Beacon Lesson Plan Library

Living in Water

Hala Bessyoune


Students perform a lab activity in which they examine the external structure of a preserved fish and find out why fish can survive and live in water.


The student understands the mechanisms of change (e.g., mutation and natural selection) that lead to adaptations in a species and their ability to survive naturally in changing conditions and to increase species diversity.


-Disposable gloves
-Preserved fish
-Dissecting pan
-Paper towels
-Microscope slide
-Dissecting scissors
-Dissecting probe
-Lab directions
-Data sheets (see associated file)


1. Read over procedure
2. Print direction/data sheets, the pre-activity questionnaire and the post-activity quiz. You may choose to print one copy for each student or one copy for each group.
3. Assemble the materials neded for the activity.


1. Introduce the lab activity to your students by reviewing the following points:
-The body of all vertebrates perform certain basic functions and the structures that perform these basic functions tend to be somewhat similar because the vertebrates evolved from common ancestors. In addition each type of vertebrate, including fish, has adaptations specifically suited to the environment in which it lives.
-Tell the students to brainstorm together and find out what other species have adapted/mutated themselves for survival.
-Discuss in-depth with students the mechanisms of change that lead to adaptations in a species and their ability to survive natuarally in changing conditions and to increase species diversity (e.g., mutation and natural selection).
-Discuss with the students the role that the environment and the predators play in species adaptations and survival and give examples ( the Himalayan rabbit's fur color is affected by temprature. Why are the tips of the rabbit's ears darker than its body? Also include the rayfish's ability to change its skin color to escape from its predators.)

2. Divide your students into groups of four.

3. Tell the groups to follow the lab directions and to record their observations on their data sheets.

4. Walk around the classroom and check your students' work. Offer feedback and guidance. Once students have completed the lab and you have assessed their answers, hold a discussion so that those who need to can obtain the correct answers and information.


Assess the completed activity sheet. An answer key is provided in the associated file. Students will need additional feedback and discussion in order to make sure they understand the mechanisms of change that a species undergoes in order to survive.

Web Links

Web supplement for Living in Water
Prehistoric Fish

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