Grade 7
Science
Unit: 10
Lesson: 01
Suggested Duration: 5 days
Homeostasis
Lesson Synopsis:
In this lesson, students will investigate and describe a variety of responses that plants and animals have to both internal
and external stimuli in order to maintain balance in internal conditions.
TEKS:
7.13
7.13A
7.13B
Organisms and environment. The student knows that a living organism must be able to maintain balance in stable
internal conditions in response to external and internal stimuli. The student is expected to:
Investigate how organisms respond to external stimuli found in the environment such as phototropism and fight or
flight.
Describe and relate responses in organisms that may result from internal stimuli such as wilting in plants and fever
or vomiting in animals that allow them to maintain balance.
Scientific Process TEKS:
7.1
7.1B
7.2
7.2A
7.2C
7.2D
7.3
7.3D
7.4
7.4A
Scientific investigation and reasoning. The student, for at least 40% of instructional time, conducts laboratory and
field investigations following safety procedures and environmentally appropriate and ethical practices. The student
is expected to:
Practice appropriate use and conservation of resources, including disposal, reuse, or recycling of materials.
Scientific investigation and reasoning. The student uses scientific inquiry methods during laboratory and field
investigations. The student is expected to:
Plan and implement comparative and descriptive investigations by making observations, asking well-defined
questions, and using appropriate equipment and technology.
Collect and record data using the International System of Units (SI) and qualitative means such as labeled drawings,
writing, and graphic organizers.
Construct tables and graphs, using repeated trials and means, to organize data and identify patterns.
Scientific investigation and reasoning. The student uses critical thinking, scientific reasoning, and problem solving
to make informed decisions and knows the contributions of relevant scientists. The student is expected to:
Identify advantages and limitations of models such as size, scale, properties, and materials.
Scientific investigation and reasoning. The student knows how to use a variety of tools and safety equipment to
conduct science inquiry. The student is expected to:
Use appropriate tools to collect, record, and analyze information, including life science models, hand lens,
stereoscopes, microscopes, beakers, Petri dishes, microscope slides, graduated cylinders, test tubes, meter sticks,
metric rulers, metric tape measures, timing devices, hot plates, balances, thermometers, calculators, water test kits,
computers, temperature and pH probes, collecting nets, insect traps, globes, digital cameras, journals/notebooks,
and other equipment as needed to teach the curriculum.
GETTING READY FOR INSTRUCTION
Performance Indicator(s):
•
Complete a laboratory report for a descriptive investigation in which an organism’s responses to stimuli are
observed. Include a description of the organism’s response to stimuli in the discussion section. (7.2A; 7.13A,
7.13B)
5C, 5F
Key Understandings and Guiding Questions:
•
Organisms respond to both external and internal stimuli.
— What are examples of external stimuli?
— What are examples of internal stimuli?
— How do organisms respond to internal or external stimuli?
— Why do organisms respond to internal or external stimuli?
— How do responses to stimuli help to maintain balance in organisms?
©2012, TESCCC
06/14/13
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Grade 7
Science
Unit: 09 Lesson: 01
Vocabulary of Instruction:
•
•
•
•
homeostasis
stimulus
internal stimulus
response
•
•
•
external stimulus
fight or flight
phototropism
• geotropism
• feedback mechanism
• stable/stability
Materials:
Refer to Notes for Teacher section for materials.
Attachments:
•
•
•
•
•
•
Handout: Monitoring Blood Sugar Levels (1 per student)
Teacher Resource: Monitoring Blood Sugar Levels KEY
Handout: Animal Responses (see Advance Preparation, 1 set per group)
Handout: Pill Bug Responses Laboratory Investigation (1 per group)
Teacher Resource: PowerPoint: Homeostasis Review
Teacher Resource: Performance Indicator Instructions KEY (1 for projection)
Advance Preparation:
1.
2.
3.
4.
Prior to Day 1: Secure access to student computers/Internet for diabetes research.
Prior to Day 2: Print, laminate, cut apart, and bag the Handout: Animal Responses (1 set per group).
Prior to Day 3: Locate a suitable area to observe transpiration in plants.
Prior to Day 4:
• Collect enough pill bugs for each lab group to have 10 with which to work. Pill bugs can usually be found
under boards or rocks in yards. Water the area well a few days before collecting the bugs. This should attract
pill bugs into the area. Pre-cut 10”x12” cardboard sections (1 per group). Pill bugs may also be ordered from a
scientific supply company.
5. Prior to Day 5: Locate and print the Lab Report. (A possible laboratory report format was included in Creating the
Science Notebook: A Tool for Evaluating Student Work, located in the Instructional Resources section.
6. Prepare attachment(s) as necessary.
Background Information:
Organisms are living systems that maintain a steady state with their environment. Their balance may be disrupted by
stimuli. Animals and plants respond to internal and external stimuli in their environment in order to maintain internal
balance. Animals respond to changes in the outside temperature and internal temperature by shivering or sweating. The
pupil of the eye responds to the amount of light available by contracting or dilating. Animals also respond to internal
stimuli. If a bacteria or virus enters the body, the immune system triggers a fever or vomiting response to deal with the
threat. Plants are also able to respond to stimuli. They exhibit positive geotropism by having their roots grow toward the
center of the Earth. Negative geotropism is evidenced by stems and leaves growing away from the Earth. Plants also
respond to external stimuli through phototropism (bending toward the light). Organisms return to a balanced state through
processes known as feedback mechanisms.
