Population Ecology Flashcards
hyper dispersion
equidistant from eachother
-> fish schools, seabirds
random dispersion
individuals are distributed without respect to others
-> grazing wildebeest, beach clams, forest spiders
clumped dispersion
most common, clumped areas
what are the two types of clumped dispersion?
course grained and fine grained
what is fine grained?
clumps separated by short distances
what is coarse grained
clumps separated by large areas
what are the major reasons for animals to exhibit clumped distributions?
resources are clumped, behavior that facilitates grouping
what differences in microhabitats might influence plant clumping patterns?
soil moisture, nutrients, sunlight
what might influence an animals behavior to facilitate grouping?
social context, family groups, predator defense, shelter
what is dispersal?
movement of individuals away from the immediate environment of the place of birth
what is migration?
mass directional movement of large numbers of individuals from one place to the next
dispersal leads to….
gene flow
dispersal is _____ in the majority of species
widespread
why do whales travel to hawaii in the winter to have their young?
young whales are susceptible to cold
why do salmon leave the coastlines for the open ocean if there are fewer sources?
predator avoidance
Monarch butterflies: how many generations does the butterfly migration take?
4
Monarch butterflies: how many generations does the south-north route take?
3
monarch butterflies: how many generations does the north-south route take?
1
what is density
number of individuals per unit/volume
what are three ways to obtain absolute density?
- total counts
- quadrat sampling
- mark, release, recapture
how do you typically obtain total counts of a population?
take a photo and count from there
in the peterson/lincoln index for mark, release, recapture, what is N?
populatin size
in the Peterson/lincoln index for mark,release and recapture, what is M?
number of marked individuals in the population
in the Peterson/lincoln index for mark,release and recapture, what is n?
number of individuals in the sample
in the Peterson/lincoln index for mark,release and recapture, what is m?
marked number of individuals in the sample
what is the equation for the peterson/lincoln index for mark, release, recapture?
M/N = m/n
assumptions for reliable population estimates in mark-recapture studes
1) population is constant
- no immigration, no emmigration, no births, no deaths
- this is only really possible in short time frame
2) marked individuals have the same chance of getting caught as unmarked individuals
3) marked individual`s do not incur greater mortality
- stress related mortality
- mark-associated mortality
4) marked individuals don’t lose their marks
the population (N) is largely constant over the duration of the mark-recapture studies means that there cannot be any…
- immigration, emigratoin, births, deaths
what is the assumption of equal catchability?
marked individuals have the same chance of getting caught as unmarked individuals
what type of stress related mortality is common in released fish?
osmotic shock
what is the advantage of flipper bands on penguins? why don’t we use them any more?
can be read from a distance, decreases wearer’s survival and breeding success
fish tags guide to seal predators: seals can….
hone in on acoustic tags routinely attached to fish -> seals find tagged fish faster
what is the significance of genetic fingerprinting?
is a non-invasive method
N(t) = ?
number of individuals in the population at time t
N (t+1) = ….?
number of individuals in that population at t +1 (1 yr or 1 generation)
time-specific life table shows
age structure at a single point in time
what are life table construction useful for?
estimating mortality rates, survival rates, survivorship curves, and average life expectancy
what are the two types of life tables?
age specific (cohort) and time specific
cohort analysis follows a group of individuals from the same ____ from _____ to _____
age-class, birth, death
cohort analysis is most useful for
short lived species
time speciic life table requires ______ of a population
age distribution
time specific life table is usually used with _______
long lived animals
time specific life table is a
static life table
what are some new ways to age organisms?
telomeres on chromosomes
survivorship is calculated from _____
the original group
mortality is calculated from the
previous group
survivorship is calculated by
I(x) = N(tx)/N(t)
what is I(x)?
survivorship index for specific age class
what is N(tx)?
number of individuals in a specific age class in a population at time t
mortality is calculated by
q(tx) = [N(tx) - N(tx+1)] / (N(tx)
what us q(tx)?
mortality rate of a specific age class at time t
what does N(Tx) in the mortality rate equation refer to?
the number of individuals entering an age class
what is N(tx+1) in the mortality rate equation?
the number of individuals leaving an age class (one older than the target age class)
life expectancy
expected number of additional years of life remaining at any specific age
what is e(x)
life expectancy
how many main types of survivorship curves are there?
