Mon.
Tues.
Wed.
Thurs.
Fri.
Week of
Nov. 10
Independent project analysis
Week of
Nov. 17
T lab switch?
River ecology lab – dress for weather
Week of
Nov. 24
No lab – Thanksgiving
Lab
Exam
No
lecture
Week of
Dec. 1
Independent project presentations
1
Structure of course
Environmental variability
Organisms
Ecosystems
Populations
Species interactions
Communities
Applied Ecological Issues
2
Consumer/resource interactions
1. Predation
2. Herbivory
3. Parasitism
4. Dynamics of C/R interactions
3
Why don’t herbivores drive
plants extinct?
Or
Why is the world green?
1. Plant defense
- physical
- chemical
2. Plants can hide too
3. Herbivores have predators
4
Constitutive
defense
5
Figure 17.16
Induced defense
6
Why don’t herbivores drive
plants extinct?
Or
Why is the world green?
1. Plant defense
2. Plants can hide too
3. Herbivores have predators
7
Spatial refuge
Figure 17.1
8
Index of cone production
Production of population
not individuals
Cost
9
Why don’t herbivores drive
plants extinct?
Or
Why is the world green?
1. Plant defense
2. Plants can hide too
3. Herbivores have predators
10
Predator
Herbivore
Algae
11
Consumer/resource interactions
1. Predation
2. Herbivory
3. Parasitism
4. Dynamics of C/R interactions
12
How is a parasite different from a predator?
13
Parasites are incredibly diverse
Examples?
14
15
Challenges for a parasite
16
Figure 17.14
17
pillbug = intermediate host
tapeworm in a crow
tapeworm changes
pillbug behavior
18
Consumer/resource interactions
1. Predation
2. Herbivory
3. Parasitism
4. Dynamics of C/R interactions
19
Dynamics of consumer/resource interactions
Consumers can reduce resource populations
Examples of cycles
Models of consumer/resource interactions
20
Figure 17.18
Effect on growth rate
21
22
Dynamics of consumer/resource interactions
Consumers can reduce resource populations
Examples of cycles
Models of consumer/resource interactions
23
Figure 18.4
Cause of cycle?
size of measles population
24
Figure 18.2
25
Lynx
-
+
Hare
26
Dynamics of consumer/resource interactions
Consumers can reduce resource populations
Examples of cycles
Models of consumer/resource interactions
- math helps understand mechanisms
27
For prey (R): dR/dt = rR – predation
For predators (P): dP/dt = rate at which prey
are converted to new predators – death of
predators
28
Species interactions
Introduction
Consumer/resources interactions
(predation, herbivory, parasitism)
Competition
Mutualism
29
Interspecific Competition
Introduction
Competitive exclusion
How do species coexist?
30
Competitive interactions
A
B
31
What are some resources that organisms compete for?
32
Intraspecific competition – competition between
individuals of the same species
Interspecific competition – competition between
individuals of different species
33
Two methods of competition
Interference competition
Exploitation competition
34
Figure 19.13
Exploitation
Interference
35
Intraspecific
interference
competition
Intraspecific
exploitation
competition
Interspecific
exploitation
competition
36
Competition may be asymmetric
-
A
B
37
Figure 19.11
A
B
38
Species A has a bigger effect
on B than B has on A
How would you draw this?
A
B
39
Which one of the following is not an example of
competition between species?
a. Blowflies and fleshflies breed in the same types
of carcasses, and both species experience reduced
reproduction rates when densities within carcasses
are high.
b. Sage plants produce a ring of bare ground
surrounding them.
c. Wolverines and mountain lions fight each other
for deer carcasses.
d. Spotted owls and great horned owls occupy the
same type of habitat.
40
Competition
Introduction
Competitive exclusion
How do species coexist?
41
Figure 19.6
42
Figure 19.2
43
Competitive exclusion principle: two species
that use the same limiting resource in the
same way cannot coexist
Limiting resource – a resource which is scarce
relative to the demand for it
44
Competitive exclusion is difficult to witness
outside of laboratory experiments
Why??
45
Figure 19.10
parasitoids – all use resource
same way
46
Competition
Introduction
Competitive exclusion
How do species coexist?
47
How do species coexist?
1. Resource partitioning
2. Predation on one or more species
48
How do species coexist?
1. Resource partitioning
-different species aren’t using the same
resource exactly the same way
49
Eats small to
medium seeds
Eats medium
to big seeds
50
5 warbler species
all eat insects
in spruce trees
.
.
.
.
.
51
How do species coexist?
2. Predation on one or more species
52
A
B
-
53
Consumer
+
-
A
B
-
54
Bob Paine
experiments
Mussel =
dominant
competitor
55