Description:

Homeostasis is the mechanism that maintains balance in body systems. An example of this is the cardiovascular system, in which levels in the cells. Carbon dioxide levels are monitored by the hypothalamus and results in changes of pulse rate to optimize gas exchange from the lungs to the cells. In this investigation, students examine this feedback mechanism monitored by the brain and how the normal pulse rate is affected by a stressor, exercise.

The task assesses students' understanding of scientific inquiry including the following skills: observation, background research, scientific procedures (including investigation design, measurement techniques, and error analysis), data collection, data display, scientific questions, formulating a hypothesis, measurement skills.

This task is designed to take students approximately 45 minutes to gather data, report can be assigned.

Overall Task Content Area:

Life Science

Specific Knowledge Areas:

Regulation and behavior

  Homeostasis

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data
• formulating conclusions from investigational data

National Science Education Standards:

12 A SI 1: Abilities necessary to do scientific inquiry: Grades 9-12

1.2 Design and conduct scientific investigations. Designing and conducting a scientific investigation requires introduction to the major concepts in the area being investigated, proper equipment, safety precautions, assistance with methodological problems, recommendations for use of technologies, clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other than the actual investigation. The investigation may also require student clarification of the question, method, controls, and variables; student organization and display of data; student revision of methods and explanations; and a public presentation of the results with a critical response from peers. Regardless of the scientific investigation performed, students must use evidence, apply logic, and construct an argument for their proposed explanations.

1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.

8 C LS 3: Regulation and behavior: Grades 5-8

3.2 Regulation of an organism’s internal environment involves sensing the internal environment and changing physiologic activities to keep conditions within the range required to survive.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

National Council of Teachers of Mathematics:

AL1: Understand patterns, relations and functions:
Grades 9-12 n. interpret representations of functions of two variables

AL4: Analyze change in various contexts:
Grades 9-12 f. approximate and interpret rates of change form graphical and numerical data

DAP1: Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them:
Grades 9-12 l. understand the meaning of measurement data and categorical data, of univariate and bivariate data, and of the term variable
Grades 9-12 m. understand histograms, parallel box plots, and scatter plots and use them to display data

DAP2: Select and use appropriate statistical methods to analyze data :
Grades 9-12 h. for bivariate measurement data, be able to display a scatter plot, describe its shape, and determine regression coefficients, regression equations, and correlation coefficients using technological tools

PS2: Solve problems that arise in mathematics and in other contexts:
Grades 9-12

CNX3: Recognize and apply mathematics in contexts outside of mathematics:
Grades 9-12

General Instructions to the Teacher:

This task is designed to take students approximately 45 minutes to gather data, report can be assigned. .

Students should be ready to work as soon as periods begin. A central supply area, if needed, should be easily accessible. All supplies should be clearly labeled.

Materials for " Cardiovascular Homeostasis":

The student will need:

• Exercise equipment or space to exercise
• Timer

Advance Preparation:

• Students should not be allowed to frame questions that are already known (no common knowledge questions).
• Encourage questions that lead to mathematical, graphical analysis of variables and data. Look for correlations and relationships.
• Teacher questions: How do stressors affect homeostasis in the cardiovascular system? How does cardiovascular exercise affect the pulse rate?

Safety:

• Be careful.
• Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.

Extensions/modifications:

• N/A