Topic 11: Population Growth

Question 1

Population size is influenced by: (4)

Answer 1

death, birth, immigration, emigration

Question 2

dN/dt =

Answer 2

N/T = B-D

Question 3

b =

Answer 3

per capita birth rate

B/N

Question 4

d =

Answer 4

per capita death rate

D/N

Question 5

r =

Answer 5

per capita growth rate

b-d = (B-D)/N

Question 6

Rmax

Answer 6

intrinsic rate of increase
- always positive and constant

Question 7

Formula for exponential growth

Answer 7

Nt = N0(1+rmax)^t

Question 8

________ rmax = more reproduction (r-selected)

Answer 8

increase

Question 9

exponential growth curves ____ reach maxima

Answer 9

never

Question 10

What limits population growth? (5)

Answer 10

• temperature (affects metabolism and E produced)
• precipitation
• predators
• disease
• food availability

Question 11

When N > K, r = _________ and population _____ back down to K

Answer 11

negative; shrinks

Question 12

Carrying Capacity (K)

Answer 12

r changes as N approaches K
- maximum population size of an organism that an ecosystem can support indefinitely

Question 13

growth rate _______ as N approaches K

Answer 13

decreases

Question 14

the growth rate is ____ than ideal when r is less than rmax

Answer 14

less

Question 15

How does r change with N in logistic population growth? (graph slope?)

Answer 15

decreasing slope

Question 16

When N<K, r ___ 0

Answer 16

> , greater than

Question 17

When N>K, r ____ 0

Answer 17

<, less than (negative)

Question 18

When N=K, r ___ 0

Answer 18

=, equals

Question 19

What is the inflection point on a logistic N v. Time curve?

Answer 19

K/2

Question 20

Equation for logistic growth:

Answer 20

Nt+1 = Nt(1+rt)

Question 21

Population growth is influenced by:

Answer 21

density-dependent and independent factors

Question 22

Density-dependent factors:

Answer 22

biotic:
- food availability
- shelter
- mates
- predation
- disease

Question 23

density-dependent factors have an ________ effect as N increases

Answer 23

increasing

Question 24

Density-independent factors:

Answer 24

abiotic:
- temperature
- precipitation
- light
- disturbance (ie. fire, flood etc.)

Question 25

density-dependent factors ______ have an effect on N

Answer 25

always

Question 26

How do life history strategies influence population growth of r-selected species?

Answer 26

• live in environments with high disturbance
• early maturing
• stay @ bottom of the curve
• low survivorship
• high fecundity
• semelparious
• fast growth
• low population

Question 27

How do life history strategies influence population growth of K-selected species?

Answer 27

• live in environments with low disturbance
• fluctuate near K
• stay at top of curve
• high survivorship
• lower/more stable growth
• iteroparous
• low fecundity
• can survive extremes
• large population-

Question 28

crowding (density dependent factor) influenceS:

Answer 28

growth rate, adult size, and survival rate

Question 29

Body mass vs. time graph

Answer 29

increasing growth rate

Question 30

mass per plant vs. density graph

Answer 30

decreasing

Question 31

% survival vs. age graph

Answer 31

decreasing