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Erin M. Flynn
Homeostasis Unit Matrix
10th Grade Biology
March 3, 2016
Subject area description:
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The topic of this unit of instruction is homeostasis; it will be the first unit of
the school year. The purpose behind starting the year with a unit such as this is that
at the high school where I will be teaching Biology (Inglemoor High School in
Kenmore), they have traditionally began the year with a unit on “Basics of Biology:
Cells,” and I decided that this is not an ideal way to begin a biology class. It is more
appropriate to begin the year with a unit that studies a phenomenon like homeostasis,
which can be examined in a variety of ways that can be more readily seen as related
to students’ lives and thus a more engaging way to begin the course and set the tone
for the remainder of the year. It is difficult to begin the school year with the
students studying the structure and functions of cells, which are microscopic, basic
units of life. Students who are unfamiliar with biology may not appreciate the
importance of cells if they do not have any context in which they can understand that
cells are essential for all living organisms. I will approach homeostasis from two
levels: the organismal and the cellular. This unit will directly lead into a unit on the
structure and function of cells, which was originally planned to come first. The
students who will be learning this material will be 10 th graders, both “honors” and
“non-honors” students, native and non-native (ELL) students, and students with IEP or
504 plans, all mixed in the room (the school is generally untracked with the exception
of the IB program, which I will not be teaching). Hopefully the students will come
into my classroom with some Life Science experience from Junior High, as well as
some background in the scientific method; but I will be prepared to back up and
support the students’ learning if I ever hit a roadblock in students understanding due
to lack of background. Since it is the beginning of the school year, I will assume that
students come to class with a rusty mind that I will need to lubricate to get working
properly (after the long summer months!). I will do this through engaging students in
a variety of hands-on activities and introducing scientific inquiry (to norm this type of
“doing science” early on). One thing to keep in mind is that Inglemoor is on a semiblock schedule; each class period meets Monday and Friday for 53 min., and meets
two of the three “middle days” (Tuesday, Wednesday, Thursday) for 75 min.
Essential questions and content and skills necessary to answer the EQ’s:
1. Why don’t we (as healthy individuals) overheat and get very sick when the
temperature in Kenmore reaches 110°F during a 6-day heat wave in mid-August
(assume we do not have air conditioning)?
In order to answer this question, students must understand how the human
body responds to changes in ambient temperature. They must have a conceptual
understanding of how sweating is involved in maintaining homeostasis in the body.
They must also understand that the difference between the average resting
temperature of a human (98.6°F) and the temperature of the environment must be
small enough for the body to compensate for the difference without resorting to the
use of external “equipment” (i.e. a cool swimming pool in the heat, a down jacket in
the cold) to help regulate core body temperature or the chance of survival is slim.
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2. How does your body physically respond to strenuous exercise? In other words,
what exactly is happening inside your body when you are running around while
participating in your favorite sport?
This question allows the student to expand upon his/her knowledge and
understanding from question #1, so understanding thermoregulation by sweating is
essential to answering this question. It will also be important to understand that
there will be an imbalance in osmoregulation of the cells in the body if water is not
consumed to replace what evaporates through sweating. The student will also delve
into the digestive and circulatory systems and understand their cooperative role in
bringing available nutrients to the muscles, whose nutrient stores have become
depleted as a result of exercise. Students must also able to understand the interplay
between the respiratory system and the circulatory system for the continual delivery
of oxygen to the cells (utilized during cellular respiration, increased in muscle cells
during exercise).
Learning goals and objectives:
1. Students will analyze systems, including inputs and outputs. (EALR 1.2.1)
1.1 Students will understand that homeostasis is a state of balance, where the
system (be it an organism, tissue, organ, or cell) responds to changes in the
environment (internal or external) by making adjustments within the
system in order to regain that balance.
1.2 Students will know that the human body responds to physical exercise by
increasing heart rate, and that this rate will return to “normal” following
an appropriate rest period.
1.3 Students will understand that temperature regulation in an endotherm is an
example of homeostatic balance, and be able to explain this phenomenon
through this lens.
2. Students will explain how organisms can sustain life by obtaining, transporting,
transforming, releasing, and eliminating matter and energy. (EALR 1.3.7)
2.1 Students will apply the principle of homeostasis to the human body’s
responses to strenuous exercise, including the transport of oxygen and
nutrients to the working muscles of the body.
2.2 Students will demonstrate understanding of diffusion across a selectively
permeable membrane.
2.3 Students will demonstrate understanding of the phenomenon of osmosis.
2.4 Students will know the difference between osmosis in a plant and animal
cell.
3. Students will design, conduct, and evaluate systematic and complex scientific
investigations, using appropriate technology, multiple measures, and safe
approaches. (EALR 2.1.2)
3.1 Students will understand how to create scientifically valid hypotheses.
3.2 Students will understand how to create and revise a scientific model based
on their hypothesis and data analysis.
