Ecology Ch 10 Population Dynamics Cain, Bowman, Hacker. Detail

Front 1

Populations can change in size as a result of 4 processes: ___, ___, ____, & _____.
Also, summarize with equation.

Back 1

birth, death, immigration, & emigration.

Nt+1 = Nt + B - D + I - E

Nt is the pop. size at time t,
B is the # of births,
D is the # of deaths,
I is the # of immigrants,
E is the # of emigrants between time t & time t +1

Front 2

Ecologists use the term ____ _____ to refer to the ways in which populations change in abundance over time.

Back 2

population dynamics

Front 3

Patterns of Population Growth
Concept 10.1
Populations exhibit a wide range of growth patterns, including _____ growth, _____ growth, _____, & ____ ____.

Back 3

exponential
logistic
fluctuations
regular cycles

Front 4

10.1
In exponential growth, a population increases (or decreases) by a ____ proportion at each point in time.

Can be represented by either of 2 related equations,
Nt+1 =
or
dN/dt =

Back 4

constant

Nt+1 = λNt
or
dN/dt = rN
the choice of which depends on whether reproduction occurs at discrete time periods(the 1st equation) or is continuous (the 2nd equation).

Front 5

10.1
In logistic growth, the population approaches an _____

Back 5

equilibrium

Front 6

10.1
All populations ____ in size

The 3rd & most common pattern of population growth,

Back 6

fluctuate

population fluctuations

Front 7

10.1
Population fluctuations can be caused both by _______ factors and by _______ factors.

Back 7

density-independent (e.g., weather)

density-dependent (e.g., food limitation, natural enemies)

Front 8

10.1
Some species exhibit ____ ____ in which alternating periods of high and low abundance occur after nearly constant intervals of time.

Back 8

population cycles

Front 9

10.1
What factors cause numbers to fluctuate greatly over time, yet maintain a high degree of regularity?

Back 9

Possibly both
internal factors, such as hormonal or behavioral changes in response to crowding, &
external factors, such as weather, food supplies, or predators.

Front 10

Delayed Density Dependence
Concept 10.2
Delayed density dependence can cause populations to ____ in size.

Back 10

fluctuate

Front 11

10.2
The effect of population density is often _____ in time

As a result, it's common for the # of individuals born in a given time period to be influenced by the population densities or other conditions that __________________

Back 11

delayed

were present several time periods ago.

Front 12

10.2

logistic equation, modified to include a time lag, τ:
(10.1)
dN/dt =

Back 12

rN [1- (N(t-τ)/K) ]

dN/dt is the growth rate of the population at time t,
r is the (per capita) population growth rate under ideal conditions,
N is the pop. size at time t, &
K is the carrying capacity

Front 13

10.2
Eq. 10.1 is identical to logistic eq. except that within the term (1- N/K), N has been replaced by _____.
Recall the term (1- N/K) represents the effect of factors that reduce pop. growth from the exponential growth curve. Incorporating ____ within this term indicates that the pop. growth rate (dN/dt) is affected by the pop. size at time ____ in the past.

Back 13

N_(t-τ)

N_(t-τ)

t-τ

Front 14

10.2
When rτ is small, the population exhibits ________

Back 14

logistic growth.

Front 15

10.2
At intermediate values of rT, the population exhibits ________

Back 15

damped oscillations
(deviations from the carrying capacity gradually get smaller over time).
Intermediate values ~
0.368<rT<1.57

Front 16

10.2
When rT is large, the population exhibits ______

Back 16

a stable limit cycle.

large value~ rT > 1.57

Front 17

Population Extinction
Concept 10.3
The risk of extinction increases greatly in ____ ______.

Back 17

small populations

Front 18

10.3
Populations can be driven to extinction by many different factors, including predictable, or _____, changes in the environment.

Back 18

deterministic

Front 19

10.3
In a model, _____ in the population growth rate ______ the risk of extinction

Back 19

fluctuation
increases

Front 20

10.3
____ can drive small populations extinct

Back 20

Fluctuations

Front 21

10.3
____ events can drive small populations to extinction

Back 21

Chance

"chance events"
aka unpredictable events

In particular, we'll consider the role of chance genetic, demographic, and environmental events in making small populations vulnerable to extinction.

