Symbiosis: Relationships Among Organisms

Objectives:

• Students will be able to define symbiosis.

• Students will be able to define mutualism and identify examples of this type of relationship among organisms.

• Students will be able to define parasitism and identify examples of this type of relationship among organisms.

• Students will be able to commensalism and identify examples of this type of relationship among organisms.

Suggested Grades:

4th Grade - 5th Grade - 6th Grade

Lesson Procedure:

Print the reading comprehension worksheet passage and questions (see below).

Students should read the passage silently, then answer the questions. Teachers may also use the text as part of a classroom lesson plan.

Lesson Excerpt:

In nature, certain organisms have relationships with other organisms that benefit one or both of the organisms involved. This type of relationship is known as symbiosis. Symbiotic relationships can last a long time. There are several different types of symbiosis. One type is known as mutualism. This is a relationship that is good for both organisms. In other words, one could not survive without the other. An example of mutualism is the relationship between the yucca moth and the Joshua tree (also known as the yucca plant). When the plant blooms, female yucca moths can be seen flying from flower to flower.

The moths pick up pollen and roll it into a ball in their mouths. They then inject their eggs into the ball of pollen. Then they make a hole in another flower and pack the ball of pollen into the part of the flower that contains its reproductive parts. The moth has protected its eggs from predators and helped to pollinate the flower at the same time. The pollinated flower can now make seeds. Some of the seeds eventually sprout into new yucca plants. Other seeds provide food for newly hatched moths when the eggs hatch into larvae.

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