Teaching Notes

Grade Level

High school students (middle school students if all data provided and only graphing required)

Learning Goals

After completing this unit, users will be able to:

  • Manipulate data in a spreadsheet to produce graphs.
  • Use MS Excel graphs and statistical functions (average, standard deviation) to evaluate changes in biological system responses to climate change
  • Generate and compare multiple sets of time series temperature data (seasonal or annual).
  • Gain familiarity with the lexicon of climate research vocabulary.


Climate change is affecting the seasonal timing for many different plants and animals. Gibbs & Breisch (2001) found that the timing of spring emergence and reproductive cycles of several species of frogs in Ithaca, NY have changed with the climate changes that occurred over the 20th century. Amphibians in temperate regions are highly sensitive indicators of biotic response to climate change. Frogs, especially those that breed early in the spring season, are especially sensitive to increases in winter and spring temperatures.

Expecting students to use and interpret phenology data over time as the climate has changed will help them to see for themselves that ecosystems are responding to climate changes.

Key Concepts and Vocabulary

Gametogenesis: The development and maturation of sex cells through meiosis (cell division necessary for sexual reproduction)

Phenology:  The scientific study of periodic biological phenomena, such as flowering, breeding, and migration, in relation to climatic conditions.

Background Information

There is significant evidence that climate change is affecting the seasonal timing for many different plants and animals (Gibbs & Breisch 2001). Many studies have been done in Europe for decades around the calling and first appearance dates of frogs and toads but only one similar study has been conducted in the United States, in Ithaca, NY. Gibbs & Breisch (2001) found that the timing of spring emergence and reproductive cycles of several species of frogs in Ithaca have changed with the climate changes that occurred over the 20th century (red arrow on New York map).

The timing of frog breeding has been studied because amphibians in temperate regions are highly sensitive indicators of biotic response to climate change. The critical eight months of amphibian gametogensis (overwintering, emergence, courtship, and spawning) occurs in the period extending from November through June. Frogs, especially those that breed early in the spring season, are especially sensitive to increases in winter and spring temperatures.

One way to study the timing of frog reproduction is to listen for their mating calls in the spring. Wright (1914) studied frog habitat and reproduction in the Ithaca area and reported emergence dates and mating call timing during the first decade of the 1900’s. Gibbs & Breisch (2001) compared Wright’s early data to similar data compiled in the New York State Amphibian and Reptile Atlas Project (NYSA RAP) for 1990–1999. Their comparison found that mating calls are happening earlier in the spring for four of the seven species studied.

Learn More:

  • North American Amphibian Monitoring Program (NAAMP)
    • Review additional data on frog  locations and numbers
    • Raw data for variables such as air temperatures, species, calling index, snow cover, car count, etc.
    • Species detection and richness maps. 
    • Module extension idea – monitor frogs in your region and report data to the NAAMP
  • USGS Frog Quiz
    • This site provides audio clips for different frogs living in the state chosen by the user
    • An effective tool if planning on going into the field to monitor frogs
  • Frog calling videos (can also google “frog call videos” for more)

Present and Historical Data:

Predictive Tools and Data

  • Northeast Climate Data
    • Historical and predicted values for temperature and many climate indicators
    • Results of Northeast regional climate change models for A1 (worst case) and B1 (GHG mitigation) scenarios available for download into ASCII files (and summarized in the attached MS Excel workbook)

Instructional Strategies

General Approach

This project module uses monthly average temperatures for the Ithaca NY, region and calling dates for several frog species. The students review temperature data to see how the climate in this region has changed over the 20th century, especially during months critical for frog reproduction. They then review changes in calling dates to determine a trend. Depending on the students’ quantitative skills, they can be expected to use some basic MS Excel functions (average, standard deviation, linear regression) and create graphs to illustrate changes.

It may be advantageous to have students work in small groups so that students less familiar with the software used in the module could be teamed with more experienced computer users.


Anticipatory Set Students should have some familiarity with general concept of climate change before beginning. This module will help to connect the abstract notion of a change in a few degrees of temperature can have an impact on ecological systems. Review of basic frog phenology and mating calls (see links to excellent videos and audio web resources) so that the students understand critical conditions.


