the wood seems to be decaying. Ask students to discuss with a partner:

• What evidence would you look for to figure out if the wood is decomposing?
• What might the organisms be in the wood of your house?

9) Revisit the Essential Questions