3.3 Students will understand that conclusions must be based solely on the data
collected during experimentation; any claims outside of this data are
unsubstantiated.
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4. Students will learn to become more scientifically literate citizens and apply their
knowledge to situations occurring in every day life.
4.1 Students will know that equilibrium is a ubiquitous concept that is
important to the smooth workings of many systems in “the real world.”
4.2 Students will be able to explain osmosis by referring to examples in their
everyday life.
5. Students will display skills important to “doing science” in an authentic setting.
5.1 Students will learn to work well with their peers through group work.
5.2 Students will learn to safely handle equipment and chemicals in the lab.
5.3 Students will express ideas through oral and written expression (EALR
2.1.5).
5.4 Students will defend their scientific conclusions or arguments (EALR 2.1.5).
Unit matrix
Day 1: Building a knowledge base for “equilibrium” (53 min.)
1. What students are doing
Students will watch a demonstration by the teacher
of a simple see-saw balance in equilibrium, and
then in an imbalanced state.
Students will
explicitly describe (through class discussion) what
caused the imbalance in this system, and suggest
ways to rebalance the see-saw. In groups of 4,
students will brainstorm ideas about situations in
life where equilibrium is important (e.g. a bank, a
supermarket, etc.). Students will then write a
paragraph summary of their ideas and share with
the class. Remind students at the end of the period
that they must be prepared to do some exercise in
tomorrow’s class (dress appropriately).
2. Objectives
4.1 Students will know that equilibrium is a
ubiquitous concept that is important to the smooth
workings of many systems in “the real world.”
5.1 Students will learn to work well with their
peers through group work.
3. Reasons for content and This is the first instructional unit of the school year.
instructional strategy
I am working with the assumption that the students
will not have much detailed knowledge of biological
principles such as homeostasis, so my intention is to
scaffold their understanding in small steps. I begin
by using a simple example of a balance (the
“hook”), which most students will likely be able to
explain. Then, I will get the students to think in
more depth about examples of equilibrium that
they bring to the classroom (eliciting students’
ideas); I can draw parallel information from these
examples in future lessons when I introduce the
concept of biological equilibrium, or homeostasis. I
4. Evidence of understanding
5. Resources
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also want to make working in groups a norm in my
classroom, so I begin this on day one. It is
important for students to learn to gather ideas from
each other and come to a group understanding or
explanation of a phenomenon. This is a skill that
will help them in life, in science or wherever their
future takes them.
Students will present their ideas to the class. This
will make it explicit to me whether or not they
understand the idea of equilibrium. Students will
fill out a self-evaluation on their group work skills
for the day which will be kept in their portfolio.
Simple balance (can be made from a ruler balanced
upon a triangular block); wooden blocks of various
sizes (for demo). Manila folders for each student to
begin his/her portfolio. Handout of criteria for
group work (one per student).
Day 2: What happens during exercise? (75 min.)
1. What students are doing
Students will participate in small group discussions
(the same groups of 4 from day 1) about the
following question: “How does the human body
maintain its weight? Explain how one could go
about losing weight, and how one could gain weight
(and, more importantly, why this occurs … thinking
back to our group work yesterday),” (eliciting
student ideas).
Students will do a small inquiry activity that
introduces the concept of homeostasis in our own
bodies. As part of a class discussion, students will
answer the question, “What changes do you notice
in your body after you do a shuttle run in P.E.
class?” (Phase I- building a knowledge base). In
pairs, students will make a prediction about what
will happen to their heart rate after exercising, and
what will happen over time while they rest
following activity. They will diagram a simple
model that represents their hypothesis (Phase IIhypotheses & initial models). Then students will
make a data table in which they will collect data
for their heart rate at rest, after 10 jumping jacks,
after 20 jumping jacks, after 30 jumping jacks, and
after 3 – 30 sec. intervals of rest, or until their
heart rate returns to its original resting rate. Each
student will collect data about his/her own heart
rate. In the first trial, one student measures and
collects data and the other exercises, then they
switch roles for the second trial (Phase IIIconducting the investigation).
Students will
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consider their data sets and determine whether
their hypothesis was accurate (Phase IV- analyzing
data), and will make any necessary revisions to
their model (Phase V- reconsidering the model).
2. Objectives
1.2 Students will know that the human body
responds to physical exercise by increasing heart
rate, and that this rate will return to “normal”
following an appropriate rest period.
3.2 Students will understand how to create and
revise a scientific model based on their hypothesis
and data analysis.
3. Reasons for content and This day begins with a brief discussion about the
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human body and how equilibrium in weight is
maintained or disrupted. This is an opportunity to
get the students to draw from materials learned
during the previous lesson and situate their next
activity.
