A Collaborative Effort
Title: EduWeblabs on Photosynthesis and Lake Profiles
Class: Environmental Botany
Grade: 11-12
Timeframe: 3 days
Knowledge Gap Topic
What are various locations of niche/habitats/organisms found in
streams/watersheds and how are they related to each other?
Subject Matter/
Key Vocabulary
Basic equation of photosynthesis related to autotrophs and how that
affects gases in streams
Relating CO2 use to growth and O2 production to light intensity and
temperature of water
Identify the various microhabitats of a stream/lake and relate the physical
factors to the biota found in each habitat.
Essential Question/
Over-Arching Concept/
Key Understanding
Get a basic idea of how dissolved oxygen relates to temperature of water
Curriculum Connections
 OGT standards
 Local standards
Earth Science 9-10: D; 11-12: B
Life Science 9-10:D,G; 11-12: E
Performance Objectives/
Behavioral Objectives
PO1) Students will be able to describe in everyday terms and chemical
equations the processes of photosynthesis and respiration
PO2) Students relate various micro-habitats of streams and ponds to
these processes and the animals found there
BO1) Students should be able to look at various areas or levels of a
stream or pond and be able to determine the basic processes going on
there (tropholytic vs. trophogenic zones, etc.)
BO2) Students should be able to discuss how man-made products may
affect these processes (e.g., phosphorous overloading causing increase in
algae)
Handouts: Directions for each of the following three EduWeblabs:
1) Elodea Photosynthesis
2) Duckweed Growth
3) Thermocline Lab
Materials
Introduction
 focus event
 varies with teacher
Development
 major parts of unit/
lesson
Equipment: Internet connection and subscription to http://eduweblabs.com/
Discuss basic food pyramids and the concepts of autotrophs (producers)
and heterotrophs (consumers). Introduce basic equations for
photosynthesis and respiration and demonstrate that carbon is recycled
but energy is not.
Labs:
1) Do the labs in the order above. In the Elodea lab, plot data and plot a
best fit line.
2) In the Duckweed lab, change the rates of CO2 and then run a t-test on
the results to show a significant change when CO2 levels are increased.
3) In the Thermocline lab, plot all the seasons for temperature to
demonstrate thermocline occurring mainly in summer and relate
temperatures to oxygen % and where fish might be found. Relate to
Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach
USDA-CSREES National Integrated Water Quality Program
tropholytic and trophogenic zones and what types of organisms are found
in each.
Rigor/Relevance Quadrant(s)
 link to rigor/relevance
document
A: Must use terms correctly … autotroph, heterotroph, producer,
consumer, decomposer, pyramid, photosynthesis, respiration, tropholytic
and trophogenic zones, thermocline.
B: None
C: Write equations for photosynthesis and respiration; plot best fit lines
relating light intensity and oxygen production; run t tests for significance in
oxygen production of plants with varying amounts of CO 2
D: Forecast oxygen production with amounts of light not tested. Discuss
where autotrophs would most likely be found in a lake and relate to
streams.
Product/Artifacts/Student
Evidence of Understanding
Graphs which include best fit lines and R squared values
Graphs comparing oxygen production and significance of differences
Diagram of lake profile, locating the following: benthic, limnetic and littoral
zones; tropholytic and trophogenic zones
Accommodations
 plan B
 differentiated instruction
Establishing good teams that work together well is essential here. It takes
two or three people working on different aspects of these labs to put
everything together. Important to give reflection time before they turn it in.
Perhaps adding some reflective questions at the end relating all concepts
would help.
Formative
Assessment/Feedback
 measure of progress
Use questions during lecture to determine understanding of
photosynthesis and respiration equations.
Pop quiz (formative only) on equations
Final Evaluation
 project rubric
 oral or paper quiz/test
 portfolio
Periodic checks of student data/graphs while doing the EduWeblabs
Students write an essay on the “Carbon Cycle”, illustrating how autotrophs
and heterotrophs are intertwined in their use and/or production of CO 2 and
O2
Student use a best fit line to predict value of oxygen produced when
another value of light intensity is used.
Teacher Reflection
 complete after lesson
Some students struggled with best fit lines … not so much the concept as
just the process of using excel to calculate them. It takes some several
efforts on the essay to really communicate the cyclical nature of CO2 and
O2 being used by auto and heterotrophs. With lower level students
relating photosynthesis and respiration to various trophic levels makes
sense, but they have a hard time keeping so many different concepts
connected. These labs are good as they reinforce each other.
Designers/Email: Fred Donelson (fdonelson@gjps.org)
Additional Comments: These labs help solidify student understanding of photosynthesis and respiration and
how they complement each other. The thermocline profile lab helps student relate temperature of water to
oxygen content in a lake which can then be related to streams and how oxygen enters streams in different ways.
These labs are only available with a subscription to eduweblabs.com.
Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach
USDA-CSREES National Integrated Water Quality Program
Photosynthesis EduWeb Lab
Summary:
Students vary light intensity via distance and measure O2 production by autotrophs. Ideas to reinforce
are photosynthesis and importance of autotrophs in making oxygen at the base of food pyramid. It also
allows kids to plot data, use regression analysis and evaluate lines for best fit and then use best fit lines
for predictions.
Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach
USDA-CSREES National Integrated Water Quality Program
Duckweed Growth EduWeb Lab
Summary:
Students grow duckweed in both controlled conditions and with extra CO2, showing its importance in
photosynthesis. Students use Student’s “t” Test to determine if differences are significant.
Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach
USDA-CSREES National Integrated Water Quality Program
Thermocline EduWeb Lab
Relating temperature to dissolved O2 in different seasons
Summary
Students plot temps in different seasons, then predict where fish will be based on their predictions of
where oxygen is. Major idea is to help students to realize that water is most dense at 4 degrees Celsius,
and that cooler water holds more oxygen than warmer.
Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach
USDA-CSREES National Integrated Water Quality Program
Designing Watershed-based Education and Extension Efforts through a Mental Models Research Approach
USDA-CSREES National Integrated Water Quality Program