Investigation 4 - Our Nearby Ecosystem

Overview: In this 4-5 day investigation, students prepare for fieldwork and then go into the field to practice and apply some of the skills and knowledge that they developed while solving the sea otter mystery. Depending on local opportunities, the field trip may take the form of an ecosystem mapping exercise, a river or stream walk, or a coast walk survey. Students return to the classroom to analyze and share their data after the field trip.

Focus Question:

• What are the elements of this aquatic ecosystem?

Engagement: (1 - 2 class periods)

Brainstorm what students may find on the field trip. Talk about ideas, questions, predictions of what lives there. Discuss what creatures may be a part of this ecosystem, and make a list of potential living creatures to count and on which to collect data.

Remind students of the "e" activity that they did in investigation 2, and tell them they will be doing some sampling on the field trip. Talk with students about the selection of sampling locations.

Why would scientists choose random locations instead of just picking a place that looks good? (Otherwise they might pick a place with unusual abundance or a place that is easy to count, and their data might not be accurate.) One way to select random sites is to toss the quadrat and count wherever it lands.

Why is it important to take more than one count? (It is important to have at least three different counts of each thing that you are samplingbecause each count is such a small sample of the larger area you are trying to describe.)

Discuss the importance of the aquatic ecosystem to people in your area, and field-trip etiquette.

Exploration: (1 extended session)

Part 1 (45 minutes)

Allow students time to freely explore the field site for the first half hour after they arrive. Then come back together and draw a map of the field site (beach, river, pond) in science notebooks.

Part 2 (60 minutes)

Discuss what the students saw. Explain that they will do some counts, using a quadrat, in small groups at different parts of the beach (or river bank, pond, etc.). Each group will have the opportunity to report to the whole group in a scientific conference after they get back to the school. They will have time to explore all quadrats after the count.

Generate questions that will stimulate counting or comparing (i.e., how many urchins will I find in a tide pool?, how many rocks bigger than a fist will we find on each part of the riverbank?). Agree on the question(s) to be answered and the item(s) to be counted. Create a data table in notebooks.

Choose and assign sampling areas as randomly as possible. If possible, each student group should count one thing in three different locations in a random manner by tossing the quadrat over their shoulder. However, if time is an issue, you might assign three different groups to take one count each of the same thing using the same method to set the quadrat count area.

Conduct the counts, using a quadrat, and record data in notebooks.

Part 3 (20 minutes)

When counts are completed, each student should use a hand lens to draw a closeup of one organism in the ecosystem.

Allow students to rotate to different quadrats and observe.

Explanation: (1 - 2 class periods)

Students come back to the classroom and share findings from their quadrat counts and observations.

Data from the three (or more) sampling locations should be averaged.

Gather students together for a "scientific conference." Students will act as the groups of "scientists" who will report on their findings to the rest of the group. It is fun if the teacher and any assistants can be quirky conference reporters during this conference, so that key questions can be asked to the scientists: "How did you come up with these findings?" and, to a member of the "audience": "How would you have gone about answering this question?" In particular, it is key to prod students to ask and answer their own questions about the data they are collecting. Why might community members be interested in learning about our data?

This activity helps to emphasize that scientists are just everyday people who have questions and try to get the answers to them. It also emphasizes that sometimes you can begin with a hypothesis, and over time the hypothesis can change with more observation or knowledge, because oftentimes it happens during the activity itself. You can also stress the importance of sharing scientific knowledge within, not only the scientific community, but also with the entire community.

Extension (Application): (30 minutes)

Analyze the data that the groups presented. What do we know about our ecosystem that we didn’t know before? What are some ways we observed that different elements of this ecosystem are interconnected? How do they depend on each other?

Evaluation:

Formal Evaluation will be done at the end of the unit.

Teacher Preparation

1-3 hours for field site selection, research, and trip logistics.

Alaska Science Grade Level Expectations Addressed

The student develops an understanding of the processes of science by:

The student will demonstrate an understanding of the attitudes and approaches to scientific inquiry by:

The student demonstrates an understanding that interactions with the environment provide an opportunity for understanding scientific concepts by:

The student demonstrates an understanding that all organisms are linked to each other and their physical environments through the transfer and transformation of matter and energy by: