ICA 4 COMPETITION
Group Name _______________ Your name _______________
PART 1
1. What is facilitation?
Why would a species AID another species? Is it costly?
2. Define competition.
What defines a superior competitor?
3. What’s the difference between exploitation __________________________________
vs. interference______________________________________ competition?
Intra-_______________________ vs. inter-________________specific competition?
4. Allelopathy: allelo= __________ pathy _____________
How does it work? _____________________________________________________
5. Plants compete for what resources? ________________________________________
Animals compete for what resources? ______________________________________
6. Does a resource have to be limited for competition to arise? Explain _____________
____________________________________________________________________
What’s a renewable resource? ____________________________e.g _____________
What’s a non-renewable resource? __________________________e.g. ___________
7. What is Liebig’s Law of the Minimum?______________________________________
_____________________________________________________________________
How does it affect population growth?______________________________________
Fig. A.Why is it considered ‘simplistic’?
__________________________________________
Fig. B.What is meant by synergism?
_____________________________________________
8. Figure C. What is the Law of Constant Yield?_______________________________
____________________________________________________________________
9. How does intraspecific competition relate to density-dependent regulation of
population growth?_____________________________________________________
What are 4 negative density-dependent growth responses? _____________________
____________________ _______________________ _______________________
10. Describe results for:
Fig. 1 A______________________________________________________________
B_______________________________________________________________
Fig. 2 _______________________________________________________________
Fig. 3 _______________________________________________________________
Fig. 4 _______________________________________________________________
Fig. 5._______________________________________________________________
What does the dark circle represent on the two lines? ______________________
What does the dark circle on the X-axis represent? ________________________
11. What is the formula for logistic growth? ____________________________________
Which component represents intraspecific competition? ________________
What is the consequence for population growth? ____________________________
Express the effect of population size on r: __________________________________
At what value of r does N = K? ___________________
12. What is the effect of interspecific competition on r? _________ on K ____________
Fig. 6. How much is K of sp 1 reduced by one individual of competing sp 2? _____
…by all individuals? ___________
13. How is interspecific competition added to the logistic equation? ________________
How does its addition affect dN/dt? _______________________________________
What is the competition coefficient 1,2 ____________________________________
What is the competition coefficient 1,2 ______________________________________________________
Figure 7. What is the value of 1,2? ___________________
PART 2
1. Operationally, what is a niche?____________________________________________
What is meant by a hypervolume of niche space? _____________________________
2. What is niche breadth in relation to a resource axis?___________________________
What is niche overlap?___________________________________________________
How is niche breadth affected by intraspecific competition? _____________________
interspecific competition? _____________________________
What is a consequence for the community of a reduction in niche breadth due to
competition? ________________________________________________________
What is the difference between fundamental _________________________________
realized___________________________niche? Which is smaller? ______________
3. Figure 8. B. What do the different contour lines represent? __________ Under what
conditions is the bird most abundant? ________________________Does Figure 8B
show the fundamental or realized niche of the bird? ___________________
Figure 8 A. Are fundamental or realized niches shown? _________________What
will be the realized niche of species A? _____On what does it depend? ___________
4. What is meant by “the ghost of competition past”? ____________________________
_____________________________________________________________________
How does the ghost make it hard to claim that competition explains the
present-day niche space of a species?_______________________________________
5. What types of evidence are used to deduce that interspecific competition has occurred
in the past? Explain each.
A.
B.
C.
D.
E.
6. Fig. 9.What happens to niche overlap when closely related species co-occur? _______
Fig. 10. What happens to habitat use when closely related species co-occur? ________
How would you test the hypothesis that 2 species don’t use the same part of the
habitat because of competition? _______________________________________
Fig. 11. How do traits of two species compare when they co-occur vs. when they do
not? ______________________________________________________________
Fig. 12. What is the Competitive Exclusion Hypothesis?________________________
__________________________________________________________________
Fig. 12A. Under what conditions can two species coexist? ______________________
_________________________________________________________________
Fig. 13. What is the main conclusion of this experiment? ______________________
_________________________________________________________________
Fig. 14. Krill, shrimp-like organisms, are fed on by all large marine animals. What
does the killing of whales do to seal and penguin populations? _______________
How does this illustrate ‘competitive release’? ___________________________
_________________________________________________________________
7. What is meant by ‘apparent competition’? __________________________________
__________________________________________________________________
Figure 15. Starfish feed on species of herbivores (barnacles, mussels, limpets, and
chitons). Does its presence control diversity of these herbivores?
If…_________________________________________________________________
then________________________________________________________________
In an experiment in which starfish were removed, the number of herbivore species
rapidly declined from 15 to eight.
How does the result relate to competition? __________________________________
____________________________________________________________________
What is a keystone predator? ____________________________________________
____________________________________________________________________
8. Figure 16. Describe the main pattern in A. __________________________________
_____________________________________________________________________
in B. _________________________________________________________________
Which species of amphibian is most competitive in the absence of the newt? _______
in the presence of 8 newts per pond? __________What is the ‘take-home’ message
about predators and competition? __________________________________________
HOMEWORK DUE THURSDAY: PROBLEMS 4 AND 5 AT END OF PPT FOR
COMPETITION; USE WORKSHEET ON WEBSITE = ICA 5 COMPETITION
PROBLEMS.