Population Dynamics and Growth

Question 1

Population

Answer 1

group of individuals of a single species inhabiting a specific area

Question 2

Characteristics of a Population [[6]

Answer 2

1. Number of individuals
2. Density
3. Age Distribution
4. Growth rates
5. Distribution
6. Abundance

Question 3

3 Main Methods of Estimation of Patterns of Survival

Answer 3

1. Cohort Life Tables [identify individuals born at the same time/cohort and follow from age 0 until death]
2. Static Life Table [# of individuals per age class at that moment of time; snapshot]
3. Age Distribution

Question 4

Mortality vs Morbidity

Answer 4

Mortality: Death
Morbidity: Infection/sickness

Question 5

Population Survivorship curves

Answer 5

TYPE I: high mortality among older individuals
TYPE II: constant mortality rate
TYPE III: high mortality among juveniles

Question 6

Population Survivorship Curves X and Y axis

Answer 6

X-axis: Age
Y-axis: # of individuals

Question 7

Survivorship rate

Answer 7

lx = nx / n0

Question 8

Mortality

Answer 8

dx = nx - n(x+1)
DIEx

Question 9

Mortality rate

Answer 9

qx = dx / lx
“quit rate”

Question 10

Average # alive in age class

Answer 10

Lx = nx + nx+1 / 2

Question 11

What is the significance of the Age distribution of a population?[4]

Answer 11

1. History of Survival
2. History of Reproduction
3. Potential for future growth
4. Stable vs Declining populations

Question 12

_____ & _____ studied ______ [birds] to demonstrate dynamic population in a variable climate

Answer 12

Grant, Grant, Galapagos Finches

Question 13

What factors determine rate of population change?

Answer 13

1. Fecundity
2. Birth & Death rates
3. Net Reproductive rate
4. Generation time
5. Per capita rate of increase

Question 14

Fecundity

Answer 14

mx = # of female offspring of each female

Question 15

Net Reproductive Rate R0

Answer 15

R0 = Summation of [lxmx]
If R0 < 1 = declining

Question 16

Generation time T

Answer 16

Summation of (x lx mx) / R0

Question 17

Per capita rate of increase r

Answer 17

r = lnR0/T

Question 18

How does dispersal influence local population density?

Answer 18

1. Climate change
2. Prey and Predator Dispersal
3. Immigration and emigration

Question 19

Formula for continuous population growth with unlimited resources

Answer 19

dN/dt = (rmax N)
dN/dt = rate of population increase
rmax = maximum per capita rate of increase
t = number of time intervals

Question 20

Formula for size at any time of an EXPONENTIALLY GROWING POPULATION*

Answer 20

Nt = N0e^rt

Question 21

Formula for a GEOMETRIC growth curve

Answer 21

Nt = N0(lambda)^t
lambda = geometric rate of increase

Question 22

Differences between geometric growth and exponential growth

Answer 22

1. Geometric growth measures in intervals, exponential growth measures continuously
2. The appearance of geometric growth isn’t consistent unlike exponential; can appear jagged

Question 23

Logistic Population Growth & Formula

Answer 23

• resources are limiting
• sigmoidal growth curve
• carrying capacity K

dN/dT = rmax N (1 - [N/K])
so as N nears K, population growth decreases
N/K = environmental resistance to population growth

Question 24

5 assumptions of logistic population growth

Answer 24

1. Linear relationship between population density and rate of increase [inverse]
2. Instantaneous effect of density on rate of increase
3. Constancy of environment and K
4. Equal reproduction of all individuals
5. Absence of emigration and immigration

Question 25

What limits population growth?

Answer 25

1. Density-dependent factors [biotic] e.g. disease predation and parasitism –> K selection
2. Density-independent factors
   [abiotic] e.g. floods temperature extremes –> r selection

Question 26

Grant and Grant documented 5 ways that finches utilize cacti:

Answer 26

1. Open flower buds in dry season to eat pollen [FOOD]
2. Consume nectar and pollen from mature flowers [FOOD]
3. Eat seed coating [aril] [FOOD]
4. Eat seeds
5. Eat insects from rotting cactus pads

Question 27

Main source of food for cactus finches

Answer 27

opuntia helleri

Question 28

Large organisms
_____ r
_____ population variability

Answer 28

Low
Low