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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
Ro
= Net Reproductive rate Average number of seeds/offspring produced by an individual in a population during its lifetime. Ro=Σ lx bx
26
If R0 = 1.0
Population is stable | Females on average produce one daughter, replacing themselves
27
If R0 > 1.0
Population is growing | Females on average produce more than one daughter;
28
If R0 < 1.0
Population is declining | Females on average produce less than one daughter;
29
Stable Age Distribution
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
Geometric Rate of Increase (Finite multiplication rate) (λ): | λ = R0 when generations
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
Generations Overlap | Population growth rate not equal to what
Population Growth Rate ≠ R0
32
Growth Rate =
(B – D) + (I – E)
33
``` Geometric Growth appropriate for _____ growth _______ generations _______ growth what symbol ```
``` Appropriate for: Discrete growth Non-overlapping generations Unlimited growth Nt = N0λt lambda ```
34
``` Exponential Growth Appropriate for populations: Growing ______ ______ generations what symbol? ```
``` Appropriate for populations: Growing continuously With overlapping generations. Unlimited Environment Nt = Noer0t r ```
35
On average, small organisms have:
Higher rates of per capita increase
36
``` Logistic Growth what symbol ____ shaped curve as resources are depleted population growth ```
``` 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
Carrying capacity (K)
Number of individuals of a population the environment can support. Finite amount of resources can only support a finite number of individuals.
38
r0 (rmax | only occurs when Thera are no
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
r | in exponential growth r=
``` 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
Populations increase decrease maximal growth at
Increase below K Decrease above K Maximal Growth at K / 2
41
Equillibrium Occur when:
b = d
42
Density-dependent factors
Disease, Resource competition, predation Most important in: Large animals Constant environments
43
Density-independent factors
Natural disasters, Environmental Conditions
44
Regulation
Control of Population size with relation to Population Size Density-Dependent Intensity influenced by Density of Organisms
45
Limitation
Control of Population Size with no relation to Population Size Density-Independent
46
Competition
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
Intraspecific competition
Competition among individuals of the same species | Members of same species usually have very similar requirements
48
Scramble competition
Resources equally available to all All individuals suffer May lead to extinction or extripation
49
Contest competition
Some claim enough resources for themselves | while denying others a share of those resources
50
Exploitation competition | Result of ____ interactions
Result of indirect interactions Individuals use resources Reduces amount available for others
51
Interference competition
Result of direct interactions | Individuals use resources and prevent others from accessing resources
52
As population density increases, Space available for each individual becomes Increased _______ interactions may cause ______
Space available for each individual becomes restricted Increased Aggressive or antagonistic interactions May cause stress
53
Stress can
``` 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
Dispersal Can Be Density Dependent
``` 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
Home range
``` 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
Territory
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
Behavioral defenses of a territory include:
``` 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
Space limitation
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
Allee effect
``` 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
Density independent factors include:
``` temperature precipitation severe storms fires floods drought These influence birth- and death rates but do not regulate population growth ```
61
When environment conditions exceed the zone of tolerance for an organism it can affect
``` 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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