Biology

Standard 1: Objective 3

Title: Symbiotic Relationships

A Brief Description: Students are introduced to symbiotic relationships between living things. They then create their own examples of imaginary symbiotic relationships.

Materials needed: 12 handouts(see below) handouts need to be cut into 3 sections so that there are 36 strips, 12 commensalisms, 12 mutualisms and 12 parasitisms, paper and pencils

Prior to Assessment: No knowledge needed

Time Needed: 1 class period

Teacher Procedures:

  1. Have picture or specimen or a strange parasite for students to examine. ( ie. Leech, jar full of mosquitoes)
  2. Pass the specimens or pictures around the class and let students observe.
  3. Ask the students if they know what the organism is or what role in an ecosystem it plays.
  4. Lead students to a discovery of the meaning of the word symbiosis..
  5. Have students get out a blank sheet of paper and title it: Symbiotic Relationships
  6. Randomly pass out the slips of paper made previously
  7. Instruct each student to follow the directions contained on the slip of paper they receive. They should complete the first part of this assignment on their own.
  8. You might encourage students to use their books as a resource if they are having difficulty.
  9. Next have students mingle and share their examples and write down an example of the two remaining symbiotic relationships that they learn from each other.
  10. Divide students into groups of 3.
  11. Instruct students they should now use these 3 terms and create analogies that apply to them in their relationship with other people
  12. Present students the following example:
  13. Sara is trying out for the Alta High cross-country team. She thinks Matt is pretty cute. Matt is trying out for the Alta High football team but is still a little scrawny. Because Sara thinks Matt is so cute she bakes him cookies and brings them to his house every day. Matt thinks Sara has got to be the greatest girl in the world, so he invites her to run with him every afternoon. Matt is gaining weight from the cookies and Sara is increasing her daily milage by running with Matt. This is a mutualistic relationship.
  1. Students should be given time to generate these. Impress to students their examples must be as detailed as the example you gave them.
  1. Let each group share 1 or 2 scenarios they have written. Have class members guess what type of relationship it represents.
  1. Ask students to brainstorm other relationships besides symbiotic, that organisms share in nature. (eg. Predator-prey, competition)

Handout:

Commensalism

Definition:Commensalism, one organism benefits from a close relationship between two organisms, and the other organism is not harmed by the association.

Example: As a human being you have living on you millions of microscopic mites. Some live at the base of your eyebrow hairs, others on your eye itself. You can’t see these without a microscope and everybody has them, no matter how many showers you take.

Directions: Come up with one example of commensalism in nature. Also use your imagination and create a commensal relationship between two imaginary organisms.

Mutualism

Definition: Mutualism is a close relationship between two different organisms from which both benefit.

Example: Our digestive tracks are home to millions of bacteria cells. These microorganisms live inside of us. They help us obtain the vitamins we need to survive. Without them we would be very sick.

Directions:Come up with one example of mutualism in nature. Also use your imagination and create a mutualistic relationship between two imaginary organisms.

Parasitism

Defintion: Parasitism is a close relationship between two different organisms where one organisms benefits and the other is harmed from the association.

Example: The tarantula hawk wasp is an example of parasitism. The wasp lays its eggs in the abdomen of the tarantula. The tarantula is eventually eaten by the growing wasp larvae.

Directions: Come up with one example of parasitism in nature. Also use your imagination and create a parasitic relationship between two imaginary organisms.