Population Dynamics Based on Resource Availability & Founding Effects: Live & Computational Models

Samuel Potter, Rebecca M. Krall, Susan Mayo, Diane Johnson, Kim Zeidler-Watters, Robin L. Cooper
Type Category
Instructional Materials
Experiment/Lab Activity , Interactive Simulation , Lesson/Lesson Plan , Model , Numerical/Computer Model , Simulation
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



This article in the May 2016 issue of The American Biology Teacher describes three modules designed to help students engage in three-dimensional learning as they explore the phenomenon of natural population growth. Using fruit flies as a model organism, the three modules are designed to motivate students to investigate their ideas about how initial size of a population, food availability, and space each impacts population growth. Teachers may use one or more of the modules, or adapt any of them to best match their curricular design. Once familiar with the basic setup of each module, students may generate questions or make claims about other environmental factors to test. All three modules may be done as computer simulations using a provided modified version of a NetLogo simulation. Depending on students’ prior learning, data analysis may be done either manually, using a spreadsheet program or by using JoinPoint, a free statistical analysis software program. Suggestions are made for ways to either modify or extend the lesson. The lesson is supported with additional resources, including student handouts, spreadsheet templates, NetLogo information, and demonstration videos, available at the website: http://web.as.uky.edu/Biology/faculty/cooper/Population%20dynamics%20examples%20with%20fruit%20flies/TheAmericanBiologyTeacher-PopulationDynamicsWebpage.html

Intended Audience

Educational Level
  • High School
Access Restrictions

Available by subscription - The right to view and/or download material, often for a set period of time, by way of a financial agreement between rights holders and authorized users.

Performance Expectations

HS-LS2-1 Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales

Clarification Statement: Emphasis is on quantitative analysis and comparison of the relationships among interdependent factors including boundaries, resources, climate, and competition. Examples of mathematical comparisons could include graphs, charts, histograms, and population changes gathered from simulations or historical data sets.

Assessment Boundary: Assessment does not include deriving mathematical equations to make comparisons.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
This lesson encourages students to engage in three-dimensional learning as they investigate a claim to make sense of the phenomenon of natural population growth. Teachers may want to find real world examples of this phenomenon, such as the growing global human population, to engage students prior to doing the lesson. Presenting the students with a global population curve, for example, and asking them to think about what may happen, including possible constraints, will help students to apply the results of the lesson to a real world phenomenon. Another way to engage students would be to look for a population that is growing within their local environment, such as a pest species. The lesson describes three different modules that students can use to answer questions about how different factors may affect the growth of populations. Each module produces data which students can use to create mathematical and/or computational representations, depending on what tools they use to represent the data. Teachers will want to explore the suggested resources prior to doing the lesson to see which approach best fits the experience and prior knowledge of their students. Teachers can modify the modules, use just one module and extend it, or ask the class to generate additional questions they may have, once they understand the setup and potential of the module they are using. Carrying capacity is not explicitly mentioned in the lesson, although the emphasis is on factors that may limit population growth. Teachers may want to challenge students to connect their results with the fruit fly modules to the real world examples presented at the beginning of the lesson.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
The strength of this lesson is the generation of mathematical and/or computational models to help students explain population growth. Its strength may also be a potential weakness, if teachers do not allow students to ask their own questions to generate an experimental design, or to make a claim and decide how to manipulate the variable of choice to support their claim with evidence. Teachers may therefore want to present the development of these models as a framework for inquiry, which allows students to ask and answer questions. Teachers may want to make explicit the practice of engaging in argument from evidence. Students could then make claims, use the models to provide evidence, and reason scientifically to defend their claims, or to critique the claims of other students.

This resource was not designed to build towards this science and engineering practice, but can be used to build towards it using the suggestions provided below.

Comments about Including the Science and Engineering Practice
Prior to using a module, teachers may want to ask students to provide an explanation or make a claim about the expected results. Each module produces counts of fruit flies, either the number of pupae or the number of adults, at the end of the experiment. This data may be entered into either tables or Excel spreadsheets. The students may then either use the suggested software program, Joinpoint, or use their own graphs or calculations to represent their results, depending on their experiment. The link at the end of the article provides sample spreadsheets as well as sample data which teachers may want to look at prior to using the lesson.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
Fruit flies are hardy, easy to raise, and have a short life cycle. Using fruit flies as a model will provide students with opportunities to manipulate the environment and resources, as well as vary the number of flies in the founding population, as they explore their questions or provide evidence to support their claims about population growth. As mentioned previously, carrying capacity is not explicitly mentioned in the lesson, although the emphasis is on factors that may limit population growth. One challenge for teachers will be to encourage students to extend their thinking to natural populations. Using local natural population phenomenon may help students to connect their results to the real world.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
In each module, students manipulate a particular factor (the cause) to see what happens to the size a fruit fly population can grow (the effect). The factors in the modules are either the number of females in the initial population, food availability, or space availability. NetLogo simulations provide a time advantage over live models by quickly providing answers to students’ questions. Using simulations may help students to explore ways to differentiate cause and correlation. However, teachers may want their students to use live models first; the article recommends that student experience the physical phenomena first because “computer simulations remove the personal interaction of running live experiments and can leave students unclear about the authenticity of simulation outcomes” (p. 400).

Resource Quality

  • Alignment to the Dimensions of the NGSS: Three learning modules are presented that provide students with authentic experiences in modeling factors that cause populations to be limited. Students create mathematical representations to support explanations.

  • Instructional Supports: This resource offers extensive support for teaching and learning. Prior to publishing, the lesson was implemented in over 300 classrooms - 200 middle school classrooms, and 100 high school classrooms. The authors share many specific outcomes and recommendations from these experiences so that teachers can more successfully implement and scaffold the appropriate modules in their classrooms. For example, some of the specific difficulties with implementing the modules are addressed, along with potential solutions. Modifications of the modules are suggested, as well as extensions of the modules for more advanced students. For students, the lessons provide scientifically accurate and grade-appropriate models to help build understanding of the disciplinary core idea and support three-dimensional learning.

  • Monitoring Student Progress: The authors state that assessment information will be available in a later publication. However, the modules themselves do produce direct, observable evidence of student learning. Teachers can also make their students’ learning more explicit by using a variety of ways for students to explain the phenomenon they are investigating. Opportunities such as sharing, peer reviews/critiques, and science journals will help make student learning more visible and allow teachers to modify instruction in real time. If teachers emphasize engaging in argument from evidence, then students will reveal their thinking through this practice.

  • Quality of Technological Interactivity: The NetLogo link was not user friendly, and it is recommended that teachers explore using this option prior to class time. Alternative NetLogo simulations that are also appropriate to support this resource are “Rabbits Grass Weeds” (https://ccl.northwestern.edu/netlogo/models/RabbitsGrassWeeds) and “Wolf Sheep Predation”: (https://ccl.northwestern.edu/netlogo/models/WolfSheepPredation)