Then the students participate in a
structured inquiry activity. The activity is designed
for students who may not have very much exposure
to scientific inquiry and need a highly structured
protocol with areas where they can practice some
of
the
skills
necessary
for
scientific
experimentation such as building models, creating
hypotheses, carrying out a protocol, and analyzing
data. The purpose of using heart rate response to
exercise for this activity is to get students to think
about the human body as a system where
homeostasis is extremely important. The major
purpose for this day is to practice science skills and
regain comfort and confidence in “scientific lingo”
while discovering content. Because of the nature
of the experiment, this is a good activity to use to
assess student’s experience with scientific inquiry; I
will be able to observe students’ comfort levels
with inquiry skills.
4. Evidence of understanding
I will circulate throughout the room while students
are doing their data collections and make sure that
they are on track, and answer any questions. This
doubles as an opportunity to make informal
observational assessments for each pair of students.
After the students have revised their models, I can
make another informal assessment based on the
students’ understanding of how to create and revise
models, comparing to what I observed the initial
model to be earlier during rounds.
5. Resources
Stopwatches.
Day 3: Why does heart rate change after exercise? (75 min.)
1. What students are doing
Students will continue with their information
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gathered during the previous day’s activity. If any
portion of the activity was not completed in the
last class period, there will be time at the
beginning of this class to finish up. Each pair will
draw their revised model on the board, and the
class will hold a discussion about the similarities
and differences of the classes’ results. When this
has been completed, students will get back into
their original group of 4 (from day 1) and discuss
the results of their experiments and brainstorm
reasons why they think that the heart rate may
have changed the way it did based on their models.
Each group will write their “best” explanation on
an overhead sheet that will be displayed for the
class. The class will then discuss these ideas and
come to a consensus as to which are the most
salient. The class will then listen to a mini-lesson
on the cardiovascular system and its role in
transporting oxygen and nutrients to working
muscles, and will take notes in their notebooks.
2. Objectives
1.1 Students will understand that homeostasis is a
state of balance, where the system (be it an
organism, tissue, organ, or cell) responds to
changes in the environment (internal or external)
by making adjustments within the system in order
to regain that balance.
3.2 Students will understand how to create and
revise a scientific model based on their hypothesis
and data analysis.
3. Reasons for content and The students will present their model to the class
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by drawing it on the board. I will lead a class
discussion that will involve the students critiquing
the presented models, comparing and contrasting
the models, and compiling the class’ ideas into one
class model. The purpose of this strategy is to give
students the experience of sharing their ideas with
their peers and to get them to defend their
scientific thinking. Having the students regroup in
their small discussion groups to draw scientific
conclusions based on the class model is important in
bridging the gap between the activity, discovering
what happened to the heart rate after exercise;
and the scientific explanation for why this
phenomenon occurs. It is an important sense
making process, and it directly leads into a
“teachable moment” about the cardiovascular
system’s role in delivering oxygen and nutrients to
working muscles. This information is delivered to
the students when they have reached an impasse in
4. Evidence of understanding
5. Resources
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their abilities to explain the phenomenon they
observed.
This also gives the teacher the
opportunity to circle back and directly explain this
in terms of homeostasis, relating back to the first
activities the students did, discussing equilibrium.
The purpose of having the students evaluate all of
the models and combine them into one class model
(Phase V- assessment) is for the teacher to have a
way of assessing each group’s work and to assess
whether or not the class understands how to build a
simple model.
For homework, students will do a free write
explaining why they think humans breathe deeper
and at a faster rate during exercise. This gives the
students an opportunity to take what they have
learned about homeostasis in the human body with
reference to heart rate and apply it to a new
situation. I will read through the responses to get a
sense for how many students have a true
understanding of the concept of homeostasis in
these situations.
Both the free write and the class model will be
added to each student’s portfolio.
Overhead projector, overhead sheets, overhead
pens, notes for mini-lesson on the cardiovascular
system, an overhead of the cardiovascular system
for reference.
Day 4: Wrap up exercise activity; Chicken egg osmosis! (53 min.)
1. What students are doing
In their small groups of 4, students will create a
diagram depicting the human body and the changes
that must be made when homeostasis is disrupted
(by exercise). Students must explain what the
output of the system is and what the input must be
to regain equilibrium. Students will also explain
why the heart rate returns to normal rate after
sufficient rest (30 min.).
Students will format their lab notebook with a table
of contents on the first page. Students will work in
pairs for this lab. Students will begin their lab
notebook entry for the “Chicken Egg Lab” (format
cover page and make a data table). Each pair of
students will measure initial data for their egg:
circumference of egg and mass of egg. Students
will put their egg in a beaker of vinegar and record
observations (23 min.).
2. Objectives
2.1 Students will apply the principle of homeostasis
to the human body’s responses to strenuous
exercise, including the transport of oxygen and
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nutrients to the working muscles of the body.
5.2 Students will learn to safely handle equipment
and chemicals in the lab.
