Topic	Time	Illinois Learning Standards	Benchmarks
Source	Objectives	Vocabulary	Materials/Procedure
	Leaf Key	Extensions

Topic:
Using scientific processes/tools including a dichotomous leaf key to solve a problem.

Time:
4 class periods

Illinois Learning Standards:
Applications of Learning:
*Communicating by expressing and interpreting information and ideas.
*Working on Teams by learning and contributing productively as individuals and      as members of groups.
*Making Connections by recognizing and applying connections of important      information and ideas within and among learning areas.

4A. Listen effectively in formal and informal situations.
4B. Speak effectively using language appropriate to the situation and audience.
11A. Know and apply the concepts, principles and processes of scientific inquiry.
12A. Know and apply concepts that explain how living things function, adapt and      change.
12 B. Know and apply concepts that describe how living things interact with each      other and with their environment.

Benchmarks:
Late Elementary
Middle/Junior High

Sources:
Naturescope: Trees Are Terrific!,  National Wildlife Federation
Crime Scene Investigations  Center for Applied Research in Education

Objectives:
1. To learn that a dichotomous key is an important way of classifying observed characteristics of leaves and storing      the information.
2. To compare characteristics of leaves from different trees.
3. To use scientific tools and techniques to gather, analyze, and interpret data.
4. To think critically and logically, to connect the data with a reasonable explanation.
5. To review data, summarize it, and form a logical argument about a cause-and-effect relationship.
6. To present conclusions orally and/or in writing to a group of peers.

Vocabulary:
1. dichotomous - to divide into two parts (from Greek)
2. alternate leaf - one is attached and then the next
3. opposite leaf - a leaf across from another leaf
4. simple - one leaf
5. compound - more than one leaflet
6. lobed - curved like fingers
7. toothed - pointed like teeth
8. pinnate vein arrangement - one main vein with smaller veins extending outward.
9. palmate vein arrangement - more than one main vein extending from the base of the leaf.

Materials/Procedures:
Kid Key (Sketch it on a bulletin board or make an overhead transparency-p. 20 Trees Are Terrific)
Part I. Keying Out Kids
1. How do you tell people apart? Physical characteristics like sex, hair color and texture, eye color, height help you tell people apart.

2. Why not by clothing? It changes and can also be the same for more than one person.

3. Show the Kid Key on the overhead projector and explain that each branch is one physical feature that describe a person. You could put the name at the end of the branch.

4. Activity: Work in pairs. Key out yourself and your partner. Put the name in the correct spot on the large diagram at the end of a branch.

5. If more than one person are found at a single position on the key, what other characteristics could identify them? Short or long hair, light or dark skin, etc. could help identify people.

6. Test the Key by asking someone who doesn't know the kids to come in and "key out" a selected student to determine his or her name.

Part II. Keying Out Leaves
Leaf Key (p. 21 Trees AreTerrific)
Leaf Pictures (p. 22 Trees AreTerrific)

1. The Kid Key is dichotomous and works like the Leaf Key you will use next. It is based on the idea of identifying a leaf by the characteristics that it has or doesn't have. This idea is also behind the computer which works based on a binary number system using 0 and 1. Both are methods of storing information.

2. Give each student a copy of the Leaf Key and the Leaf Pictures Sheet. Discuss the vocabulary at the bottom of the Leaf Key Sheet. Use the Leaf Sheet to discuss example(s) of the shapes and whether they are simple or compound, opposite or alternate, toothed or lobed.

3. Use the Leaf Key to model how to identify the first leaf. Set a time limit and ask them to key out each leaf and identify it.

4. Discuss their answers and any situations where multiple answers are proposed.

Leaf Key:

1. Silver Maple 2. Horse Chestnut 3. Black Walnut 4. White Oak 5. Weeping Willow

6. White Pine 7. Sitka Spruce 8. Choke Cherry 9. Honey Locust

Part III: Leafing the Crime Scene
tree field guides
1 small, leafy branch from each of 9 different trees
2 small, leafy branches from a selected tree type, one for the crime scene sample and one for the      evidence sample.
white paper
crayons

1. Teacher Preparation: The day before the investigation- remove one small, leafy branch from each of 9 tree types and a second branch from the tree you select as the crime scene tree. Place the branches in water. The day of the investigation - label 10 closable plastic bags with truck #1- truck #9 and the final bag "Crime Scene Sample". Remove the leaves from each branch from the crime scene and place them in a truck # 4 bag and in the "Crime Scene Sample" bag. Next, remove leaves from each branch placing the leaves from a given branch in a truck numbered bag.

2. Science Briefing:  Much of the work done in a crime lab is comparing one object to another. For example, a paint chip found on a hit-and-run victim's clothing might be compared to the paint from a suspect's car. Finding a match can help link a suspect to the crime. Plant materials from a crime scene can even be compared with known plant parts. Botanists, scientists who study plants, can be called upon to identify a tree from its parts, such as bark or leaves. This then can be used as evidence in court to help a judge or jury decide about the guilt or innocence of a person charged with a crime.

3. The Problem: The Masons were robbed last night and one of them gave these observations to the police:

"I was sleeping soundly when I heard a truck noise outside. The clock said 3:22 A.M. I threw on a robe and ran to the front door. As I opened it, I saw a green, extended-cab pickup truck back into a tree next to the driveway. I couldn't see the license plate because it sped away after hitting the tree. All I saw was that it was the color of our local plates and leaves and limbs were knocked from the tree. I'm sure some of them fell into the back of the truck. I don't think the impact made any dents on the truck because of the rubber bumper."

     Detectives felt that the tree could be a valuable clue for solving the crime. They got the names of all local owners of green, extended-cab trucks and visited each one looking for evidence. Each time leaves were found, they bagged and labeled them truck #1 - truck #9.
     The investigators need some help identifying these leaves. You can help decide if the leaves on the Masons' damaged tree match leaves found in the back of any of the nine trucks. In groups of two or three, use the scientific process to gather and interpret the data. Plan a presentation to the whole group that involves all group members. Be sure to include the following and any other things that will convince your peers that you've done the best job on this case:
Use the key, field guides, resources, and observations of samples to gather data on the leaves.
Organize the observations from each truck sample in a chart.
Interpret the data to determine which truck sample matches the crime scene sample.
Make a reasonable argument using data (reasons, observations, visuals, numbers) for support.
Your written lab report should include a chart of observations, your argument, and the support for your argument.
Each group will present their findings to the whole group in any way they choose with a time limit of 3 minutes.
Hint: In order to preserve the evidence, (Leaves get dry and brittle.) make a leaf rubbing of each leaf on a piece of white paper. These can also be a part of your report.
To make a leaf rubbing: 1. Put the leaf on the desk and cover with white paper. 2. Peel the paper from a crayon, lay it on its side on the paper, rub across the leaf until the whole thing is exposed in the rubbing.

Extensions: Consider the Following:
1. There are also keys for wildflowers, birds, shrubs, fish, and other living things. Use one to key out 10 things.

2. Make a key for any group of objects you want to classify - these nine leaves, a collection of seashells or anything else, a sports team, a sport, etc.

3. Why is it a good idea to make leaf rubbings?

4. Was the leaf from the crime scene a palmate or pinnate leaf? Which were more common (use numbers)?

5. Draw a Venn Diagram to show how the leaves you observed were the same or different.

6. What does a botanist do?