UTPA STEM/CBI Courses/Surface Area to Volume Ratio

Course Title: General Biology 2

Lecture Topic: Surface Area to Volume Ratio

Instructor: Matthew Terry

Institution: UTPA

Backwards Design

Course Objectives

• Primary Objectives- By the next class period students will be able to:
  • Know what happens to surface area as volume increases
  • Be able to give real world biological examples of the consequences of this
  • Be aware of ways organisms get around this issue
  • Predict habitat of aquatic insects based on morphology

• Sub Objectives- The objectives will require that students be able to:
  • Calculate surface area and volume
  • Think of examples from the biological world

• Difficulties- Students may have difficulty:
  • Graphing

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
  • Determine if a structure functions as an organ for diffusion or temperature regulation based on morphology
  • Be able to explain how specific behaviors compensate for these principles

Model of Knowledge

• Concept Map
  • What is surface area?
  • What is volume?
  • How are volume and surface area connected?
  • How does the shape of an animal affect these?
  • Real world examples (Emperor penguins, lungs, gills, small intestine, whales, etc.)
  • How are diffusion and heat conservation connected?

• Content Priorities
  • Enduring Understanding
    • Surface Area to Volume ratio increase exponentially
    • This phenomenon affects the shape and behavior of organisms
  • Important to Do and Know
    • Calculate and graph surface area and volume for cube as it increases in size
    • Use EXCEL to observe the relations of this change
    • Demonstrate diffusion using agar and dye
    • Demonstrate cooling of water in different volumes and shapes
  • Worth Being Familiar with
    • How do insects compensate for this?
    • What organs are shaped to use this phenomenon?
    • Penguin example

Assessment of Learning

• Formative Assessment
  • In Class (groups)
    • Compare measurements and graphs of different groups
    • Get examples of organs and/or organism behavior that demonstrate this principle
    • Place aquatic insects in their environment based on how they get their oxygen
  • Homework (individual)
    • Complete and turn in a lab report
• Summative Assessment
  • Weekly Quiz
  • Final Exam

Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

• Know what happens to surface area as volume increases
• Be able to give real world biological examples of the consequences of this
• Know ways that organisms get around this issue
• Predict habitat of aquatic insects based on morphology

The objectives will require that students be able to:

• Calculate volume and surface area
• Use excel
• Make logical predictions based on the learned concepts and observation

THE CHALLENGE

It's Not Easy Being Big: How does the relationship between surface area and volume impact living organisms?

GENERATE IDEAS

In class brainstorming and discussion

MULTIPLE PERSPECTIVES

• Emperor Penguin example
• Tissue pictures

RESEARCH & REVISE

Written and oral feedback from students

TEST YOUR METTLE

• Open oral questions to the class
• Written quiz at the beginning of the next lab

GO PUBLIC

Groups present their graphical results to the class

Pre-Lesson Quiz

1. How do you calculate the volume of a cube?
2. How do you calculate the surface area of a cube?
3. What happens to the surface area of a cube as you increase its size (volume)?
4. Does this occur at the same rate as you increase volume?
5. Would this process change if you used a different shape, such as a sphere?
6. What cools faster, 100 ml of water or 1000 ml of water?
7. How might you slow the rate at which the water cools?
8. Name an organ for which diffusion is a major part of its function.
9. Name one strategy that organisms use to slow the amount of heat they lose.
10. Why does a kangaroo lick its arms?

Test Your Mettle Quiz

1. Which graph best represents the surface area to volume ratio of an elephant as it grows from a baby to an adult?
2. What is the function of the alveoli in your lungs?
3. How does asthma interfere with this function?
4. Why are there no small marine mammals?
5. Why are there small marine animals that are not mammals?
6. What are three forms of insulation for arctic animals?
7. How do emperor penguins survive the Antarctic winters?
8. Gills in the diagram below are colored red. Which of the insects comes from an oxygen poor environment?
9. Why are there no large insects?
10. Describe the phenomenon of counter exchange and how it helps endotherms maintain their body temperature.