  1. Review the information about frog species and the North American Amphibian Monitoring program to understand the breeding behavior and typical dates for a couple of the frog species. (~1 day)
  2. Optional: Have students read the paper by Gibbs & Breisch (2001) to explore what scientists have already done and found. (could also do this after students analysis to compare the students’ findings and interpretation to scientific findings)
  3. Students should follow the Student Instruction and Worksheet document to evaluate temperature and frog calling dates and any correlation between these values (~2 days).
    1. Temperature and frog calling dates are included in the attached MS Excel workbook.  Review these data and generate plots to answer the questions in the student worksheet.
    2. Use the Northeast Climate Data to review predicted temperature data for the Ithaca area for specific months of interest at the end of the 21st century. Note – data from this web site are also included in the attached MS Excel spreadsheet.  You can provide these data through the spreadsheet or expect the students to use the website.  Use of an external website to find information is encouraged, but might take an extra class period. A tutorial for using the Northeast Climate Data site is available.

Students should submit their MS Excel spreadsheet and completed spreadsheet or write their work as a laboratory report.

Closure Review the students’ findings and the limitations in this type of analysis. Discuss how their results might affect their attitudes towards the reality and consequences of climate change.

Learning Contexts

This class is very appropriate for a biology class, where the emphasis can be on the phenology and changes in ecosystems or in an environmental science classroom where more emphasis can be on the consequences of climate change.

Science Standards

(NYS MST, 1996 (commencement level))

Standard 1: Analysis, Inquiry, and Design

Mathematical Analysis:

  1. Deductive and inductive reasoning are used to reach mathematical conclusions.

Scientific Inquiry:

  1. The central purpose of scientific inquiry is to develop explanations of natural phenomena in a continuing, creative process.
  2. The observations made while testing proposed explanations, when analyzed using conventional and invented methods, provide new insights into phenomena.

Standard 2: Information Systems

  1. Information technology is used to retrieve, process, and communicate information and as a tool to enhance learning.

Standard 3: Mathematics (varies - depends on the rigor of math used by teacher)

  1. Students use mathematical modeling/multiple representation to provide a means of presenting, interpreting, communicating, and connecting mathematical information and relationships.
  2. Students use ideas of uncertainty to illustrate that mathematics involves more than exactness when dealing with everyday situations.
  3. Students use patterns and functions to develop mathematical power, appreciate the true beauty of mathematics, and construct generalizations that describe patterns simply and efficiently.

Standard 4: Science - Living Environment

  1. Individual organisms and species change over time.
  2. The continuity of life is sustained through reproduction and development.
  3. Plants and animals depend on each other and their physical environment.
  4. Human decisions and activities have had a profound impact on the physical and living environment.

Standard 5: Interconnectedness -Common Themes

  1. Models are simplified representations of objects, structures, or systems used in analysis, explanation, interpretation, or design.
  2. The continuity of life is sustained through reproduction and development.
  3. Identifying patterns of change is necessary for making predictions about future behavior and conditions.

Standard 6: Interdisciplinary Problem Solving

  1. The knowledge and skills of mathematics, science, and technology are used together to make informed decisions and solve problems, especially those relating to issues of science/technology/society, consumer decision making, design, and inquiry into phenomena.


A standard laboratory report rubric can be used to assess the student reports.

Other Resources

Amphibian data file - Amphibian Data File.xlsx

Student instructions and worksheet

Tutorial – Using the Northeast Climate Data Website to access model prediction of our future climate 

Case Study: Changes in Spring Peeper Mating Call Dates

The calculations for one frog type – Spring Peeper – were completed.  See results below and on the “Example” spreadsheet page of the workbook.



Part 1—Review frog calling date data.

Part 2— Evaluate changing temperatures

Part 3 — Extrapolate findings to expected changes in the future

(note: these instructions also included in the student worksheet)

Part 1 - Review Frog Calling Data

Frog calling data is summarized in the MS Excel spreadsheet (Amphibian Data File.xlsx).  Data is available for each year for 1900-1912.  For the decade of the 1990s, the information is provided only as a decadal average.  Data are missing for some frogs and some years.

