Ecology Exam #2 Review

population

a group of interbreeding individuals of the same species occupying a particular space at the same time

density

the number of individuals per unit area

growth rate

= (B + I) – (D + E)

immigration

an animal establishes a home in a habitat because it has resources it can utilize or because the habitat is ideal for them; and animal enters an area

emigration

an animal leaves its home because the habitat is no longer ideal for them and they need to find a more suitable environment

size

the total number of individuals in the population

age structure

the number of individuals in each age group

distribution pattern

how individuals are distributed in space

• random

• clustered (clumped)

• regular (uniform)

modules

clones (groups of ramets)

genet

derived from individual zygote; difficult to age

ramets

disconnect over time; each asexually originating part of the genet

crude

___________ density ecompasses all land

ecological

_____________ density ecompasses the land that can actually be colonized by the organism

true

(true or false) population density tends to be greater for smaller organisms

density dependent

those factors limiting population growth which express themselves as a function of population size (disease, predation, competition)

density independent

those factors limiting population growth which are independent of population size (fire, earthquake, habitat fragmentation)

range

The sum of the tolerance limits for each environmental factor determines the ________ of habitats that a species can grow in.

niche

the multidimensional description of species with all aspects of its biotic and abiotic environmental requirements

range

the geographic extent over which a population exists

subpopulation

a local population of a species

metapopulation

a collection of local subpopulations

fundamental niche

a physical condtion under which a species might live

realized niche

a condition in which we actually see an organism live

random

a type of distribution pattern in which individuals have an equal probability of occuring anywhere in an area; they have neutral interactions

regular

a type of distribution pattern in which individuals are uniformly spaced through the environment; antagonistic interactions and compete for resources

clumped

a type of distribution pattern in which individuals live in areas of high local abundance, which are separated by areas of low abundance; individuals are attracted to a common resource

variance

mean used to indicate distribution type

• clumped/clustered - variance > mean

• random - variance = mean

• regular/uniform - variance < mean

regular

variance < mean

clumped

variance > mean

random

variance = mean

population size

the following equation measures ___________ _____

• M/N = m/n

• M: number of marked individuals (=size of the first sampling)

• m: number of marked individuals recaptured in a second sample

• N: estimate of population size

• n: total number of individuals captured in a second sample (=size of the second sample)

correction factor

Since mark-recapture assumptions are not always met, there is bias in estimates… this requires a __________ ______.

correction factor

the equation that measures ________ _______ is:

• M/N = (m+1)/(n+1)

mark-recapture technique

• Animals are captured and marked/photographed

• animals are released

• subsequent samples are taken

• number originally seen (marked) are noted

• equation is used to estimate population size

false

(true or false) all individuals in a population do not have an equal and independent chance of being captured (mark-recapture assumption)

true

(true or false) immigration, emigration, births and deaths should NOT significantly alter the proportion of marked and unmarked individuals in the population (mark-recapture assumption)

true

(true or false) marked animals behave in the same way, have an equal chance of being captured, and are not subject to more/less mortality than unmarked individuals (mark-recapture assumption)

false

(true or false) marked animals do not distribute themselves randomly among unmarked animals (mark-recapture assumption)

true

(true or false) animals that are marked will retain their marks (mark-recapture assumption)

100

approximately ______ (number) species go extinct each day

deterministic extinction

change occurs within an environment and organisms cannot escape

stochastic extinction

random fluctuations in population size or environment severely reduce population size; a process with random elements and thus not predictable with complete accuracy

generalist

an organism with a broad habitat tolerance

specialist

an organism with a narrow habitat tolerance

population status

______________ ________ can be interpreted through geographic range, habitat tolerance, and local population size

passenger pigeon

The __________ _________ had numbers in the billions, a notoriously narrow habitat tolerance, was common to the Eastern US, and was made extinct within 9 years.

immigration

movement into an area, increases population

emigration

movement out of an area, decreases population

population equation

N(t+1) = Nt + B + I – D - E (note that italics should be subscripts)

• N(t+1) : population density at time t+1

• Nt : population density at time t

• B: births

• I: immigration

• D: death

• E: emigration

food

Numbers of kestrels and owls seeem to closely track vole populations. This is an example of ______ induced dispersal.

climate

Following glaciation, North American trees dispersed north. This is an example of ________ induced dispersal.

adaptations

Many invertebrates that use dispersal by drift in streams employ __________ to resist downstream displacement.

