Chapter 11

Question 1

When experimental plants were grown at high densities…

Answer 1

the proportion of resources allocated to leaf production increased

Question 2

Which of the following factors is most likely to be density-independent regulator of population growth?

Answer 2

drought

Question 3

Self-thinning occurs…

Answer 3

at high population densities

Question 4

In a wolf pack, the beta male is

Answer 4

closely related to the alpha male

Question 5

Which of the following is a density-independent factor?
a. weather event
b. shelter availability
c. availability of mates
d. food availability

Answer 5

a. weather event

Question 6

The carrying capacity is the population size at which dN/dt is…

Answer 6

equal to 0

Question 7

Which of the following is negatively correlated with territory size?
a. number of mates
b. bird density
c. bird size
d. number of offspring

Answer 7

b. bird density

Question 8

When individuals in a small population have difficulty finding a mate, this is referred to as…

Answer 8

the Allee effect

Question 9

The inidivudlas that disperse as a response to high population density are generally

Answer 9

the younger members of the population

Question 10

The model dN/dt = (b-d)N makes 2 assumptions:

Answer 10

there is unlimited essential resources
there is a constant environment.

Question 11

What is carrying capacity, and what is its variable?

Answer 11

When birth rate = death rate. Represented by K

Question 12

What does K/2 represent

Answer 12

1/2 of the carrying capacity. This is where the fastest rate of growth is occurring.

Question 13

What formula takes into account carrying capacity?

Answer 13

dN/dt = rN(1-N/K)

Question 14

What do the variables represent for the carrying capacity formula?

Answer 14

dN - change in population
dt - change in time
r - growth rate
N - population size
K - carrying capacity

Question 15

Define density-dependent mortality

Answer 15

Rate of mortality increases as population density increases.

Question 16

Why does mortality increase as population increase? (3)

Answer 16

• reduced resource availability
  -changes in predation pattern
  -spread of disease and parasites

Question 17

Define density-dependent fecundity

Answer 17

Rate of fecundity decreasing as population density decreases.
*Doesn’t have to kill you to reduce fecundity.

Question 18

Define competition

Answer 18

When individuals use a common limited resource. Not enough of a resource for all individuals

Question 19

Define intraspecific

Answer 19

Competition among individuals of the same species. Typically happens due to the same species having very similar resource requirements.

Question 20

What does competition for resources at high population densities cause?

Answer 20

Can suppress individual growth and reduce survival.

Question 21

What happens to growth rate and phenotypic plasticity in high-density populations?

Answer 21

Growth rate decreases.
Competition-induced phenotypic plasticity occurs.

Question 22

Define phenotypic plasticity

Answer 22

The ability of organisms with a given genotype to develop varying phenotypes under fluctuating environmental conditions.

Question 23

Define self-thinning and what it is caused by.

Answer 23

Individuals of a species dying off and leaving more room for the remaining individuals to grow. Caused by the combined effect of a density-dependent mortality and growth within a population. As density declines, growth of remaining individuals increases.

Question 24

How do plants self-thin? animals?

Answer 24

Plants do this by outcompeting and causing others to die (think if a plant grows taller quicker it will block sunlight for other plants)
Animals do this through dispersal.

Question 25

How does competition reduce fecundity?

Answer 25

A greater population density results in a higher age at first reproductive event. Higher age is a result of limited resources causing an organism to spend longer times in the growth & development phase.

Question 26

What does stress cause? (5)

Answer 26

-Suppression of growth
-Curtails reproduction / delays sexual activity
- Makes individual more vulnerable to disease
-Increases fetal mortality
-Reduced milk production resulting in stunted growth of their young

Question 27

How does a high density affect dispersal?

Answer 27

Lack of resources can cause individuals to disperse or cause sub-adults to be driven out of the area by adult aggression.

Question 28

Define Social Behavior

Answer 28

The degree to which individuals of the same species tolerate each other.

Question 29

What does social behavior limit?

Answer 29

Limits the number of animals living in the same habitat with a common food supply

Question 30

How are social groups typically organized? What are it’s 2 opposing forces?

Answer 30

Based on aggression, intolerance, and domination of one individual by another. Made up of 2 opposing forces:
-Mutual attraction of individuals
-Need for individual space

Question 31

Define Home Range

Answer 31

Area that an animal normally uses over the course of a year

Question 32

What causes the size of a home range to vary?

Answer 32

-food availability
-mode of food gathering
-body size
-metabolic needs