3. Reasons for content and The students apply their new knowledge of
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homeostasis (from the previous day’s lesson) to
their model by diagramming what changes occur in
the body relating to homeostatic balance when it is
disrupted during exercise in a poster format. This
gives the students the opportunity to draw
meaningful scientific conclusions from their data
and their model, and brings some closure to the
activity while leading nicely into the next activity
on osmosis. I am beginning the inquiry activity at
this time because it is going to be a fairly time
consuming activity (short periods of time over
several days); and the first step needs to go over
the weekend.
4. Evidence of understanding
I will collect the group posters, and assess the
students understanding of homeostasis through
their representations on the poster. I will take
digital images of the student’s posters that can be
filed in the students portfolios as evidence of their
understanding.
I will observe the students during their laboratory
exercise to be sure that they understand how to
safely perform the skills necessary in making the
preliminary measurements. I will also carefully
monitor the students for the utilization of their
safety goggles when they are working with
chemicals in this lab (vinegar).
5. Resources
Poster board, markers, raw chicken eggs, strong
vinegar, plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, handout for
“Chicken egg lab.”
Day 5: How does our body survive environmental temperature changes? (53 min.)
1. What students are doing
Students will measure the circumference and mass
of their egg and record any observations. They will
replace the vinegar with high concentration salt
water, observe the egg for a few minutes, and then
record any new observations.
All data and
observations will be recorded in the data table in
their lab notebooks. Safety goggles will be worn at
all times during this activity.
In small groups (3 or 4), students will discuss their
ideas about the following prompt: “Why don’t we
(as healthy individuals) overheat and get very sick
when the temperature in Kenmore reaches 110°F
during a 6-day heat wave in mid-August (assume we
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do not have air conditioning)?” They will write
their brainstorming ideas down on a piece of paper
that they will bring to the next class.
2. Objectives
1.3 Students will understand that temperature
regulation in mammals is an example of
homeostatic balance, and be able to explain this
phenomenon through this lens.
5.1 Students will learn to work well with their
peers through group work.
3. Reasons for content and The laboratory exercise will be ongoing throughout
instructional strategy
the week, so the beginning of the class today is
dedicated to part of this activity.
The students will participate in more group
discussions, utilizing their previous knowledge from
class (and from outside of class) to discuss
homeostasis in terms of temperature regulation.
This is another chance for eliciting student ideas.
4. Evidence of understanding
I will listen to student discourse during small group
discussion to see what their ideas are and to make
sure that they are making the proper connections to
prior knowledge about homeostasis.
Students will fill out a self evaluation on their group
work skills for the day which will be kept in their
portfolio.
5. Resources
Plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, high
concentration salt water.
Day 6: Why do I have Goosebumps? Brrr… (75 min.)
1. What students are doing
Students will measure the circumference and mass
of their egg and record any observations. They will
replace the colored water with fresh water,
observe the egg for a few minutes, and then record
any new observations. All data and observations
will be recorded in the data table in their lab
notebooks. Safety goggles will be worn at all times
during this activity.
As a continuation of yesterday’s group discussion,
the small groups will reconvene and continue their
discussions. As a group, students will come up with
a model of what they believe happens in the body
when the environmental temperature is both
warmer and colder than the average human’s core
body temperature that aid in survival during these
changes.
They will explain this in terms of
homeostatic balance. Each student must have a
copy of this initial model.
Students will then listen to a mini-lesson on
thermoregulation. Students will take notes in their
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notebooks.
1.3 Students will understand that temperature
regulation in an endotherm is an example of
homeostatic balance, and be able to explain this
phenomenon through this lens.
3.2 Students will understand how to create and
revise a scientific model based on their hypothesis
and data analysis.
3. Reasons for content and The laboratory exercise will be ongoing throughout
instructional strategy
the week, so the beginning of the class today is
dedicated to part of this activity.
Students then have another opportunity to create a
model of how they imagine thermoregulation to
work in mammals, utilizing their understanding of
homeostasis to explain this phenomenon. It is
another opportunity for students to understand this
principle of balance in a new situation.
4. Evidence of understanding
For homework, the students will each revise their
original model based on the information they
received in class. Their initial model and their
revised model will be fastened together and added
into their portfolio. I will be able to assess their
process of designing and revising a model as well as
their conceptual understanding of thermoregulation
from this activity.
5. Resources
Plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, fresh water.
2. Objectives
Day 7: Introducing diffusion (75 min.)
1. What students are doing
Students will measure the circumference and mass
of their egg and record any observations. They will
replace the high concentration salt water with corn
syrup, observe the egg for a few minutes, and then
record any new observations.
All data and
observations will be recorded in the data table in
their lab notebooks. Safety goggles will be worn at
all times during this activity.
Students will perform a laboratory experiment:
Diffusion across a selectively permeable membrane.
In this activity, students will put two different
molecules in dialysis tubing, Riboflavin and Dextran
(a complex compound sugar that is labeled with an
attached dye). Students will design a controlled
experiment in which they can determine which
molecule will be able to cross the membrane. The
experiment will go on overnight. Safety goggles
will be worn at all times during this activity.
