Lesson Plan

Symbiotic Relationships

Students will learn about the 3 types of symbiotic relationships and how populations of organisms are affected by symbiosis.
Jamie K.
Classroom teacher
Highlander Way Middle School (Howell, MI)
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My Grades 6, 7
My Subjects Science

Students will be able to...

describe the 3 types of symbiotic relationships.

provide examples of each type of symbiotic relationship.

describe how common patterns of relationships among populations of organisms are affected by symbiosis.

Grades 6 - 7
All Notes
Teacher Notes
Student Notes

1 Hook

Activity: Exploring

Each student is given a picture of a symbiotic relationship.  They are asked to observe the picture, think about and record your ideas on the following questions: 

1) What organisms are interacting in the picture?

2) How are the organisms interacting?

3) Is the relationship positive or negative?  How do you know? What can you infer from the picture?

4) How do you think the relationship affects the populations of organisms?

After students record their ideas about their picture, they switch with a partner and repeat the procedure with the new picture.

When students have observed both pictures they compare their ideas.

2 Direct instruction

Activity: Conversing

Bring students back together as a whole group.  Ask volunteers to share their picture and how they answered the questions.

Select students who have different types of symbiotic relationships. (parasitism, commensalism, and mutually beneficial)

Ask students how the relationships were the same/different.  Why did organisms interact?  Were all of the relationships postitive? Negative?

Ask students if anyone knows what the word symbiosis means.  Have we ever heard of the terms parasitism, mutualism or mutually beneficial, or commensalism?  What do we know about the concepts?

Place charts with the following symbols in 3 different areas of the room: (++)   (+0)   (+-).  Walk to the ++ sign.  Explain to students that one type of symbiotic relationship is one that allows both organisms to benefit.  Walk to the +0 sign.  Explain to students that one type of symbiotic relationship has one organism benefit and one is not affected.  Walk to the +- sign.  Explain to students that the last type of symbiotic relationship has one organism benefiting and one is harmed.  Ask students to look at their pictures. Which relationship is yours?  Ask students to place their picture under the heading they think represents their picture.  


3 Direct Instruction: Video clips on symbiotic relationships

Activity: Assessing

Ask students to divide their journal page into 3 columns. Ask students to title the page symbiotic relationships. Ask them to label one column ++ both organisms benefit, label the second column; +0 one benefits and one is not affected, and the third column label +- one organism benefits and one is harmed. 

Explain to students that they will be observing videos of the 3 different types of symbiotic relationships.  In their journal, explain to them that they should record at least 1 example for each of the different relationships they observe.  Note which organism benefits, is harmed or is unaffected.

Use the classroom computer to project the following site: http://www.vtaide.com/png/symbiosis.htm

Ask students to take a minute to read through the paragraph at the top of the site and the headings for each of the sections present on the site. Ask students to give a brief definition for the word symbiosis and have them place a new term at the heading of each section of their journal that identifies each of the 3 relationships: mutualism, parasitism, commensalism. Ask a few volunteers how they identified each section.

Select one video from each section to share with students. Take time after the clip to see under which heading they classified the relationship and why.

4 Independent Practice

Activity: Reading

Send students home with the edhelper.com article titled, Symbiosis.  Ask students to read through the article and answer the questions that follow.  Remind students that we will be discussing the article when they come back the next day.

5 Homework review-vocab cards for each type of relationship

Activity: Creating

Journal write: when students come into class ask them to take out their edhelper article, 'Symbiosis'.

Ask students to review the term symbiosis, mutualism, commensalism, parasitism with a partner.

Students will be creating Frayer models for each of the terms.  Have students draw a large box in their journal.  Ask them to divide the box into 4 parts.  Ask students to write the name of the term in the center of their box. In the top left corner they will be describing the concept.  In the top right corner they will be adding something that will help them remember the concept.  In the bottom left corner, students will draw a picture to help them remember the concept, and in the bottom right corner they will give an example of the term.

With a partner have students complete the description for each concept.

6 Gathering new information

Show video clips on the different symbiotic relationships.  Stop and discuss the relationship, if it is mutualism, parasitism, or commensalism.  Have students add new information to their Frayer models.

Other video links can be found at: http://www.vtaide.com/png/symbiosis.htm

Have students complete their Frayer Models on each of the terms: symbiosis, mutualism, commensalism and parasitism.


7 Assessing prior knowledge

Activity: Assessing

Review the terms symbiosis, mutualism, commensalism, and parasitism with students.  Have a few volunteers provide examples and descriptions from their Frayer models.

Have students take a walk around to their original classification of the pictures of the symbiotic relationships.  Ask them to check the pictures to make sure they are placed under the correct heading.  If they think their picture needs a new location have them post it under the heading that best fits that relationship.

Debrief the classification with students.

8 Performance Task

Activity: Assessing

Provide students with a set of 6 cards.  Each card has a picture and a description of the relationship.  Ask students to classify each of the pictures and give evidence as to why they believe that picture represents that symbiotic relationship.  Ask students to describe one example of how populations of organsims are affected by symbiosis.