Bio122 Ecology F15
Lecture #9 (10/22/15): Mutualism (Ch15); Communities (Ch 16)
I. Mutualism (Ch 15)
A. Defined (+/+)
B. Types
1. Trophic
2. Habitat
3. Service
C. Costs & Benefits
D. Ecological Consequences
1. Abundance
2. Distribution
3. Diversity
4. Species Interactions
II. Communities (Ch 16)
A. Defined
B. Categorizing communities
1. Particular area
2. Taxonomic group
3. Guild
4. Functional group
C. Community structure
1. Trophic relationships
2. Species diversity
a. Diversity indices
b. Rank abundance curves
c. Species accumulation curves
D. Processes that shape community structure: Interactions
1. Types of indirect effects
2. Interaction strength
3. Dominant species
4. Ecosystem engineers
5. Keystone species
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Study Questons
1. Is the net effect in a mutualism positive, negative, or neutral for each member of the
relationship?
2. List each of the 3 types of mutualism and provide an example for each.
3. Provide an example of a situation in which a mutualism is no longer beneficial for one of the
members and so the relationship is constrained or terminated.
4. Briefly discuss how mutualism can impact each of the following: abundance of a species,
geographic distribution, diversity, species interaction.
5. Define community.
6. What makes a community more than the sum of its parts?
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Bio122 Ecology F15
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Lecture #9 (10/22/15): Mutualism (Ch15); Communities (Ch 16)
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List & briefly describe 4 different approaches to characterizing a community.
What is the difference between species richness, species evenness, and species diversity?
What is a species accumulation curve and why would you use one?
Describe a rank-abundance curve, noting what is plotted along each axis. How would the curves
differ for communities with relatively higher vs. lower species richness and for higher vs. lower
species evenness?
What 2 pieces of information are used in calculating species diversity (such as the Shannon
index)?
What would cause a community with low species richness have a higher species diversity than
another community with higher species richness?
Define trophic cascade. Provide an example.
Define: direct interaction, indirect interaction, foundation species, ecosystem engineers, and
keystone species. Provide an example for each.