  1. Open the MS Excel spreadsheet, and the tab for “Frog Calling Dates."
  2. Determine average and standard deviations for the 1900-1912 data to compare to the 1990-2000 averages. The standard deviation is a measure of the year-to-year variability in calling dates that would be attributed to variations in the weather. Differences in the dates between the early and late 19th century can be attributed more to changes in climate.
  3. Create a graph to illustrate the differences in calling dates.
  4. Questions:
    1. What general trends do you see in the frog calling dates between the two periods of time?
    2. For each of the frog types, evaluate if the change (number of days) in calling dates between the two periods is greater than the variation (standard deviation) within a decade.
  5. Choose one type of frog with significant changes in the dates of their mating calls for further study (note – the teacher may assign these)

Part 2 - Evaluate Changing Temperatures

Monthly average daily temperatures are included for the 20th century in the MS Excel workbook.  These data are also easily available from the NASA GISS web tool, which allows access to annual and monthly temperature data.  Follow your teacher’s instructions regarding using data already in the spreadsheet or downloading the data from the NASA GISS website. For more details, see the tutorial for instructions for accessing and downloading data for the Ithaca, NY weather station.  

  1. Open the MS Excel spreadsheet – “Avg. Monthly Temp” spreadsheet page. (or see the Excel data file you created)
  2. Using your knowledge of phenology concepts, write a hypothesis regarding the temperatures that might be related to the starting dates of the mating calls. This could be the average temperature for a month or a season.
  3. For the temperature defined in your hypothesis, calculate the average temperature over the time periods of interest (1900-1912 and 1900-2000). Compare these values. How much does the temperature change over the 20th century?
  4. Plot the date of the start of the mating calls as a function of the monthly or seasonal average temperature. Fit a linear equation to these two data points.

Part 3 - Extrapolate Findings to Expected Changes in the Future

Scientists predict that the temperature in New York State will continue to rise throughout the 21st century.  The predictions of the possible temperature rise depend on the expectations of how our populations will grow and technologies developed over this time period.  Mathematical models of our climate were used to predict temperature in New York State.  The results are available through the Northeast Climate Data Center.  Predictions are provided for two cases.  The A1 scenario is the worst case and B1 a less severe case, with expectations that we take a global and environmentally oriented approach to developing over the next century.  Use the tutorial for the Northeast Climate Data Center web site to review maps of projected temperatures for the end of the 21st century in New York State. 

  1. Open the Northeast Climate Data Center web site and register as a user (remember your user name and password!)
  2. See the graphic below (or the tutorial): Select New York State (1) and geographic plot (2); the temperature (3) and month or season (4) you determined to be the best indicator of the starting date for your frog mating call, and the time period of interest (2070-2099) (5). Click on “plot new parameters” (6) to create new charts for review.
  3. Use the color scale to estimate the future temperature for the Ithaca region (7) and record the temperature for both the A1 (worse case) and B1 (better case) modeling scenarios. Raw data for each year are also available and included in the MS Excel spreadsheet (“Predictive Temperatures A1” and “Predictive Temperatures B1”.
  4. Use the projected future temperatures and your linear equation to extrapolate and predict the amphibian calling date at the end of the 21st century. Record the date for both the A1 and B1 climate prediction models.
  5. Discussion Questions:
    1. How much will the calling dates change (# days) between the early and late decades of the 21st century. How do these changes compare to the changes over the 20th century. Discuss why these values may be different.
    2. What impact do you think these projected changes will have on frog viability in this region and ecosystem health? What other information about frog habitat and climate conditions do you think would be needed to evaluate frog viability in this region?
    3. If we see this type of impact with the frogs what other fauna or flora could be sensitive to increases in average temperatures and how might they adapt?
    4. What are the potential errors in your approach and analysis? Discuss the values and limitations of your work?
Tools Used

Microsoft Excel: A spreadsheet application is needed to analyze the data. Microsoft Excel is used in this project module and is available as part of Microsoft Office.


Tool Cost

Excel is part of the suite of Microsoft Office software. Students and educators may be able to purchase this software at a reduced cost. The Student and Home Edition is sufficient for use in the Earth Exploration Toolbook chapters.

Data Set

Northeast Climate Data

This free database provides historical data and projections of changes in temperature, precipitation, relative humidity, and snow cover for the U.S. Northeast that can be expected over the coming century under higher (A1fi) and lower (B1) emission scenarios. The data compiled here was generated as part of the Northeast Climate Impacts Assessment, a collaborative research effort between the Union of Concerned Scientists and more than 50 independent scientists from across the Northeast region and beyond.