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2. Objectives
2.2 Students will demonstrate understanding of
diffusion across a selectively permeable membrane.
3.1 Students will understand how to create
scientifically valid hypotheses.
3. Reasons for content and In order to have a better understanding of what is
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going on in the chicken egg lab; students will do a
small experiment in which they observe diffusion
across a selectively permeable membrane. I do not
intend to make obvious the connections between
the two labs, that should be made by the students
in answering questions in the future days planned
for the chicken egg lab.
This mini lab is structured in such a way that the
students can have plenty of support in how to
organize their thoughts in designing their
experiment (there are specific steps that they need
to follow before “doing the experiment”). This will
help scaffold the students understanding of the
scientific process.
All steps will be written in their lab notebooks
immediately following the chicken egg lab, and
formatted in the same way.
4. Evidence of understanding
The first objective (2.2) really will not be assessed
on this day since it is a two day experiment, but it
will be introduced and explored.
I will check student’s hypotheses before they can
continue and begin their experiment; this way I can
assess for understanding of how to create a valid,
testable hypothesis.
5. Resources
Plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, corn syrup,
dialysis tubing, Riboflavin, Dextran (dye-labeled),
stir bars, stir plates, plastic transfer pipettes.
Day 8: Continuing diffusion … (53 min.)
1. What students are doing
Students will measure the circumference and mass
of their egg and record any observations. They will
replace the old corn syrup with fresh corn syrup,
observe the egg for a few minutes, and then record
any new observations. All data and observations
will be recorded in the data table in their lab
notebooks. Safety goggles will be worn at all times
during this activity.
Students will then observe and record information
about any changes to their dialysis tubing
experiment. Safety goggles will be worn at all
times during this activity. Then they will write a
conclusion for their experiment, addressing
whether or not their hypothesis was correct and
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why.
2.2 Students will demonstrate understanding of
diffusion across a selectively permeable membrane.
3.3 Students will understand that conclusions must
be based solely on the data collected during
experimentation; any claims outside of this data
are unsubstantiated.
3. Reasons for content and Students will concentrate on drawing feasible,
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substantiated conclusions based on the data they
have collected during their diffusion activity. This
is going to be good practice for the final phase of
the chicken egg lab that will be done in the next
class period.
4. Evidence of understanding
Based on the conclusions written in the students lab
write up, I can assess for understanding of the
principle of diffusion. I will also be able to assess
their understanding of objective 3.3 based on this
conclusion, if explanations appear that are outside
of the support of the evidence, then I will know
that I need to reiterate the importance of this
objective.
5. Resources
Plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, corn syrup.
2. Objectives
Day 9: My own experiment! (53 min.)
1. What students are doing
Students will measure the circumference and mass
of their egg and record any observations. Students
will deliberate over the findings in their chicken
egg lab so far. They will answer the following
question in their lab notebook: “In what liquids did
the egg’s size increase?
Decrease?
What
explanations might you have to explain this
phenomenon?” Students will then design their own
experiment.
The students will choose from a
variety of liquids provided by the teacher, which
they will add to their chicken egg and observe the
changes. First, they must create a hypothesis for
what they think will happen to the egg, and write
an explanation in their notebook as to why it will
happen (scientific reasoning based on previous
evidence). Then, they may add the chosen liquid to
their egg, and record any observations. All data
and observations will be recorded in the data table
in their lab notebooks. Safety goggles will be worn
at all times during this activity.
2. Objectives
2.3 Students will demonstrate understanding of the
phenomenon of osmosis.
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3.1 Students will understand how to create
scientifically valid hypotheses.
3. Reasons for content and By this point, students have had an opportunity to
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observe osmosis in their chicken egg, and it is
reasonable that they might be able to come up with
an explanation for their observations. Based on
their evidence, they are at a point where they can
design their own experiment and test their
hypothesis regarding a new liquid in their egg
model and what might occur. The students have
had some experience in designing their own
experiment (in the diffusion lab), so it is a good
time to build on that skill.
4. Evidence of understanding
I will check students’ hypotheses to make sure that
they are valid and testable before they try to do
their experiment.
I will listen to student dialogue to get an idea of
the class’ understanding of osmosis.
5. Resources
Plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, a variety of
liquids (such as vegetable oil, soy sauce, water with
food coloring, etc.).
Day 10: Wrap-up “Chicken egg lab” (75 min.)
1. What students are doing
Students will measure the circumference and mass
of their egg and record any observations. All data
and observations will be recorded in the data table
in their lab notebooks. Safety goggles will be worn
at all times during this activity. Once all data has
been collected, students will create a graph of
their data (egg’s circumference vs. mass) to paste
into their lab notebooks. Then they will answer the
following questions in a conclusions section:
1.) “Was your hypothesis correct? Describe why
your experiment either proved or disproved your
hypothesis. Use interpretations of your graph as
evidence to support your argument.”