3
mammals tend to have a _______ survivorship curve
type 1
many birds, small mammals, lizards and turtles tend to have a _____ survivorship curve
type 2
many invertebrates, fish, amphibians and plants tend to have a ______ survivorship curve
type 3
what parameters do we need to estimate future generations?
births, deaths, immigration, emigration
B=?
number of offspring/seeds produced (births)
what is fecundity?
an ecological concept which is the number of offspring/seeds produced
what is fertility?
physiological concept that indicates a females ability to produce offspring/seeds per unit of time
D = ?
number of individuals that die per unit period of time (deaths)
I = ?
movement of individuals into population from other regions (immigration)
E = ?
movement of individuals out of an area (emigration)
what are the 4 primary population parameters? (PPP)
b, d, i, e
what equation is used to estimate numbers of a population in the future using 4PPP and current population estimate?
N (t+1) = N(t) + b + i - d -e
age-specific fecundity rate (ASFR)
average number of male and female offspring produced per human female for each age group
total fecundity rate (TFR)
average number of male and female offspring produced per female over her lifetime
T/F: sex ratio is irrelevant when predicting population growth
false, sex ratio is crucial information
can TFR predict whether a population is growing, decreasing, or stable?
no
life tables are often only calculated for _____
females
what is m(x)?
average number of daughters produced by each age class of females
what is the equation for reproductive rate?
I(x)m(x)
what is i(x)m(x)?
survivorship of reproductive females in any age group * number of daughters produced by each age class of females
what is R(0)?
the average number of breeding daughters that will be produced by each breeding female in the population in her lifetime
net reproductive rate (NRR) is represented by what?
R(0)
if R(0) is < 1,
the population is decreasing
if R(0) is > 1,
the population is increasing
if R(0) is = 1
the population is stationary
if R(0) = 1.33 for a population of 100 female lions….
population will grow to 133 females per generation
if a species breeds once and dies (_____), population size after a single reproductive season (_____) is predicted by what equation?
semelparous, pulsed reproduction, Nt+1=R(0)N(t)
if a population grows without constraints it is called
geometric growth
if net productive rate is unknown….
can use lambda
λ = ______
or ______
or ______
geometric rate of increase, finite multiplication rate, finite rate of increase
what is the equation to find λ?
λ = N(t+1)/N(t)
semelparous species have…
non-overlapping discrete pulsed generations
what equation is useful for estimating the geometric growth of the population in the future?
N(t)= N(0)λ^t
iteroparous species…
population growth after reproduction is predicted by exponential growth equations
what equation is used for exponential growth equations?
dN/dt = rN
what is dN, dt, and dN/dt?
- rate of change in numbers, rate of change in time, rate of population increase
what is r?
per capita rate of population growth (intrinsic rate of natural increase)
how can we find r?
r = birth rate (b) - death rate (d)
what is the equation to determine the actual population (N) at some point into the future (t) for a population with overlapping generations?
N(t) = N(0)e^(rt)
what is e
base of the natural log, = 2.171828
if r is negative, population _____
if r is 0, population _____
if r is positive, population _____
declines
is stable
increases
an alternative method of estimating r is to use the equation
r = log(e)R(0)/T(c)
the equation r = log(e)R(0)/T(c) ignores ______ and _____
immigration, emigration
what is T(c)?
generation time
what are two reasons populations cannot grow indefinitely?
finite resources run out, renewable resources are limited
what is k?
carrying capacity, total number of individuals of a species that can be sustained in a habitat in the long term
k is often…
estimated as the average population numbers of species observed across multiple years
k is estimated in…
hindsight
what happens when there is exponential growth of population past K
if it goes past K it cannot continue much longer
what is N/K?
environmental resistance
what is the equation for logistic growth?
dN/dt = rN[(K-N)/K]
what determines the carrying capacity (K)?
most limiting resource
what is environmental resistance
sum of environmental factors (drought, mineral deficiencies, competition) restricts the biotic potential (ability of population to increase) stabilizes at K…
–> GOOD
name the variations in logistic growth graphs… (carrying capacity)
- Ideal logistic (smooth response)
- Damped oscillations
- Stable limit cycle
- Chaotic
this is an example of….
ideal logistic (smooth response)
this is an example of…
dampened oscillations, oscillates around carrying capacity but as the time goes on oscillations lessen
this is an example of…
stable limit cycle, oscillates around carrying capacity.. constant oscillations
this is an example of…
chaotic, overshoots carrying capacity a lot and then huge downfall… probably when reproduction is high strong density regulating population size.
K in human species
we are growing exponentially
What are intrinsic factors limiting K
population numbers (birth rate, death rate, foraging activity, over-grazing, habitat degradation, disease transmission)
What are ways of population regulation? (before population exceeds k)
- regulation by increased mortality
- regulation by decreased births
- regulation by decreased births and increased mortality
where is the K on these graphs?
where the birth and death lines intersect
what are the mechanisms for density-dependant effects when populations exceed K?