Examples:

• streamline body

• sticky secretions

• ballast and retreats

• burrowing

• oviposition behavior

metapopulations

__________________ arise through dispersal of individuals among subpopulations

cohort life table

indentifies individuals born at the same time and keep records from birth

static life table

records the age at death of individuals

age distribution

calculates the difference in proportion of individuals in each age class; assumes difference from mortality

life table

analyzing a _________ ________ provides a means to study probabilities of survival, ages most vulnerable, and population growth

cohort

a group of individuals born at the same time

natality

birth of new individuals = birth rate

physiological natality

maximum possible under ideal conditions, biological limit

realized natality

the actual rate of births

crude birth rate

#1000/time (in terms of births)

specific birth rate

# of births for specific age group of females

crude death rate

# dying/1000/time

probability of dying

# dying / # beginning

probability of survival

# survival / # beginning

life expectancy

the average number of years a newborn is expected to live

true

(true or false) assessing tooth wear, plumage changes, growth rings in teeth, horns, otoliths, & shells, DBH of tees and shrubs, and annual rings on trees and shrubs are all ways of measuring the age of individuals

type I

the top line is an example of ________ ___ survivorship; this is consistent with high juvenile survival and th emost mortality occurs among older individuals

type II

the middle line is an example of ________ ____ survivorship; organisms with this survivorship die at equal rates regardless of age

type III

the bottom line is an example of _______ ____ survivorship; high juvenile mortality rate, but much lower death rates later in life

stable

_________ age distribution is when the ratio of each age group is approximately the same

stationary

_____________ age distribution is when a population is not growing

x

age class (in life table analysis)

nx

number of surviving to age class x (life table analysis); “x” should be a subscript

Ix

survivorship, proportion surviving to age class x (life table analysis); “x” should be subscript

bx

also mx, birth rate, the average number of offspring produced per individual in age x (life table analysis); “x” should be subscript

dx

number of dying within each age class x (life table analysis); “x” should be subscript

qx

age specific mortality rate (life table analysis), percent of dying between age x and age x+1; “x” should be subscript

sx

proportion surviving to the next age class (life table analysis); “x” should be subscript

Lx

average number alive during the interval (life table analysis); “x” should be subscript

Tx

the total years all individuals live into future (life table analysis); “x” should be subscript

ex

life expectancy for each age class (life table analysis); “x” should be subscript

R0

net reproductive rate (life table analysis); the average lifetime number of female offspring produced by an individual female in population in her lifetime; “0” should be subscript

generation time

average time from fertilized egg to fertilized egg/seed to seed

r

per capita rate of increase or intrinsic rate of increase; equals per capita birthrate minus per capita death rate (b-d) or (lnR0)/T for life table

geometric rate of increase

λ; the ratio of the population size at two points in time

stable population

for net reproductive rate, values = 1.0, indicates a __________ ____________

growing population

for net reproductive rate, values > 1.0, indicate a __________ ____________

decreasing population

for net reproductive rate, values < 1.0, indicates a __________ ____________

stable

if r = (b-d) = 0, population is _____________

increasing

if r = (b-d) > 0, population is ____________

decreasing

if r = (b-d) < 0, population is ________________

per capita rate of increase

( r ) when reproduction is continuous and generations overlap

Where:

• r<0 : population decreases

• r=0 : population stable

• r>0 : population increases

geometric increase

(λ) when reproduction is discontinuous and generations do not overlap

Where:

• λ < 1 : population decreases

• λ = 1 : population stable

• λ > 1 : population increases

generation time

(Σ x lxmx)/Ro

geometric

_____________ population growth; generations do not overlap and the ratio of number of individuals at time (t+1) to the number of individuals at time (t) is always that same; abundant resources

exponential

_____________ population growth; j-shaped pattern is produced, very rapid growth (unrestricted growth)

logistic

____________ population growth; produces sigmoidal or s-shaped growth (restricted growth)

carrying capacity

K, the number of individuals of a population the environment can support