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ecology exam 2 and 3 > module 9 > Flashcards

module 9 Flashcards

1
Q

Population growth describes

A

Describes how the number of individuals in a population changes over time

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2
Q

Individuals

added through leave through

A

Added through births and immigration

Leave through deaths and emigration

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3
Q

Populations may be:

open closed populations

A 
Open population 
Has immigration and emigration
Closed population 
Does not have or has a very low level of immigration & emigration 
Doesn’t influence population growth
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4
Q

Age Structure

A

Relative Proportion of a population in different Age Classes

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5
Q

Required to Understand Growth & Regulation

A

Age-Related Birth Rates

Potential Mortality

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6
Q

Age-Specific Rates
Birth and Death Rates vary with age
as age increases birth rates and death rtes

A

Birth and Death Rates vary with age

as age increases birth rates decrease death rates increase

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7
Q

Life Tables

cohort

A

Cohort or Dynamic
Follows a group of individuals throughout their lifetimes
Plants, Sessile Animals, Isolated Regions
Difficult to accomplish
Time consuming
Table may not relate to future generations
Maintain individual Records

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8
Q

Static (Time-Specific) Life Table

A

Age-specific survival & fecundity of individuals of different ages within a population at a given Time
Limited by ability to Age Individuals
Assume:
Cohort Sizes Constant
Newborn Populations of each age Class
Environmental Factors similar among all cohorts

Follow Individuals for short period
Best mortality rates
Age At Death
Age Structure at specific time

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9
Q

x

A

– age or age class

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10
Q

ax (nx)

A

Number alive at beginning of age class

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11
Q

lx –

A

Survivorship

Proportion of all individuals surviving to beginning of age class

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12
Q

dx –

A

Death Rate

Proportion of all individuals dying in age class

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13
Q

mx –

A 
Mortality Rate
Proportion of individuals that are alive at beginning of age class and that die during age class
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14
Q

sx –

A 
Survival Rate
Proportion of individuals that are alive at beginning of age class and that die during age class
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15
Q

ex –

A 
Expectation of future life
Average time span that an average individual in age class has left before death
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16
Q

bx (mx) –

A 
fecundity rate
Average number of offspring/seeds produced
May be #/-individual or #/-female
# of female offspring / adult female
Polygynous or Promiscuius
Sexually Dimorphic
# of offspring / individual
Monogomous
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17
Q

Type I

A

Majority of mortality occurs among older individuals.

Dall Sheep

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18
Q

Type II

A

Constant rate of survival throughout lifetime.

American Robins

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19
Q

Type III

A

High mortality among young, followed by high survivorship.

Sea Turtles

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20
Q

Birth Rate

A

Number of young born per female.

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21
Q

Crude birthrate

A

Number of birth during some time period (usually a year) divided by estimated population size at the beginning of the time period, multiplied by 1000

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22
Q

Fecundity Schedule

A

Tabulation of birth rates for females of different ages.

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23
Q

Age-specific birthrate (bx)

A

Sexually Dimorphic Species
Mean number of females born to each female in an age group
Female is reproductive Unit
Population increase as a function of number of females
Species with Similar Sexes
Mean number of offspring born to each individual in an age group

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24
Q

gross reproductive rate

A

Sum (Σ) across all age classes

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25
Q

Ro

A

= Net Reproductive rate
Average number of seeds/offspring produced by an individual in a population during its lifetime.
Ro=Σ lx bx

26
Q

If R0 = 1.0

A

Population is stable

Females on average produce one daughter, replacing themselves

27
Q

If R0 > 1.0

A

Population is growing

Females on average produce more than one daughter;

28
Q

If R0 < 1.0

A

Population is declining

Females on average produce less than one daughter;

29
Q

Stable Age Distribution

A

if the population is growing or declining, all age classes grow or decline at the same rate

Proportion of each age class the same in the population
Population growth becomes more predictable
30
Q

Geometric Rate of Increase (Finite multiplication rate) (λ):

λ = R0 when generations

A

λ = R0 when generations do not overlap
λ = N t+1 / Nt
N t+1 = Size of population at future time.
Nt = Size of population at some earlier time.

