53: Population Ecology Flashcards
what affects the size of a population and how it changes over time
adding or removing individuals
what can be used to describe population
its boundaries and size
what is a boundary
it can be natural like an island or lake
or arbitrarily defined by an investigator
what is population ecology
explores how biotic and abiotic factors affect population, density, dispersion and demographics
what is density
the number of individuals per unit area or volume
what is dispersion
pattern of spacing among indiviudals within the boundaries of the population
what is demography
study of birth/death/migration rates
what can be used to find density
sampling techniques like the mark-recapture method
how do they use the mark-recapture method
scientists capture and tag random sample of individuals in a population and they are given back to the population then they capture a second sample and note how many they mark
what is the formula to solve for population size
x/n= s/N or N=sn/x
what is density the result of
processes that add individuals and remove individuals
what is immigration
influx of new individuals and births to increase population size
what is emigration
movement of indivduals out of a population, and deaths to decrease population size
what is the pattern of dispersion determined by
spacing among individuals within the boundaries
what factors affect the spacing of individuals in a population
environmental and social factors
what is the most common pattern of dispersion
clumped
what is a clumped pattern
- individuals aggregate in patches
- aggregate in high resource availability or favorable physical conditions
what else can influence the clumped pattern
mating behavior and group predation or defense
what is uniform dispersion
individuals spread out evenly
in uniform dispersion what do plants do
secrete chemicals that inhibit germination and growth of competing individuals
what is uniform dispersion influenced by
social interactions like territory and the defense of a bounded space against other individuals
what is random dispersion
the position of each individuals is independent of other individuals