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34 terms

Unit 9- Population Ecology

STUDY
PLAY
ecology
study of interations between prganisms and their environment
hierarchy of interations
biosphere -> ecosystem ->community -> population -> organism
biosphere
the global system (earth)
ecosystem
all biotic and abiotic factors in a region
community
all organisms in the same region
population
all organisms of the same species in the same region
organism
single living thing
population ecology
concentrates on factors that affect population density and growth
census
individuals in a specific area are counted
mark-recapture method
individuals are captured, marked, set free then they capture some of the marked organisms and unmarked individuals
pattersn of dispersion
way individuals are spaced in a habitat
clumped pattern
individuals are aggregated into patches. cause by unequal distribution of resources
uniform pattern
individuals spread out evenly. causes from interactions from individuals
random dispersion
individuals spaced in a patternless unpredictable way
populations dynamics
factors that change a population over time
birth rate
number of births over time
death rate
number of deaths over time
life expectancy
average lifespan of individuals in a population
age structure
proportion of individuals in different age groups
growth of a population
number of births - (minus) number of deaths
growth rate
change in population size over time
expotential growth
population size multiplies by a constant factor each generation; depends on size of population; occurs in ideal regulated conditions
logistic growth model
population growth is slowed by limiting factors
carry capacity
number of indiviudals in a population that the environment can support
density dependent factors
effects intensify as population size increases
intraspecific competition
competition between individuals for resources
density independent factors
intensity is unrelated to population size
environmental factors
these factors effect the availability of resources
crash and boom
populations experience periods of rapid growth alternating with periods of decline (ex: predator-prey interactions, life cycle of individuals in the population, and variations in food supply)
exponential growth
the growth pattern in human populations (causes: inventions of tools to control or eliminate predators, advances in medical techonology, totalitarian agriculture [able to feed everyone])
non-native species
species that are not indigenous to the area
producers
if you remove this from a habitat, this reduced the primary productivity and may lead to increased CO2 levels
predators
if you remove this from a habitat, prey populations expands and exeeds carrying capacity
decomposers
if you remove this from a habitat, nutrients are not restored in soils and directly affect the producers