- Intraspecific competition
- delayed breeding or reduced offspring production
- territoriality
- dispersal
- parasite/disease
- predators
what is intraspecific competition
occurs when required resources such as food, space, or mates are in limited supply
what is interference competition?
individuals directly interfere with others for limited resources
interference competition example
lions excluding others from a kill
what law has to do with the differential ability to secure resources?
law of constant final yield
what are two types of intraspecific competition
interference competition and differential ability to secure resources
delayed breeding or reduced offspring production
regression
- as population increases, calf recruitment decreases
- as number of breeding pairs increase, average clutch size decreases
general mechanisms for birth rate reduction and population regulation
- increased aggressive/submissive encounters
-increased stress among sub-dominant individuals - increased stress leads to hyper activation of the HPA, alters secretion of growth and sex hormones
- leads to suppression in body growth, suppression in reproduction, suppression in immune system
- in pregnant females this leads to inflammation of kidneys, enlarged adrenal glands, uterine mortality, decreased lactation
- young born to stressed mothers: low body weight, poor survival, delayed puberty, low reproductive rate
- odour of urine from females delays puberty in juveniles during periods of high population density
increased territoriality leads to reduction of numbers of ______ which leads to ______
non-territorial individuals, reduced reproduciton
territorial defence by dominant individuals leads to _____…_____ by sub-dominant individuals
reduced access to resources
Dispersal
members of a population disperse to regulate the number of individuals
- if you put voles and predators (or just voles) in an enclosed cage (no dispersal) bad for carrying capacity
Ups and downs of wildlife population regulation by macroparasites:
_____ _____ are the main regulatory influence on the population dynamics of svalbard reindeer
gastrointestinal nematodes
Ups and downs of wildlife population regulation by macroparasites:
although parasites do not appear to have a major affect on _____ _____, they do have a significant negative impact on the _____…_____
host survival, probability of a female reindeer becoming pregnant
Ups and downs of wildlife population regulation by macroparasites:
the nematodes’ impact their hosts at the_____ level and this, in theory, is sufficient to regulate the _____…_____
individual, host population dynamics
average number of parasites for fish
2
average number of parasites for bird
8
average number of parasites for mammals
15
average number of parasites on tree
95
order from in increasing number of parasites per host:
tree fish birds mammals tree bugs wasps flies beetles moths butterflies
fish
tree bugs
beetles
flies
birds and wasps
butterflies and moths
mammals
trees
predators are
major sources of mortality in the survivorship curve for most species
_____ _____of prey allows predators to expand - this leads to _____ _____ predation on prey
increased density, proportionally greater
predators spend more time in habitats…
where prey are abundant, this leads to a reduction in population numbers of prey
meta-analysis of density-dependent population regulation:
parasites and disease are most abundant in
a) small mammals and birds
b) large mammals
c) insects
c
meta-analysis of density-dependent population regulation:
predators are most abundant in
a) small mammals and birds
b) large mammals
c) insects
c
meta-analysis of density-dependent population regulation:
mortality from limited food is most abundant in
a) small mammals and birds
b) large mammals
c) insects
b
meta-analysis of density-dependent population regulation:
mortality from limited space or overcrowding most abundant in
a) small mammals and birds
b) large mammals
c) insects
a
density independent population regulation
- reduction in ____ of the habitat
- mainly due to _____ _____
- mortality due to ______…_____
- Largely _____ of N
carrying-capacity, extrinsic factors, severe external conditions, independent
sun spots, hurricanes, drought, deforestation, lunar cycles and fires are all examples of what kind of population regulation?
density independent population regulation
predator/prey rises and falls (hare and lynx)
stress from unsuccessful pursuits by predators causes stress that reduces the reproductive rate of females hares and is transmitted to their offspring, who also suffer reduced reproductive rates. the maternal effects produced by predation risk induce time lag in the response of hare reproductive rate to density, aiding the cyclic dynamics
What else could this predation/prey rise and fall be because of
sunspots.
sunspots = reduced heat but greater solar output
also lines up with these rises and falls
how long was each rise and fall
10 years peak to peak
another reason for this predation rise/fall
9.3 year nodal half-cycle of the moon
night without darkness
moon rises before sunset and sets before sun rises
don’t understand
could affect stress, temp, cloudiness, ultrab radiation, food plant quality… causes prey to decrease
sunspots are localized zones of _____ _____ output signify overall _____ _____ output
reduced heat, greater solar
sunspots signify _____ solar energy, which _____ length of winters, meaning hares can potentially have a _____ _____
increase, decrease, second litter
what is cathermal
active ay any time
what is crepuscular
active at dawn and dusk, not in full light or darkness
showshoe hares are…
cathermal, preditors are crepusular
