Population Growth pt. 2

Question 1

Population growth can be reduced TEMPORARILY due to what?

Answer 1

abiotic (environmental) conditions

Question 2

Density independent environmental factors

Answer 2

limit the growth rate of a population, regardless of the population’s size

Question 3

What is this an example of:

The lethality of a natural disaster in a certain location is completely independent of the size of an animal or plant population in that location.

Answer 3

density independent environmental factor

Question 4

Density dependent biotic factors

Answer 4

affect the growth rates of large populations differently than smaller populations (usually negative relationship between density and pop. growth)

Question 5

What is this an example:

As fruit fly populations grow, competition for resources increases, causing population growth to slow (fewer births and earlier deaths).

Answer 5

density dependent biotic factors

Question 6

How is the logistic growth model used?

Answer 6

in scenarios with negative density dependent growth

Question 7

According to logistic growth model:

Growth rate is exponential when____

Answer 7

Growth rate is exponential when POPULATION SIZE IS RELATIVELY LOW (low competition, low rate of disease transmission)

Question 8

According to logistic growth model:

Growth rate slows as ____

Answer 8

Growth rate slows as POPULATION SIZE GETS RELATIVELY HIGH (high competition, high rate of disease transmission)

Question 9

In populations with logistic growth, the growth rate goes to zero when…

Answer 9

when the population reaches the maximum number of individuals that can survive in a given area

Question 10

Carrying capacity, K

Answer 10

it’s the max # of individuals of a species that can be supported in a habitat, based on the # of available resources (food, space, water, etc.)

Question 11

Logistic growth equation

Answer 11

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

Question 12

In the logistic growth model equation, what does each unit stand for:

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

Answer 12

dN/dt = instantaneous growth rate
r = intrinsic growth rate, per individual (r = b-d)
N = population size
K = carrying capacity

Question 13

Instantaneous growth rate (dN/dt) decreases as _ approaches _.

Answer 13

Instantaneous growth rate (dN/dt) decreases as N approaches K.

Question 14

When population size is small the logistic growth equations ….

Answer 14

acts like the exponential growth equation

Question 15

When population size is at the carrying capacity ….

Answer 15

the growth rate becomes 0

Question 16

How do you visualize the patterns of the likelihood of survival for juvenile to death of adult?

Answer 16

survivorship curves

Question 17

Type 1 survivorship curve

Answer 17

species with low mortality rate early in life, high mortality rate later in life (K-selected species)

Question 18

Type 2 survivorship curve

Answer 18

species with constant mortality rate throughout life

Question 19

Type 3 survivorship curve

Answer 19

species with high mortality rate early in life, low mortality rate later in life (r-selected species)

Question 20

What are life tables

Answer 20

they organize data on the birth rates, death rates, and fecundity for each age class in a population

allow ecologists to understand how each age class contributes to population growth, using actual collected data rather than model estimates

Question 21

T or F

Data for males AND females are used in life tables.

Answer 21

FALSE

only data for females

males no because paternity is difficult to figure out

Question 22

T or F

Life tables determine population growth between No and Nt. They tend to be more accurate than geometric growth models, as fewer assumptions need to be made.

Answer 22

TRUE