Case Studies as Opportunities for Inquiry: Improving on Nature?

Activity Overview and Purpose:

In “Improving on Nature?” students investigate the role of human activity on energy flow in ecosystems. Embedded within this activity are a variety of nature of science tenets. After being put into three groups (each with its own perspective/role), students are provided with preliminary data and information about the proposed 1958 introduction of the black bass into Guatemala’s Lake Atitlan. Students use this information to make an initial judgment on the proposal. As more historical data is provided, students reorganize into jigsaw groups to discuss and analyze the aftereffects of the species introduction. This activity is highly modifiable and can be used to discuss bioethics, artificial selection, and historical perspectives in addition to or instead of the highlighted energy and NOS slants.

Standards:

Virginia SOLs:

BIO 1: The student will demonstrate an understanding of scientific reasoning, logic, and the nature of science by planning and conducting investigations in which

a)observations of living organisms are recorded in the lab and in the field;

e) conclusions are formed based on recorded quantitative and qualitative data;

g) validity of data is determined;

j) research utilizes scientific literature;

k) differentiation is made between a scientific hypothesis, theory, and law;

l) alternative scientific explanations and models are recognized and analyzed; and

m) current applications of biological concepts are used.

BIO 7: The student will investigate and understand how populations change through
time. Key concepts include

a)how genetic variation, reproductive strategies, and environmental pressures impact the survival of populations;

b)how natural selection leads to adaptations;

BIO 8: The student will investigate and understand dynamic equilibria within populations, communities, and ecosystems. Key concepts include

a)interactions within and among populations including carrying capacities, limiting factors, and growth curves;

b)nutrient cycling with energy flow through ecosystems;

c)succession patterns in ecosystems;

d)the effects of natural events and human activities on ecosystems

Aspects of Inquiry:

  • Research question: How will the introduction of an alien species affect energy flow in the Lake Atitlan ecosystem?
  • Data analysis: Students analyze the initial data provided in Interest Briefings, Students analyze data in historical updates

Nature of Science tenets embedded within the lesson:

--Scientific knowledge is tentative and changes in light of new evidence

--Subjectivity plays a role in science

--Science is collaborative and social in nature

--Science is affected by society and culture

Materials:

--“Improving on Nature” Teacher Notes

--“Improving on Nature” Student Background Packet

-- Village Meeting organizer (see attached)

Procedure:

Research Question:

How will the introduction of an alien species affect energy flow in the Lake Atitlan ecosystem?

  • Introduction (10mins):

Teacher asks students to identify things that can affect an ecosystem. If not mentioned, teacher asks students if they think the introduction of a new species has an effect on an ecosystem and, more importantly, why?

Teacher[JSL1]then introduces research question and provides a brief historical background of case (provided in both student and teacher notes) and tells students they will be taking the perspective of one of three “interest groups”:

1) those familiar with recreational black bass fishing;

2) those familiar with the local villages; and

3) those familiar with the Lake Atitlan ecosystem.

(See Student Handout Background Briefings 1-3)

  • Activity Body (60 mins):

A. (15 mins)

Each group uses the data provided to complete four tasks:

--analyze the initial provided data and information

--discuss the proposal that the black bass be introduced into Lake Atitlan to promote tourism and the local economy

--decide whether to support or reject the proposal

--prepare to defend its position in a public forum (see provided support worksheet)

B. (15 mins)

After each group comes to a consensus, the class reconvenes and the “village meeting” is held in which each group presents their side, using their data and findings to support their position. After each side has presented, an open-debate is held.

Finally, students “vote” on the proposal based on what they learned/heard in the meeting.

C. (30 minutes)
Students form jigsaw groups (consisting of at least one member from each original perspective). Once in these groups, the teacher provides them with 7 “Historical Updates” that include new observations and data. (See Teacher Notes)
Students also answer a series of questions included in these updates. (See Teacher Notes)

  • Debrief (20 mins):

Students come back together for a concluding whole-class discussion. The teacher asks students to use the data provided to make conclusions about how the introduction of the black bass impacted energy flow in the Lake Atitlan ecosystem[JSL2].

The teacher also asks if students think that there would be a similar effect if a new species were to be introduced to the Chesapeake Bay. Students are encouraged to think about the complex relationships between organisms in an ecosystem and food web.

Embedded within in this concluding discussion are explicit references to NOS tenets[JSL3]:

--Scientific knowledge is tentative and changes in light of new evidence: How did your opinions change as you were provided with more data? Did you feel more confident in your conclusions as you got more supporting evidence? How can new evidence upturn a previously held belief?

--Subjectivity plays a role in science: How did taking your particular perspective affect how you interpreted the data? Would you feel the same or different if you were taking another group’s perspective?

--Science is collaborative and social in nature: How did the public forum and discussion affect your view and opinion? What is something surprising you learned by working in your jigsaw groups? How did your peers shape your thoughts?

--Science is affected by society and culture: How does your position as an American adolescent affect your thoughts on an issue that takes place in Guatemala? How can political, religious, economical, and philosophical beliefs impact your thoughts on this case?

As a summative assessment, students write a report detailing how they would vote on the proposal should they vote on it tomorrow. Students use the data and arguments raised in the forum to support their vote and references to the nature of science to explain what influenced their decision.

Modifications:

Different slant focuses:

--Bioethics: Teachers can incorporate ethical considerations into the lesson by talking about the various political, economic, and societal factors at play for big business (Pan AM), Guatemala as a whole, and the local village.

--Historical Perspective: How were people shaped by the views of their time? How would this differ from today? What has changed since then?

--Artificial Selection: How did the introduction of the black bass influence the natural factors at work in the Lake Atitlan ecosystem?

Assessment Strategies:

Informal formative: Discussions during group activity, “village meeting” debates

Summative: Student report supporting/explaining their vote.

Source:

Village Meeting Organizer
My Perspective: ______
Will we support the proposal: ______
Pros of the Proposal: / Cons of the Proposal: / Specific supporting evidence/data:

[JSL1]Expected answers?

[JSL2]Expected answers

[JSL3]These are great!