population ecology Flashcards
define populaton
a group of conspecifics inhabiting the same area
define geographical range
the physical area that is inhabited by a population
define clumped distribution
small groups that are spread throughout a habitat
define spaced distribution
lone individuals spread from birthplace in search of breeding/feeding ground
define random distribution (seeds)
population scattered by other factors- wind etc
define fecundity
the highest potential output of of young by individuals
define fertility
the actual output of young when limiting factors are considered
what are the 5 reproductive phases? (B, JP, RP, PRP, D)
birth, birth phase, juvenile phase, post juvenile phase, death
what is the longest life phase?
reproductive phase
define mortality
number of deaths per population per time unit
what do survivorship curves display?
probability of an individual reaching maximum life expectancy
define type 1 survivorship curve (k strategist)
low mortality until PRP
define type 2 survivorship curve
constant linear decline
define type 3 survivorship curve (r strategist)
high probability of death in JP, remains constantly high throughout life
define the life history theorem. (life events, k or r?)
the time at which life stages occur define what kind of strategist the animal is
define closed population
one not subject to immi/emigration
define density independent growth (fecundity)
unconstrained growth of a population
define density independent factor
mortality is not affected by population density
define regulation of abundance (balance of pop)
when population increases during breeding season, dispersal and mortality balance it
define carrying capacity
stable equilibrium around which a population fluctuates
define natality
the number of young born in a given time
does population size increase linearly or logarithmically with a doubling of fecundity rates?
logarithmically
define longevity
age at death
which kind of strategists would you expect to find a higher number of individuals in PRP?
k
how does the 50:50 birth sex ratio fluctuate as time goes on
more females will prevail due to male-male violence
define ‘driven’ extinction. refer to environmental changes. why can a population not recover from it
a change in environment causes a decrease in pop size. too low to initiate a boom and k capacity decreases
define ‘by chance’ extinction. why is it only prevalent in smaller pop sizes?
dependent on few individuals, things like simply not finding a mate can cause extinction
define ‘genetic malfunction’ extinction. why does it occur mainly in small populations?
inbreeding occurs, genetic fitnesses decreases and diseases become prevalent
define the hierarchical approach to population control- refer to levels of cause
pop size is determined by more than one causal factor which operates on more than one level
what factors act on the landscape level of hierarchical causation? natural and anthropogenic
agriculture
succession
climate change
what factors act on an individual level of hierarchical causation?
rates of feeding
presence of predators
dispersal
define a source in the context of source-sink dynamics
an ideal environment that supports high fertility levels- birth rate higher than mortality
define a sink in the context of source-sink dynamics
the less ideal area into which young will disperse- birth rate lower than mortality
define metapopulation- refer to subpopulations
made up of many subpopulations, some acting as sources and some acting as sinks
what % of source can sustain what % of sink
10%:90%
what is the edge effect of small national reserves?
only species found at the edge of normal wild environments will be found in small national park due to more of it being nearer the edge
define demographic uncertainty as a factor causing extinction
random events in a population such as a whole generation of males being born
define environmental uncertainty as a factor causing extinction
weather causing drought
predator abundance
define natural catastrophes as a factor causing extinction
short and devastating events like hurricanes
define genetic uncertainty as a factor causing extinction
chance mutations occurring like susceptibility to a disease- usually only possible in small populations
what are the 3 categories of threat to animals?
vulnerable
endangered
critical
define extinction vortex
when multiple factors play into the extinction of a specie
what is overshoot in the context of carrying capacity?
when a population produces more offspring than the ecosystem can provide
what is die-off in the context of carrying capacity?
population decreases rapidly and falls below the k line
what is oscillation in terms of carrying capacity?
when the population moves close to the k line- either above or below