Front 22

10.3
____ factors can threaten small populations

Back 22

Genetic

Front 23

10.3
Small populations can encounter problems associated with ____ ____, and _____.

Back 23

genetic drift
inbreeding.

Front 24

10.3
____ ____ is the process by which chance events influence which ____ are passed on to the next generation.

Back 24

Genetic drift
alleles

Front 25

10.3
Genetic drift has ____ effect on large populations, but in small populations it can cause losses of ____ ____ over time.

Back 25

little
genetic variation

Front 26

10.3
Drift can reduce the genetic variability of small populations ____:

Back 26

rapidly

Front 27

10.3
Small populations vulnerable to the effects of genetic drift for 3 reasons. 1st, when drift leads to a loss of genetic variability, the ability of a pop. to ____(via natural selection) to future environmental change is ____.

Back 27

respond
limited

Front 28

10.3
Small populations vulnerable to the effects of genetic drift for 3 reasons.
2nd, genetic drift can cause ____ alleles to occur at high frequencies, often causing individuals to suffer poor _____ success.

Back 28

harmful
reproductive

Front 29

10.3
Small populations vulnerable to the effects of genetic drift for 3 reasons.

3rd, small populations show a high frequency of ______.

Back 29

inbreeding

Front 30

10.3
_______factors can threaten small populations

Back 30

Demographic

Front 31

10.3
When the pop. size is large, there is little risk of extinction from ______ _______.

Back 31

demographic stochasticity(chance events associated with whether individuals survive or reproduce).

Front 32

10.3
Demographic stochasticity one of several factors that can cause small populations to experience ____ effects.

Back 32

Allee

Front 33

10.3
Allee effects occur when the population growth rate (r or λ) _____ as the population density _____,

Allee effects can _____ small populations.

Back 33

decreases
decreases,
perhaps because individuals have difficulty finding mates at low pop. densities.

threaten

Front 34

10.3
_____ ______ refers to erratic or unpredictable changes in the environment.

Back 34

Environmental stochasticity

Front 35

Metapopulations
Concept 10.4
Many species have a metapopulation structure in which sets of ____ _____ populations are linked by ____.

Back 35

spatially isolated
dispersal.

Front 36

10.4
Metapopulations are characterized by repeated ____ & _____.

Back 36

extinctions
&
colonizations.

Front 37

10.4
Metapopulation Dynamics
Model Assumptions
a) Patches are ____
b) Large # of patches in the ____
c) Probability of colonization(Pc)____ and ____ for all patches
d) Probability of extinction (Pe) ____ and ____ for all patches
e) The intervening ____ does not affect Pc and Pe

Back 37

a) homogeneous
b) metapopulation
c) constant & equal
d) constant & equal
e) matrix

Front 38

10.4
Matrix influences:

____ between patches

patch _____

Back 38

movement
quality

Front 39

10.4
_____ _____ can cause a metapopulation to go extinct even when suitable habitat remains

Back 39

Habitat Fragmentation

Front 40

10.4
Extinction & colonizationrates often ____ among patches

Back 40

vary

Front 41

10.4
Rate of ____ determines metapopulation dynamics.

Back 41

movement

Front 42

10.4
Metapopulation processes:

1. ____ of a subpopulation
2. ____ of subpops
3. ____ of empty patches forming new subpop

Back 42

1. Persistence
2. Extinction
3. Colonization

Front 43

10.4
Metapopulations Movements

Frequent: ____ fluctuations in N damped out

Infrequent:
-subpops behave ____
-subpops not ____once extinct

Intermediate: shifting ____ of occupied & unoccupied ____

Back 43

local

independently
reestablished

mosaic
patches

Front 44

10.4

_____ _ _____ occurs when patches located far away from occupied patches are less likely to be colonized than are nearby patches.

Back 44

Isolation by distance

Front 45

10.4
This tendency for high rates of immigration to protect a pop. from extinction(by reducing problems assoc. w/small pop. size)is known as the ___ ____.

Back 45

rescue effect

Front 46

10.4
Overall, this plausible scenario suggests that extinction in the pool frog metapopulation results from deterministic events and a lack of 1)____ among older, spatially isolated ponds.
2) What are the deterministic events?

Back 46

1) dispersal

2) (pond formation & disappearance)