2.) “Based on your knowledge of the movement of
molecules across the chicken membrane, can you
explain what might happen to an animal cell that is
placed in a high concentration of salt water? Relate
your explanation to your findings. Why might this
be an important process for cell survival?”
2. Objectives
2.3 Students will demonstrate understanding of the
phenomenon of osmosis.
3.3 Students will understand that conclusions must
be based solely on the data collected during
experimentation; any claims outside of this data
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are unsubstantiated.
3. Reasons for content and This lesson is gives an opportunity for students to
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bring everything together and have a “sensemaking” session with their lab partner.
The
questions have been designed to get the kids
thinking about how to apply this knowledge to a
new situation (relate the egg to an animal cell).
This is important because the unit following this
homeostasis unit will be on cell structure and
function, so this is a good segue into that unit. I
again reiterate the importance of drawing
conclusions solely based on evidence collected
during the activity. This is essential to good
science and I personally find it to be an important
aspect of doing laboratory science that I would like
to stress to the students regularly.
4. Evidence of understanding
When the lab write-ups are complete, I will collect
the lab notebooks and grade both the diffusion lab
and the osmosis lab. I will be able to assess for
student understanding of both objectives for the
day.
5. Resources
Plastic beakers, string, rulers, Petri dishes,
electronic weigh scale, safety goggles, graphing
paper, colored pencils.
Day 11: What is osmosis? (75 min.)
1. What students are doing
Students will listen to a mini-lesson on the
phenomenon of osmosis in a cell. Students will do a
mini-activity to support their understanding of
osmosis. They will create a wet mount of a piece
of onion skin using distilled water, and observe it
under the microscope. Then they will replace the
water with a 10% NaCl solution and observe any
changes. Finally, they will wash out the salt by
adding several “irrigations” of distilled water and
observe any changes.
They should record all
observations in their lab notebooks, and come up
with a rule that explains their observations. Then
students will listen to another mini-lesson about the
differences between osmosis in a plant cell and in
an animal cell.
2. Objectives
2.4 Students will know the difference between
osmosis in a plant and animal cell.
4.2 Students will be able to explain osmosis by
referring to examples in their everyday life.
3. Reasons for content and This class period is a prime opportunity for some
instructional strategy
“just in time teaching” about osmosis in cells. We
have not had much of a chance to relate to cells up
to this point, so it is a good opportunity to get the
4. Evidence of understanding
5. Resources
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students thinking on this level. I chose a “guided
inquiry” activity for this lesson as well, to give the
students an opportunity to see osmosis occur in a
plant cell, and build from their understanding of
osmosis in the chicken egg.
For homework, the students will answer the
following questions:
1. “If a lawn is fertilized and it does not rain, the
grass often dies. Why?”
2. “Roads are sometimes salted to melt ice. What
does this salting do to the plants along the
roadside? Why?”
3. “(For extra credit) – The Paramecium, a single
celled protest (no cell wall), lives in pond water.
Water tends to enter the cell through osmosis.
What kind of structure would need to exist in the
cell in order to osmoregulate (control water
balance)?”
Onion, distilled water, 10% NaCl solution, paper
toweling, glass slides, cover slips, eyedroppers,
dissecting microscopes (Objective 10X), overhead
projector, overheads of plant and animal cells.
Day 12/13: Wrap-up of homeostasis! (53 min.)
1. What students are doing
Students will work on culminating product. In
pairs, students will answer the essential question
posed at the beginning of the unit, “How does your
body physically respond to strenuous exercise?”
They will describe (in detail) what is happening at
an organ/tissue level within the organism, and what
is happening at the cellular level. They will have
two days to work in class on this project, and will
have the weekend to do any work together outside
of class. The final product will be a poster.
Students should use the information they have
collected in their lab notebooks as well as in their
portfolios to aid in this task. They may also ask for
the teacher’s help in understanding more details
about the system that they have chosen.
2. Objectives
1.1 Students will understand that homeostasis is a
state of balance, where the system (be it an
organism, tissue, organ, or cell) responds to
changes in the environment (internal or external)
by making adjustments within the system in order
to regain that balance.
5.1 Students will learn to work well with their
peers through group work.
3. Reasons for content and This culminating project incorporates many
instructional strategy
important aspects of “doing science”: working with
4. Evidence of understanding
5. Resources
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peers, integrating conceptual understanding of
information gathered through experimentation,
creating a poster, defending your ideas about a
particular topic to your peers, and asking
thoughtful scientific questions. I integrated all of
these aspects of good science in an authentic task
so that students have experience early in the year
with assembling conceptual information in a
valuable way.
The posters will be graded on content
understanding.
Students will fill out a self
evaluation on their group work skills for the day
which will be kept in their portfolio.
Poster board, colored pencils, crayons, markers,
glue, scissors, paper.
Day 14: Presentations! (75 min.)
