SILC Lesson Template
Science Inquiry
Name of Lesson/Unit: Explore Dichotomous Key
Subject Area Focus: Life Science
Grade Level:
Prepared by: Erinne Ark
*Overview
& Purpose/
Essential
Questions
Middle School
This is a tiered lesson introducing the different dichotomous keys and the way in
which they are used in life. This is an inquiry lesson that explores the dichotomous
key in life science at the 7th grade level. Students will explore simple and complex
dichotomous keys and create their very own.
Essential Question: How and why do we use dichotomous keys?
*Materials
•
•
•
Candy (5 different types according to the candy dichotomous key)
Examples of field guides
Copies of worksheets needed to do lesson (attached)
*Time Required
2 – 3 class period lesson (45-50 minutes)
*Essential
Understandings
*MT State
Content
Standard(s)
S3.5.gr6-8.C
Create and use a basic classification scheme to identify plants and animals.
Montana Content Standard 1 (Students, through the inquiry process, demonstrate
the ability to design, conduct, evaluate, and communicate results and reasonable
conclusions of scientific investigations.)
Montana Content Standard 3 (Students, through the inquiry process, demonstrate
knowledge of characteristics, structures and function of living things, the process
and diversity of life, and how living organisms interact with each other and their
environment.)
*Background
Information
Utilize this lesson while studying Diversity of Life and, more specifically,
classification of living things.
*Primary
Learner Results
•
•
•
Students will incrementally explore dichotomous keys/field guides
Students will be able to use a dichotomous key
Students will recognize a dichotomous key/field guide
Additional
Learner Results
As appropriate….always room for additional learner results.
*Technology
Connection
(encouraged)
- Students may use computer software to make class dichotomous key
- Teacher may utilize Smartboard or overhead projector to show different
dichotomous key examples
Adapted from Georgia Department of Education
January 2010
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*Procedures
Step 1
Description: Walking into the classroom & Discussion
1)
2)
3)
As students walk in have them grab two different pieces of candy out of the candy bowl that
is in the classroom or being held for them as they walk in.
Students need to have their desk clear with only a pencil and the candy that they received
when they walked into the room.
Show the different types of field guides and ask students if they know what these types of
books are (looking for the answer of field guide or even dichotomous key).
Duration
Step 2
Description:
4)
5)
6)
7)
Hand out the dichotomous key for the candy and see if students can figure out the scientific
name for the two candies in which they received.
Once most of the students have figured out the key and the scientific name for the candy,
have 5 different students explain their candy’s scientific name and how they figured this out
(one student for each different type of candy). They can then eat one piece of candy for
correctly identifying their candy.
Hand out another example of a dichotomous key (Key to Dicotyledonous Families) and
discuss how this one is different from the others.
Discuss why scientists might use a dichotomous key…….two different choices, used to find
names of things, use to find if they can eat something or not, figuring out what type of
animal it is, etc…..are some of the ideas that they might come up with.
Duration
Step 3
Description
8)
9)
Hand out six different strips of paper – each has colored pictures of a Noxious Weeds of
Montana on it. And hand out the dichotomous key for figuring out what these six weed
names are. Students will put answers on the key itself. This activity can be done in groups
of 3-4.
Teacher can walk around room to check answers to the weed key. When the group has
answered it correctly they can then eat their last piece of candy.
Duration
Step 4
Description: Challenge
Adapted from Georgia Department of Education
January 2010
Page 2 of 3
10)
11)
12)
Hand out the pond black and white picture of pond life and the dichotomous key that goes
with it. The challenge for this activity is to see how many they can type correctly. This is a
challenge sheet – so I made it fun with a bit of competition.
Talk about the progression of the dichotomous keys….from 5 candies and actually being
able to see and feel them, to colored pictures of 6 weeds, to 45 pond creatures and in black
and white. Discuss the difficulties associated with typing classifying the pond creatures.
The next day give the students the answer to the pond creature key and see how many they
got correct. Discuss any issues that may have arisen while completing this key.
Duration
Extension
- Students can create their own dichotomous key of their homeroom class picture
(this worked very well because pictures were just handed out the day before).
- Take class outside and utilize the local dichotomous key for the area and identify
plants/animals in the area.
*Assessment
*Resources
-
Assess as you are walking around to different groups with discussion and
by looking at how they are utilizing the dichotomous key to figure out the
Noxious Weeds of Montana.
-
(Extension assessment) Students will create a dichotomous key of the
people in their class (utilizing the class picture)
Knoweeds
http://plants.usda.gov/index.html
http://www.mtweed.org/library/index.php/knoweeds-k-12-noxious-weedcurriculum/
Adapted from Georgia Department of Education
January 2010
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