Teachable Tidbit: Introduction to Population Modeling Kristen Epp Ross Koning Alexander Lloyd Janet Morrison

Context Introductory ecology students 4-week unit on modeling changes to population size Scaled for class of < 30 students

Context Timing: mid-semester after life history unit Prior student knowledge Ecological and evolutionary importance of populations Quantifying characteristics of populations such as reproduction, mortality/survivorship, population size changes

Unit Learning Goal Students will understand that changes in population size can be described and predicted using mathematical equations and graphs. F For example: Exponential population growth

Unit Learning Objectives List and define basic ecological factors affecting population growth. Articulate the mathematical relationships between the components of a population model. Develop a mathematical representation (equation) of population growth with graphical illustration. Modify basic models to include biotic interactions of intra- and interspecific competition and exploitation. Evaluate the validity of models using real data.

Unit Learning Objectives List and define basic ecological factors affecting population growth. Articulate the mathematical relationships between the components of a population model. Develop a mathematical representation (equation) of population growth with graphical illustration. Modify basic models to include biotic interactions of intra- and interspecific competition and exploitation. Evaluate the validity of models using real data.

Homework Prequel… Students will have completed a life history problem on tribbles prior to class View Star Trek clip on tribble invasion Complete homework life table problem on tribbles https://www.youtube.com/watch?v=p4wM5KvUGEc

Introduction to modeling population change Beginning of teachable tidbit!

How did Spock know the exact number of tribbles that were on the Enterprise? 1. Allow students to brainstorm using think-pair-share about the answer to the Spock question.

Class Today Learning objectives: List and define basic ecological factors affecting population growth. Begin to articulate the mathematical relationships between the components of a population model.

Factors that Change Population Size What factors might change the size of a population? Write two factors on your notecard. Share the factors with the class. Students write down two factors they think matter. Create a class list on board Instructor condenses list to a few consistent things including births, deaths, competition for resources, predation, etc.

Factors that Change Population Size Births Deaths Competition Predation Immigration Emigration

Build a diagram/concept map of effects Births Deaths Competition Predation Immigration Emigration Write Population Size (N) Use only these labels/arrows to make connections: Increases Decreases

Concept Maps Look at concept maps from other groups Does yours look the same? What’s different? Revise concept maps as needed. To scale up: swap papers with neighbor group to compare. Ask students why questions to simplify and draw answers into births and deaths. E.g. why do you think that competition decreases population size? Why do you think that predation decreases population size?

Concept Map (Example) Births Immigration Emigration Population Size Increases Decreases Increases Emigration Population Size (N) Competition Decreases Increases Decreases Predation Increases Deaths

End of Tidbit How can we translate this concept map into a mathematical equation?

Unit Learning Objectives List and define basic ecological factors affecting population growth (i.e. births, deaths, migration, population size, time, carrying capacity, biotic interactions, etc.). Articulate the mathematical relationships between the components of a population model. Develop a mathematical representation (equation) of population growth with graphical illustration. Modify basic models to include biotic interactions of intra- and interspecific competition and exploitation. Evaluate the validity of models using real data.

Questions?