1. What students are doing
Students will present their posters. One of the pair
of students will stand by his/her poster to offer
explanation and answer any questions posed by the
visitors. The other of the pair will walk around and
visit other posters, and ask questions about their
work. After 30 minutes, they switch roles.
2. Objectives
5.3 Students will express ideas through oral and
written expression (EALR 2.1.5).
5.4 Students will defend their scientific conclusions
or arguments (EALR 2.1.5).
3. Reasons for content and I believe that this is a fantastic way to get kids to
instructional strategy
communicate with their peers about science. It
forces them to explain their thinking to other
students, to defend their conclusions based on
evaluation of data and understanding of the
concepts of the unit. It is good practice for them
to get ready for the unit exam.
4. Evidence of understanding
Students will fill out peer assessments which
include how well the presenter of the poster
answered questions, and I will go around the room
and ask clarifying questions of the presenters as
well. I will be able to assess how well the student
expresses him/herself orally, and how well they
understand the concepts of the unit by their
success in defending their arguments.
5. Resources
Tape, thumbtacks.
Unit ends with a culminating unit exam; traditional items; 75 min. class period.
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Erin M. Flynn
Homeostasis Unit: Pre-Planning
Products
10th Grade Biology
March 3, 2016
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Unit Pre-planning Products
1. Topic/Concept of Unit
EALRs relevant to topic:
1.2.1: Analyze systems, including inputs and outputs.
This will be covered in the discussions surrounding homeostasis and temperature
regulation in animals.
1.3.7: Explain how organisms can sustain life by obtaining, transporting, transforming,
releasing, and eliminating matter and energy.
This will be essential in the discovery of both homeostasis within an animal and at the
cellular level.
2.1.2: Design, conduct, and evaluate systematic and complex scientific investigations,
using appropriate technology, multiple measures, and safe approaches.
Students will perform guided discovery activity as a performance assessment for
osmosis in a chicken egg; activity will begin highly structured and will lead to the
eventual design of a small portion of the experiment by the students.
2.1.3: Formulate and revise scientific explanations and models using logic and
evidence; recognize and analyze alternative explanations and predictions.
As part of the osmosis activity, students will be asked to revisit hypotheses and either
support or refute based on data collected and observations made.
2.1.5: Research, interpret and defend scientific investigations, conclusions, or
arguments; use data, logic, and analytic thinking as investigative tools; express ideas
through oral, written, and mathematical expression.
Claims made by the students will need to be supported by evidence gathered during
experimentation. Formal lab write-ups will be done.
3.1.3: Compare, contrast, and critique divergent results from scientific investigations
based on scientific arguments and explanations.
Students will share a summary of their results with the class and be able to discuss
divergent results in a scientific manner (arguments based on evidence.
Where does this fall in the Atlas of Scientific Literacy?
The topic of homeostasis falls into the Atlas of Scientific Literacy under a couple of
different webs. The main (or most relevant) web for osmosis and diffusion falls under
“Cells: Cell Functions.” Within this map, there is a section that states, “Within cells,
many of the basic functions of organisms – such as extracting energy from food and
getting rid of waste – are carried out. The way in which cells function is similar in all
living organisms.” This can be directly related to regulation in the internal systems of
an animal.
2. Rationale Paragraph
The topic of the unit I will be preparing is homeostasis, which is an extremely
important topic in biology. Homeostasis falls into the Atlas of Scientific Literacy under
a couple of different webs. The main (or most relevant) web for osmosis and
diffusion falls under “Cells: Cell Functions.” Within this map, there is a section that
states, “Within cells, many of the basic functions of organisms – such as extracting
energy from food and getting rid of waste – are carried out. The way in which cells
function is similar in all living organisms.” This can be directly related to regulation
in the internal systems of an animal. Another reason that this topic is essential is that
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it is found in the Washington State EALRs, #1.3.7: “Explain how organisms can sustain
life by obtaining, transporting, transforming, releasing, and eliminating matter and
energy.” This is the crux of homeostasis within an organism and directly parallels the
Atlas findings (above). The homeostasis unit will be one of the first units of the
school year. I intend it to begin with the regulation of an animal’s internal
environment on a systems level, such as temperature regulation; and end with
cellular regulation such as osmoregulation, to lead into future lessons on cellular
structure and functions. I have been trying to find a way to begin the school year
with a relatively simple concept (balance and regulation) that can immediately
engage students by the sheer nature of the obvious necessity of balance in life. I
think that it would be easier to get kids to begin to understand some complex topics
in biology if I can give them a solid understanding of the importance of balance and
regulation in organisms and cells. From there, they could see the running theme in
the unit on ecosystems, more specifically in predator/prey relationships and
population ecology; in the conservation of energy, and many other big ideas in
science that directly relate to balance. The study of regulation in the internal
environment of an animal can lead to the study of regulation in cells, which can lead
to more detailed studies of cellular structures and their related functions, of the
similarities of organ systems among various organisms, etc. This unit is primarily a
way to get kids thinking about science, to give them a “lead-in” to other topics of
importance in the study of biology. Understanding homeostasis will allow for students
to understand the principle of balance that s/he witnesses in his/her everyday life.
