52 Flashcards
population ecology
study of populations in relation to the environment
dispersion
pattern of spacing among individuals within the boundaries of the population
uniform dispersion pattern may result from
direct interactions btwn individuals in the population
why do some plants exhibit uniform dispersion pattern
they secrete chemicals that inhibit the germination and growth of nearby individuals that could compete for resources
animals often exhibit uniform dispersion b/c of
antagonistic social interactions, ex territoriality
territoriality
the defense of a bounded physical space against encroachment by other individuals
__ dispersion pattern not as common in populations as __ pattern
uniform; clumped
3 factors that influence pouplation density and dispersion patterns
ecological needs of a species, environmental sturcture, interactions btwn individuals within the population
demography
study of the vital statistics of populations and how they change over time
life tables
age-specific summaries of the survival pattern of a population
cohort
group of individuals of the same age
best way to construct a life table
follow the fate of a cohort from birth until all are dead
to build the life table, we need to determine
# of individuals that die in each age group; proportion of cohort surviving from one age to the next
survivorship curve
graphic way of representing data in a life table; plot of proportion of numbers in a cohort still alive at each age
animals that exhibit type I survivorship
humans and large mammals that produce few offspring but provide them w/ good care
what type of animals exhibit type III and 3 examples
those that produce very large numbers of offspring but provide little or no care; ex long-lived plants, fishes, marine invertebrates
examples of type II organisms
belding’s ground squirrels, other rodents, various invertebrates, some lizards, some annual plants
describe bird surivorship
high morality among young (type 3), constant mortality among adults (type 2)
describe invertebrate survivorship
“stair-stepped” curve. brief periods of increased mortality during molts, followed by periods of lower mortality when exoskeleton is hard
in populations without immi/emigration, which 2 factors determine population trends
survivorship, reproductive rate
reproductive table aka
fertility schedule
reproductive table is an
age specific summary of the reproductive rates in a population
best way to construct fertility schedule
measure reproductive output of a cohort from birth til death
reproductive output for sexual species is
the produce of the proportion of females of a given age that are breeding and the number of females of a given age that are breeding and the number of female offspring of those breeding females