Living Environment
Student Work
Homeostatic Maintenance and External Response #17
Lesson Title
Name:
Period ______
Laboratory Experience ##
Worth ### Lab Minutes
Date :
Bridge
We have taken a look at a lot of different life processes and how they
affect heterotrophic organisms, like humans, but how do these processes
affect plants?
1. Do they have to regulate or maintain homeostasis like animals or
even unicellular organisms?
Objective:
Compare
regulation in
plants to
regulation in
humans
2. Do they have a nervous system?
3. What about an endocrine system that releases hormones?
Essential
Question:
Do plants
regulate or
maintain
homeostasis the
same as
unicellular and
multicellular
heterotrophic
organisms?
Explain why or
why not.
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Living Environment
Student Work
Homeostatic Maintenance and External Response #17
Mini Lesson
Directions: Read passage and go back and answer the questions from the bridge.
Unicellular organisms do not have the same structures for maintaining
homeostasis as multicellular organisms but they use the same functions. For
example, where fish use the osmotic gradient to maintain water balance which
evolved from whether they were in salt or fresh water, a unicellular organism, like
our paramecium, will use a specialized organelle called a contractile vacuole, to
gather up the excess water and spit it out of the cell through the cell membrane.
Unicellular organisms also do not have complex endocrine systems to help
regulate cellular communication or complex nervous systems for electrical
impulses, but the nucleus and cell membrane have structures built into them to
code for, produce and receive hormones and the cytoplasm will deliver electrical
impulses since they don’t have to go very far.
But many plants are multicellular and some even larger and more complex than
even a human or our largest animals. In fact, the second largest organism in the
world is a plant: a giant sequoia found in Sierra
Nevada, Californa. The largest is a fungus found in Oregon called Armillaria
ostoyae that spans 2200 acres (3.4 miles) and is approximately 8,000 years old.
But when I think of plants or fungi, I don’t think of them like I do animals, but they
are still living things, so they must be able to find that balance.
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Living Environment
Student Work
Homeostatic Maintenance and External Response #17
Work Period
Task:
 You will be investigating the organization of plants and comparing them to animals. In
these comparisons, consider all of the life processes we have looked at so far with
regards to unicellular organisms and multicellular organisms, specifically humans.
 You will be split into groups. You will investigate the life process you have been assigned
and prepare a presentation for the class. Plants have even more variety than animals
throughout evolution, so look for things that are common between the plants to present to
the class. (For example, some plants have large flat leaves like trees in the rainforest
while some plants that have leaves that are very thin and prickly like a cactus…. What do
those leaves have in common).
Group Assignments:
circulation
nutrition
excretion
digestion
synthesis
communication
cellular respiration
regulation of water/solutes (think of diffusion/osmosis)
respiration (like the respiratory system in people)
When you present, you need to provide enough information for your classmates to be
able to discuss the following table:
Homeostasis in Different Organisms
Notes to the Students: While you do this, you may notice that the processes in plants may have
the same function but a different process name is assigned to it or it may be the same process
but functions a little differently.
Use the Life Process column on the right to identify if that process has a different name (for
example, plants have internal water regulation and it is called the same but they have features
that control the interface between internal and external regulation and it has a different name,
same function).
If it is the same life process (for example, communication in plants is called the same thing as
communication in animals but it functions a little differently) then just fill in the name in the right
column to match the column on the left.
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Living Environment
Student Work
Homeostatic Maintenance and External Response #17
Homeostasis in Different Organisms
Life
Process
Unicellular
Animals
Plants
Life
Organisms
Process
Structure Function Structure Function Structure Function
Circulation
Nutrition
Synthesis
Digestion
Regulation of
water/ solutes
Cellular
respiration
Excretion
Respiration
Communication
Summary
Do plants regulate or maintain homeostasis the same as unicellular and multicellular
heterotrophic organisms? Explain why or why not.
Closing
Fungi are a not quite plants and not quite animals. Do you think that they perform functions
closer to that of plants or that of animals? Explain your answer
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Living Environment
Student Work
Name:
Homeostatic Maintenance and External Response #17
Period ______
Date :
Independent Practice
Reading and questions on fungi life processes
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Living Environment
Student Work
Name:
Homeostatic Maintenance and External Response #17
Period ______
Date :
Title of Lab: ______________________________________________________
Exploration
Use this space to record observations that relate to the question being investigated. Also record
researched facts that might relate to the investigation as well.
Question
Record your question that you will be investigating here. It is best to write it in a “Does
__________________ affect ________________? Format so the variables are easy to identify (first
line is always the independent variable, second line is always the dependent variable)
Identify your Variables
Independent Variable:
Dependent Variable:
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Living Environment
Student Work
Homeostatic Maintenance and External Response #17
Prediction/Hypothesis
Based on the question that you asked, record your thoughts on what the result will be and why. Use
the “I think ___________________________________, because ______________.” format.
Experimental Design
List the materials that you are going to use and the procedure (steps) you are going to take to test your
hypothesis.
Materials:
Procedure:
Data Collection
Use this space to organize and collect your data. Remember, data can be qualitative (descriptions,
words, observations) as well as quantitative (numbers, values). Use both kinds of data when you can.
Organize your data into a table with a title, make a graph whenever you can, and use the variables to
help you do this!
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Living Environment
Student Work
Homeostatic Maintenance and External Response #17
Data Analysis
Put your data into words. This will be a relationship of your variables: what happened to the dependent
variable when you changed the independent variable?
Evaluation
This is where you talk about your experiment. Discuss how your results compare to your hypothesis:
do you agree or disagree with your original thoughts and use evidence from your experiment to back
this up. Second, discuss sources of error (at least 2), or things that could have gone wrong in your
experiment. Finally, develop a further investigation question: based on what you found out in this
experiment, what else do you wonder about? Again, use your “Does ________ affect __________”
format for this question.
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