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

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

3. 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

4. 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

5. 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.

6. 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.

7. 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

8. Introduction to modeling population change
Beginning of teachable tidbit!

9. 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.

10. 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.

11. 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.

12. Factors that Change Population Size
Births
Deaths
Competition
Predation
Immigration
Emigration

13. 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

14. 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?

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

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

17. 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.

18. Questions?