Autumn.wmf (12088 bytes)Introduction to Organismal Biology (BIOL221) - Dr. S.G. Saupe; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321;;

Study Guide:  Form & Function

Objectives:   Upon completion of this unit, you should be able to:

  1. Describe what is meant by a surface-to-volume ratio
  2. Be able to calculate the surface area, volume and s/v ratio for a square or rectangle
  3. Describe the biological significance of s/v ratios.
  4. Describe the relationship of form and function
  5. Explain how physical laws constrain animal form.
  6. Explain how the size and shape of an animal's and plant's body affect its interactions with the environment.

Readings/Study Materials:

  1. parts of Chapter 40
  2. online form and function notes
  3. Surface/volume homework in Moodle
  4. Presidential Notes - provided in class
  5. Bonner (2006) article - available in public folder; supplemental

Definitions:  can you use the following terms conversationally?

  • anatomy
  • form
  • function
  • morphology
  • physiology
  • surface area
  • volume
  • surface/volume ratio
  • Reynold's number (not on exam)
  • generation time  (not on exam)
  • life span  (not on exam)


  1. be able to answer questions such as those in the homework assignment.
  2. list the hierarchy of biological organization.  Can you give an example of each level
  3. identify two major themes that will run through our course this year.
  4. define physiology, morphology, anatomy
  5. what does it mean that form and function is an evolutionary compromise or trade-off?
  6. be able to calculate the surface area, volume and surface/volume ratio of a cube
  7. explain what it means that the surface area increases by the square of the linear dimension and volume increases by the cube.
  8. why are surface/volume ratios important.  Provide some examples.
  9. How does motility relate to surface/volume ratio?
  10. what are some form changes that accompany getting larger?
  11. What is the relationship between body size and basal metabolic rate.  Explain why it exists.
  12. What determines the upper size limit for an animal?
  13. What determines the lower size limit?
  14. Explain why leaves are broad and flat.
  15. According the Guinness Book of World Records the tallest living human female is 7 feet 7 � inches tall.  Using our assumption that a 5 foot woman weighs 110 pounds, how much do you predict this woman weighs?  __________.  (note:  her actual weight = 462 pounds) Show your work.
  16. Why do elephants have large, flat ears?
  17. Explain why roots have "hairs."
  18. Explain why the shape of animals is basically "spherical", whereas plants and fungi are "filamentous".
  19. Explain why small animals have a higher metabolic rate than large animals.
  20. Explain why shrews are voracious feeders.
  21. Explain why cats can fall off tall buildings and survive. Why do people splat?
  22. Explain the advantages/disadvantages of block vs. cube ice.
  23. Describe the scientific inaccuracy in the episode of Goldilocks and the porridge.
  24. Explain why lungs, gills and intestines have the shape they do.
  25. Medieval churches were often built in the shape of a crucifix. Explain why.
  26. The earth is geologically active (has a molten core) but the moon is apparently no longer geologically active. Explain why using S/V ratios.
  27. Why are there few small animals in the arctic?
  28. Explain how S/V ratios relate to the form of plants that have evolved in mesic, xeric and hydric environments.
  29. Explain why the cells of the spongy layer of a plant leaf are irregularly shaped.
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Last updated: January 12, 2009        � Copyright by SG Saupe