Ecology Basics Flashcards
population size
number of individuals making up its gene pool
dependent on births, immigration, deaths, and emigration
population density
number of individuals per unit of area or volume
population distribution
the general pattern in which the population members are dispersed through its habitat
clumped = most common
uniformly dispersed = rare
randomly dispersed
age structure
defines the relative proportions of individuals of each age
pre-reproductive, reproductive, post-reproductive
population growth
G=rN (r = rate of increase, n=# of individuals)
exponential growth
if birth and death rates of a population remain constant they can be combined into one variable
r = net reproduction per individual per unit time (rate of increase)
ecology
how organisms interact with each other & environment
environment
biotic (organisms) abiotic (physical factors)
ecological organization
population, community, ecosystem, biosphere
ecology of individual organisms
physiological ecology, temperature and water balance, light and biological cycles, physiological ecology and conservation
ever-increasing rates and shorter doubling times
as long as per capita birth rates remain even slightly above per capita death rates, a population with grow exponentially
biotic potential
the max. rate of increase under ideal conditions
limiting factor
any resource that is in short supply, e.g. food, minerals, light, living space, refuge from predators, etc
carrying capacity
max. number of individuals of a species/population a given environment can sustain
(Because of limiting factors populations rarely exhibit J shaped growth curves )
logistic growth
Early on populations will exhibit very rapid growth but as they near the carrying capacity they will level off (S shaped curve)
growth is affected by the density of individuals.