Prior to this lesson, students have had limited exposure to the idea that organisms respond to external or internal stimuli.
During this lesson, students should understand that a system can include processes, as well as parts. Thinking about
systems means identifying how every part relates to others. Output from one part of a system (which can include material,
energy, or information) can become input to other parts. Such feedback can serve to control what goes on in the system
as a whole. Any system is usually connected to other systems, both internally and externally, and still interacts with its
surrounding environment. When studying a system, it is important to keep track of what enters or leaves the system.
In previous lessons, students studied the human body systems and the adaptations of internal structures of organisms. In
this lesson, students will focus on how living organisms must be able to maintain balance in stable internal conditions
through responses to external and internal stimuli.
STAAR Notes:
Although not identified as a Supporting Standard, Student Expectation 7.13AB builds content in the area of describing,
comparing and contrasting internal and external stimuli. The concepts in this unit form the foundation for concepts tested
in Reporting Category 4: Biological Processes and Systems of the STAAR Biology Assessment.
©2012, TESCCC
06/14/13
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Grade 7
Science
Unit: 09 Lesson: 01
GETTING READY FOR INSTRUCTION SUPPLEMENTAL PLANNING DOCUMENT
Instructors are encouraged to supplement and substitute resources, materials, and activities to differentiate instruction to address the needs of learners.
The Exemplar Lessons are one approach to teaching and reaching the Performance Indicators and Specificity in the Instructional Focus
Document for this unit. Instructors are encouraged to create original lessons using the Content Creator in the Tools Tab located at the top of the page.
All originally authored lessons can be saved in the “My CSCOPE” Tab within the “My Content” area.
INSTRUCTIONAL PROCEDURES
©2012, TESCCC
06/14/13
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Instructional Procedures
Notes for Teacher
ENGAGE/EXPLORE/EXPLAIN – Insulin Regulation
NOTE: 1 Day = 50 minutes
Suggested Day 1
1. Say:
• We recently learned about the systems of the human body.
• Which system is responsible for chemical regulation? (Endocrine)
• What are some hormones that the endocrine system uses to
regulate the body? (Testosterone, estrogen, human growth hormone,
insulin)
• Today, we are going to look at how the body regulates the
amount of sugar in the blood using a simulation activity.
Materials:
• paper clips (small, 1 per group)
• graph paper (1 sheet per student)
• pencil (sharpened, 1 per group)
2. Divide the class into groups of 2–4.
3. Allow students about 10 minutes of time to research information (see
Advance Preparation) about the effects of diabetes on the body and steps
that may be taken to maintain healthy blood sugar levels. You may wish to
use the American Diabetes Association website at the following URL:
http://www.diabetes.org/diabetes-basics/ in order to filter the amount of
time students will need to retrieve the information.
4. Ask students to record information from the research in their science
notebooks.
5. Facilitate a class discussion about the information that the students
researched, including the importance of keeping blood sugar levels in a
healthy range (see Instructional Notes).
6. Distribute the Handout: Monitoring Blood Sugar Levels, and instruct
students to complete it with their groups. (Each group only needs one
spinner.) Point out that the activity is using the spinner as a model, and
discuss the advantages and limitations.
7. As students work on the activity, they will need to create a graph in their
notebooks. Point out the types of responses the body may have to control
the blood sugar levels. (See the Teacher Resource: Monitoring Blood
Sugar Levels KEY.)
Grade 7
Science
Unit: 09 Lesson: 01
Attachments:
• Handout: Monitoring Blood Sugar
Levels (1 per student)
• Teacher Resource: Monitoring
Blood Sugar Levels KEY
Instructional Notes:
Be sensitive to students who either have
diabetes or a family member with the
illness. Respect student needs for
privacy in sharing personal medical
information.
Instruct students on how to use the
spinners. They need to hold one end of
a paper clip in the center of the spinner
card with the point of a pencil. With their
free hand, they need to flick the other
end.
Optional: You may wish to modify the
Handout: Monitoring Blood Sugar
Levels and prepare a class set of
spinners in advance.
You may wish to lower the number of
spins required based on time.
8. In order to create a graph, either use paper and a pencil, an Excel
spreadsheet, or the website Create a Graph at the following URL:
http://nces.ed.gov/nceskids/createagraph/.
9. At the end of class, discuss the importance of how feedback mechanisms
allow the body to maintain a stable blood sugar in the body (see
Instructional Notes).
10. Ask:
• How will a person know if he/she has high or low blood sugar?
They will exhibit symptoms.
• What is the body’s response to unstable blood sugar? Symptoms
will be presented.
• How can the body stabilize the blood sugar? Insulin or food
Science Notebooks:
Students record research information on
the effects of diabetes on the body and
create a graph of data collected.
Students define the term “feedback
mechanism”.
11. Instruct students to record the term “feedback mechanism” in their
notebooks and work with a partner to develop a working definition.
EXPLORE/EXPLAIN – Responses in Animals
1. Say:
• Yesterday, you completed an activity to illustrate how the body
maintains a stable blood sugar using insulin or food. Today, you
will continue to explore ways that animals maintain a stable
internal environment.
©2012,
TESCCC
2. Divide
the
class into groups of 3–4.
06/14/13
3. Distribute a set of cards from the Handout: Animal Responses (see
Suggested Day 2
Attachments:
• Handout: Animal Responses (see
Advance Preparation, 1 set per
group)
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Misconception:
• Students may think
Grade 7
Science
Unit: 09 Lesson: 01
©2012, TESCCC
06/14/13
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