For example, the studies of the checks and balances in the United States government
may be clearer after understanding the principles governing the maintenance of
balance on a biological level. The student will have a better grasp of how businesses
become successful, the flow of money, of personnel, of materials and products. S/he
will understand why it is important for our country to invest time and money into
generating a substitute for oil that is inexpensive and simple to create. These three
situations all relate to the general idea of balance, of a simple give and take
necessary to keep a system stable and functioning well.
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3. Concept Map of Topic (minimum 20 nodes) (see Powerpoint file)
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4. Critical Attributes
1. Homeostasis is achieved through a variety of mechanisms that auto-correct for
small differences in their internal and/or external environment(s).
2. The exchange of energy and materials with the environment is balanced by
homeostasis.
3. Single-celled organisms have regulatory systems in place that permit them to
survive extremely harsh osmotic environments.
4. An animal’s metabolism can change in response to a variety of stimuli, keeping
the animal stable (body mass, temperature, etc.).
5. The circulatory system of large animals (and blood in particular) is an
extremely important player in most homeostatic processes in the animal.
5. Description of Culminating Project or Product
The culminating product for this unit will be a poster project in which the
students describe in detail one of the many aspects of the essential question, “How
does your body physically respond to strenuous exercise?” Students will work in pairs
to produce a poster that provides examples and explanations of homeostasis at two
levels: in the whole organism, with respect to homeostatic balance regulated by an
organ/tissue system; and in a cell. Students must produce a graphic representation of
their examples for each of the levels of homeostasis involved in this poster summary.
They may draw pictures, use magazine clippings, download appropriate pictures from
the internet, etc. Under each diagram, there must be a typed “figure legend” pasted
below, explaining in detail what the student is depicting and how it represents
homeostasis at that level. The students may choose to describe what is happening in
a cell within the context of their organ/tissue example; or it could be an entirely
different unrelated example.
The descriptive text (for each of the examples) should include the following:
 What the imbalance is in the example and what caused it
 What adjustments must be made to return to a homeostatic balance
 Whether or not energy is needed to reset the system to a balance
 One must include the concept of osmosis/diffusion
 One must include a discussion of the influence of metabolism on this system
 The tissue/organ system example must be chosen from the following list
(students are expected to do more in depth research on their specific system
and explain it’s role in maintaining homeostasis in an organism):
o Circulatory system
o Digestive system
o Respiratory system
 Is there a known disorder/illness in humans that disrupts the normal processes
that should occur in the system and situation that you chose? Explain what
happens in this situation and what doctors can do to help the patient maintain
a homeostatic balance.
The posters will be presented to the class, in a professional poster session
format. This will be organized in such a way that all posters will be on display, and
one of the “authors” of the poster will stand by his/her poster to offer explanation
and answer any questions of the audience. The other “author” is free to walk around
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and look at the other students’ work. After 30 minutes, the pair will switch roles. As
the students walk around the room looking at other people’s posters, they will also be
responsible for completing a peer assessment form for each poster that they view.
The teacher will assign him/her to view 1/3 of the class posters; if s/he has extra
time s/he should feel free to visit the rest of the posters of his/her choice. Students
will peer assess on how neat and clear the diagrams are, how well the presenter
answered questions about the poster (students will receive credit towards their own
poster project for asking one question of each presenter and documenting both the
question and the answer), and how much effort they think went into the project.
These peer assessments are mainly to guide the students to think critically about
viewing peers’ work, which they will need to be able to do in the field of scientific
research, and to stimulate scientific discourse between the audience and the
presenter, another authentic task that is essential to a good scientific poster
presentation.
6. Essential Questions
1. Why don’t we (as healthy individuals) overheat and get very sick when the
temperature in Kenmore reaches 110°F during a 6-day heat wave in mid-August
(assume we do not have air conditioning)?
2. How does your body physically respond to strenuous exercise? In other words, what
exactly is happening inside your body when you are running around while participating
in your favorite sport?
7. Backward Planning Sequence
1. Description of maintenance of homeostatic balance.
2. What kinds of changes occur in the body that causes an imbalance and disrupts
homeostasis.
3. What organ/tissue systems are involved in the body’s response.
4. How the body responds to these disruptions.
5. What the normal function of this organ system is.
6. How the system is regulated.
7. If the system affects metabolism, or vice versa.
8. What types of materials are transported in this system.
9. How the materials are transported to and from the cells in this system.
10. Whether or not osmoregulation is important to homeostasis in this situation.
11. How osmosis/diffusion occur.
12. How water balance is maintained in the body and in the cell.
13. How to artificially manipulate a system that is flawed due to a disorder/illness in
order to maintain homeostasis.
14. How temperature regulation occurs.