Chapter 6: Population and Community Ecology
Reading Guide
Vocabulary
Learn the definition of each term. The italicized words are not necessarily in the textbook. The bold
words require you to know more than just the definition.
1
Population –
2
Community –
3
Population ecology –
4
Population size –
5
Population density –
6
Population distribution –
7
Sex ratio –
8
Age structure –
9
Density-dependent factors –
10
Limiting resource –
11
Carrying capacity (k) –
12
Density-independent factors –
13
Growth rate –
14
Intrinsic growth rate (r) –
15
Exponential growth model –
16
Logistic growth model –
17
Overshoot –
18
Die-off –
19
k-selected species –
20
r-selected species –
21
Survivorship curves –
22
Corridors –
23
Metapopulations –
24
Community ecology –
25
Competition –
26
Competitive exclusion principle –
27
Resource partitioning –
28
Predation –
29
True predators –
30
Herbivores –
31
Parasites –
32
Parasitoids –
33
Mutualism –
34
Commensalism –
35
Symbiotic relationship –
36
Keystone species –
37
Predator-mediated competition –
38
Ecosystem engineers –
39
Ecological succession –
40
Primary succession –
41
Secondary succession –
42
Pioneer species –
43
Theory of island biogeography –
New England Forests Come Full Circle
1. Explain why the forests of New England demonstrated resilience. You should start by defining
resilience (from an environmental perspective).
2. Describe the series of changes that occurred as the land changed from farm to forest.
3. Provide three examples of interdependency in New England forests (ways a specie relies on another)
6.1 Nature exists at several levels of complexity
4. Put the following levels of organization in order from least complex (1) to most complex (5)
a. ____ Biosphere
b. ____ Community
c. ____ Ecosystem
d. ____ Individual
e. ____ Population
6.2 Population ecologists study the factors that regulate population abundance and
distribution
5.
For each statement below, match it with the appropriate term
____ How a population occupies space
a. Size
____ The number of individuals in each age category
b. Density
____ The number of individuals per unit area
c. Distribution
____ The ratio of males to females
d. Sex ratio
____ The total number of individuals in a population
e. Age Structure
6. Label the following pictures as random, uniform or clumped distribution.
7. Label the following as density dependent (DD) or density independent (DI) factors
a. ______ A tornado
e. ______ Drought
b. ______ Amount of food available
f.
c. ______ Availability of water
g. ______ Predation
d. ______ Climate change
h. ______ Spread of disease
______ Freezing temperatures
6.3 Growth models help ecologists understand population changes
8. Fill in the following chart (careful – mine is organized differently than the book)
Trait
r-selected
K-selected
Level of parental care
Life Span
Number of offspring
Number of
reproductive events
Population dynamics
Population growth rate
Population regulation
Size of offspring
Time to reproductive
maturity
9. Fill in the following chart on survivorship curves
Survivorship Curve
Description
Example species
Type I
Type II
Type III
6.4 Community ecologists study species interactions
10. What is the difference between competitive exclusion and resource partitioning? Which one is likely to
be associated with a full niche overlap? A partial niche overlap?
11. Give an example of each type of resource partitioning
a. Temporal –
b. Spatial –
c. Morphological -
12. Fill in the following chart for species relationships
Relationship
Commensalism
Competition
Herbivores
Keystone Specie
Mutualism
Parasites
Parasitoids
True predators
Description
Specific Example
+/+, +/-, +/0
13. Competition
Identify each of the following as an example of the competitive exclusion principle, temporal resource
partitioning, spatial resource partitioning or morphological resource partitioning:
i. Several species of Warbler Birds hunt insects in the same types of trees, but each feeds
in a different part of the tree
ii. When wolves were absent from Yosemite, deer grazed many plant species so heavily
that other herbivore species were unable to establish themselves
iii. Many different species of bats use a single watering hole, but each at different times
iv. Different species of butterfly have tongues of varying lengths, each specialized to the
shape of the flowers produced by the plants it feeds on
v. Invasive species that out-compete native species for key resources often drive the
native species to extinction
14. Predation
List 2 distinguishing characteristics of each type of predation:
Characteristic 1
True
predators
Herbivores
Parasites
Parasitoids
Characteristic 2
15. Mutualism
a. Under what conditions would natural selection favor mutualism between two species?
b. True/false: In a mutualistic relationship, neither species evolves traits suited to helping the
other
c. Which of the following are mutualistic: (Lichens) (Viruses) (Coral) (Acacia trees) (African
lions)
16. Commensalism
a. True/false: In commensalism, both species benefit
17. Keystone Species
a. How could an ecologist identify a keystone species in any given ecosystem?
b. Why are sea stars and beavers considered to be keystone species in their habitats?
6.5 The composition of a community changes of time
18. What is the main difference between primary and secondary succession?
6.6 The species richness of a community is influenced by many factors
19. What happens to the level of biodiversity as
a. You move from the poles to the equator?
b. A habitat gets older?
c. A habitat gets smaller?
d. The more separated a habitat is?
WTS – Bringing Back the Black-Footed Ferret
20. Describe the role of prairie dogs in the grassland ecosystem. Why did ranchers not like them?
21. Describe the role of the black-footed ferret in the grassland ecosystem? Why did their populations
decline?
22. What kind of specie is the black-footed ferret (K or r) and how did this impact its recovery?
23. List some of the actions taken to help the ferret population recover.