Autumn.wmf (12088 bytes) Concepts of Biology (BIOL116) - Dr. S.G. Saupe; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321;;

Study Guide for Community Interactions

Goal of the Unit:  The goal of this unit is to provide a general overview to the types of interactions that occur between species in a community.


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

  1. Understand the nature of community structure

  2. Explain various means by which species protect themselves

  3. Understand the difference between niche and habitat

  4. Explain the principle of competitive exclusion

  5. Describe succession

  6. Describe some of the lessons from studies of island biology

Required Reading:  Purves, et al, Chapter 55


Important Terms/Concepts: (can you use these conversationally?)

  • actual niche      

  • climax

  • coevolution        

  • community  

  • epiphytes

  • fugitive species    

  • interspecific     

  • intraspecific

  • mimicry

  • mutualism

  • niche   

  • niche overlap

  • niche shift

  • parasitism         

  • predator           

  • prey

  • primary compounds

  • realized niche

  • secondary compounds           

  • species abundance

  • species diversity  

  • species richness

  • succession

  • symbiosis 

  • trophic level

  • warning coloration (aposematic)


Questions for Thought and Study:

  1. Compare and contrast niche and habitat.

  2. Discuss the Principle of Competitive Exclusion.  What are possible outcomes of niche overlap?  How do each of the following examples support this concept? - Gause's study of Paramecium, Connell's study of barnacles, and the study of flour beetles and glass tubing (i.e., Tribolium)

  3. What is a community?  Give an example.

  4. Give examples of parasitism, commensalism and mutualism.

  5. Describe the Ant-acacia story as an example of mutualism.  Explain how the ants and the plants each benefit. Why don't biologists expect to find defensive chemicals in species like ant acacias.

  6. Compare and contrast primary and secondary succession.

  7. What is a xerarch succession?  hydrarch succession?  Are these examples of primary or secondary successions?

  8. What is the role of succession?

  9. Why does succession occur?

  10. What is a climax community? 

  11. Community stability is related to species diversity and habitat complexity.  Explain what this means and give an example

  12. Imagine that two similar species of zooplankton separate their niches by feeding at different depths in Lake Sag.  Prepare a graph to represent the niches of these species if one is typically found at a depth 5' and the other at 10'.

  13. What is the difference between fundamental and realized niche?  Can they ever be the same?  Can you give an example.  Which is specified in the question above?

  14. Describe the relationship between predator and prey.

  15. Compare and contrast parasitism, parasitoids, commensalism and mutualism.  Can you give examples of each?

  16. What makes for a good parasite?

  17. What is the typical outcome of species introductions?  Why?

  18. What is the distance effect in island biology?  Why does this exist?  What is the area effect?  Why does this exist?

  19. At first glance, ungulates in the Serengeti seem to occupy the identical niche.  Do they disobey the principle of competition exclusion?  Explain.

  20. What are mycorrhizae?  Are they an example of commensalism, mutualism or parasitism?

  21. Why are predator and prey populations often cyclic in nature?

  22. Give some examples of cryptic coloration.  How do these species protect themselves?  Are they typically poisonous? Explain.

  23. Give some examples of aposematic (warning coloration).  How do these species protect themselves?

  24. Give some examples of mimicry.  Compare and contrast Batesian and Mullerian mimicry.

  25. Describe the blue jay - monarch - viceroy story.  Which type of mimicry is this? 

  26. Check out the Community Questions

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Last updated: April 23, 2004        � Copyright by SG Saupe