In Lesson 7, they observe how the frogs and crabs interact with the living and nonliving elements in the habitats. In addition, students have an opportunity to answer some of their own questions about the animals and to exchange information with each other in a class science meeting.

Lessons 8 and 9 introduce the third animal, the millipede. Students repeat their activities from Lessons 3 through 6. As they compare and contrast the frog, crab, and millipede, students focus on such habitat conditions as climate, moisture, other living things, and light.

Now that students have collected a great deal of data in their animal logs, they are ready to discuss this information and identify some of the daily behavior patterns of the three animals. To link the animals’ behaviors to the conditions in their habitats, students conduct a simple experiment that tests the animals’ reactions to a change in light. Students compare the animals’ behaviors during the experiment with their behaviors under normal conditions and suggest reasons why the animals responded as they did.

In Lesson 11, students begin to study the fourth classroom animal: the human. They discuss the habitats in which this animal lives, its survival needs, and its structures and behaviors. This activity lays the groundwork for later lessons in which students will discover that humans can take steps most other animals cannot in order to meet their needs.

Having spent much time observing and discussing the four animals as each relates to its habitat, students are ready for the embedded assessment in Lesson 12. Students move from making general observations on all the animals to observing one specific behavior of one animal. Having read about how researchers study a specific dolphin behavior in Lesson 5, students now develop a research question on one of their three animals. They also develop behavioral observation guidelines that will help them answer their research questions. Through this process, students apply their understanding of key skills they have been developing throughout the unit, such as gathering information by observation, using observation logs, and discussing data with peers.

While students’ work on the research projects proceeds, the class compares and contrasts the animals’ structures and behaviors in Lessons 13 through 15. In so doing, students discover how an animal is suited to life in its particular habitat and why most animals would not survive as well in a habitat with vastly different conditions. Students also read about hard-to-observe characteristics of the frog, crab, and millipede and about the beaver, which like the human, can alter its habitat to meet its needs.

In Lesson 16, students present their research results to the class. By discussing results with peers who have researched the same behavior, students further recognize the importance of sharing research findings within a scientific community. Lesson 17 is a post-unit assessment that is matched to several assessments in the first few lessons. The Additional Performance and Self-Assessments (see Section 5) provide further questions and challenges for evaluating student progress.

This is a challenging unit for students. They are responsible for the care of three different animals. They collect information on each animal through firsthand observation and research. As students apply this information to compare the animals’ lifestyles, they develop an understanding that most animals are suited to life in a particular habitat. Students begin to become aware that the diversity of life is directly related to our planet’s various environmental conditions. They recognize the ways animal life is adapted to those conditions. Students also begin to see that learning about animals involves long-term observation of the animals both in nature and under the care of humans.