31
Q

Generations Overlap

Population growth rate not equal to what

A

Population Growth Rate ≠ R0

32
Q

Growth Rate =

A

(B – D) + (I – E)

33
Q 
Geometric Growth
appropriate for 
\_\_\_\_\_ growth
\_\_\_\_\_\_\_ generations
\_\_\_\_\_\_\_ growth 
what symbol
A 
Appropriate for:
Discrete growth
Non-overlapping generations
Unlimited growth
Nt = N0λt
lambda
34
Q 
Exponential Growth
Appropriate for populations:
Growing \_\_\_\_\_\_
\_\_\_\_\_\_ generations
what symbol?
A 
Appropriate for populations:
Growing continuously
With overlapping generations.
Unlimited Environment
Nt = Noer0t
r
35
Q

On average, small organisms have:

A

Higher rates of per capita increase

36
Q 
Logistic Growth
what symbol
\_\_\_\_ shaped curve
as resources are depleted 
population growth
A 
Logistic population growth. r0
Sigmoid (S-shaped) population growth curve.
As resources are depleted
Population growth rate slows 
Eventually stops
dN/dt = r0N(1-N/K)
37
Q

Carrying capacity (K)

A

Number of individuals of a population the environment can support.
Finite amount of resources can only support a finite number of individuals.

38
Q

r0 (rmax

only occurs when Thera are no

A

intrinsic rate of increase
Maximal per capita rate of increase possible in a population
Biotic potential
Rarely achieved in nature
Only occurs when no limits to growth exist

39
Q

r

in exponential growth r=

A 
instantaneous growth rate 
Per capita rate of increase at any time
Varies based on conditions
Exponential rate of increase
In exponential growth:
r = r0
40
Q

Populations
increase
decrease
maximal growth at

A

Increase below K
Decrease above K
Maximal Growth at K / 2

41
Q

Equillibrium Occur when:

A

b = d

42
Q

Density-dependent factors

A

Disease, Resource competition, predation
Most important in:
Large animals
Constant environments

43
Q

Density-independent factors

A

Natural disasters, Environmental Conditions

44
Q

Regulation

A

Control of Population size with relation to Population Size
Density-Dependent
Intensity influenced by Density of Organisms

45
Q

Limitation

A

Control of Population Size with no relation to Population Size
Density-Independent

46
Q

Competition

A

Individuals use a common resource that is limited
Not enough for all individuals who need it
No competition when:
Availability of resource is sufficient for all AND
Does not affect survival, growth, and reproduction

47
Q

Intraspecific competition

A

Competition among individuals of the same species

Members of same species usually have very similar requirements

48
Q

Scramble competition

A

Resources equally available to all
All individuals suffer
May lead to extinction or extripation

49
Q

Contest competition

A

Some claim enough resources for themselves

while denying others a share of those resources

50
Q

Exploitation competition

Result of ____ interactions

A

Result of indirect interactions
Individuals use resources
Reduces amount available for others

51
Q

Interference competition

A

Result of direct interactions

Individuals use resources and prevent others from accessing resources

52
Q

As population density increases,
Space available for each individual becomes
Increased _______ interactions
may cause ______

A

Space available for each individual becomes restricted
Increased Aggressive or antagonistic interactions
May cause stress

53
Q

Stress can

A 
Trigger hormonal changes
suppress growth
curtail reproduction
delay sexual activity
Suppress the immune system
If a pregnant female
increase fetal mortality
lead to reduced milk production or lactation
Stunting the growth and development of nursing young
54
Q

Dispersal Can Be Density Dependent

A 
Some animals disperse
Leaving the population to find a new habitat
Dispersing Individuals May: 
Die before finding suitable habitat
Find habitat
Not connected to population (Emigration)
Considered a decrease to populations
May find marginal habitat
Lower resource availability 
Decreased reproduction and Increased Mortality
55
Q

Home range

A 
Area that an animal normally uses over the course of a year
Home Range size
availability of food
mode of gathering food
body size
metabolic needs
Not defended or exclusive to
	one individual
56
Q

Territory

A

Part of the home range that an animal defends
For its exclusive use of resources
Usually smaller than home range
If an animal defends its entire home range, they are the same

57
Q

Behavioral defenses of a territory include:

A 
songs and calls
intimidation displays
Birds spread their wings and tails
Mammals bare their teeth
attacking and chasing intruders
scent marking to deter intruders
Territories of different individuals within a population are usually regularly distributed
58
Q

Space limitation

A

Number of territorial owners a habitat can support
Resource Limits from decreased Territory Size
Increases in density  smaller territory size  less resources in Territory
Energy Costs to defend Territory
More Challenges to territory

59
Q

Allee effect

A 
Density-dependent mechanisms that reduce birthrate and survival when a population is at low density
Difficulty in finding mate
pheromones carry 
	a limited distance
Pollination 
Social Breakdown
Leks
Pack Hunting
60
Q

Density independent factors include:

A 
temperature
precipitation
severe storms
fires
floods
drought
These influence birth- and death rates but do not regulate population growth
61
Q

When environment conditions exceed the zone of tolerance for an organism it can affect

A 
growth
age of maturity
reproduction
survival 
movement
If conditions are extreme
Population can go extinct

ecology exam 2 and 3 (10 decks)

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