chpt 10,11,12 keyterms Flashcards
fundamental niche
the range of abiotic conditions under which a species can persist
realized niche
the range of abiotic and biotic conditions under which a species persists
ecological niche modeling
the process of determining the suitable habitat conditions for a species
ecological envelope
the range of ecological conditions that are predicted to be suitable for a species
geographic range
a measure of the total area covered by a population
endemic
species that live in a single often isolated location
cosmopolitan
species with very large geographic ranges that can span several continents
abundance
the total number of individuals in a population that exist within a defined area
density
in a population the number of individuals in a unit of area or volume
dispersion
the spacing of individuals with respect to one another within the geographic range of a population
clustered dispersion
a pattern of population dispersion in which individuals are aggregated in discrete groups
evenly spaced dispersion
a pattern of dispersion of a population in which each individual maintains a uniform distance between itself and its neighbors
random dispersion
a pattern of dispersion of a population in which the position of each individual is independent of the position of other individuals in the population
dispersal
the movement of individuals from one area to another
census
a count of every individual in a population
survey
counting a subset of the population
area and volume based surverys
surveys that define the boundaries of an area or a volume and then count all the individuals in the space
line transect surveys
surveys that count the number of individuals observed as one moves along a line
mark recapture surveys
a method of population estimation in which researchers capture and mark a subset of a population form an area, return it to the area, and then capture a second sample of the population after some time has passed
lifetime dispersal distance
the average distance an individual moves from where it was hatched or born to where it reproduces
dispersal limitation
a substantial barrier that prevents dispersal between suitable habitats
habitat corridors
a strip of favorable habitat located between two large patches of habitat that facilitates dispersal
ideal free distribution
when individuals distribute themselves among different habitats in a way that allows them to have the same per capita benefit
growth rate
in a population, the number of new individuals that are produced in a given amount of time minus the number of individuals that die
intrinsic growth rate (r)
the highest possible per capita growth rate for a population
exponential growth model
a model of population growth in which the population increases continuously at an exponential rate
geometric growth model
a model of population growth that compares population sizes at regular time intervals
double time
the time required for a population to double in size
density independent
factors that limit population size regardless of the populations density
density dependent
factors that affect population size in relation to the populations density
negative density dependence
when the rate of population growth decreases as population density increases
positive density dependence
when the rate of population growth increases as population density increases
also known as inverse density dependence or the Allee effect
self thinning curve
a graphical relationship that shows how decreases in population density over in the mass of each individual in the population
carrying capacity
the maximum population size that can be supported by the environment
logistic growth model
a growth model that describes slowing growth of populations at high densitites
s-shaped curve
the shape of the curve when a population is graphed over time using the logistic growth model
inflection point
the point on a sigmoidal growth curve at which the population achieves its highest growth rate
age structure
in a population the proportion of individuals that occurs in different age classes
life tables
tables that contain class specific survival and fecundity data
stable age distribution
when the age structure of a population does not change over time
net reproductive age
the total number of female offspring that we expect an average female to produce over the course of her life
generation time (T)
the average time between the birth of an individual and the birth of its offspring
overshoot
when a population grows beyond its carrying capacity
die-off
a substantial decline in density that typically goes well below the carrying capacity
population cycles
regular oscillation of population size over a long period of time
delayed density dependence
when density dependence occurs based on a population density at some time in the past
damped oscillations
a pattern of population growth in which the population size initially oscillates but the magnitude of the oscillations declines over time
stable limit cycle
a pattern of population growth in which the population size continues to exhibit large oscillations over time
deterministic model
a model that is designed to predict a result without accounting for random variation in population growth rate
stochastic models
a model that incorporates random variation in population growth rate
demographic stochasticity
variation in birth rates and death rates due to random differences among individuals
environmental stochasticity
variation in birth rates and death rates due to random changes in environmental conditions
subpopulations
when a larger population is broken up into smaller groups of conspecifics that live in isolated patches
metapopulations
the collection of subpopulations that live in isolated patches and are linked by dispersal
habitat fragmentation
the process of breaking up large habitats into a number of smaller habitats
basic metapopulation model
a model that describes a scenario in which there are patches of suitable habitat embedded within a matrix of unsuitable habitat
source-sink metapopulation model
a population model that builds on the basic metapopulation model and accounts for the fact that not all patches of suitable habitat are of equal quality
source subpopulations
in high quality habitats subpopulations that serve as a source of dispersers within a matapopulaiton
sink subpopulations
in low quality habitats subpopulations that rely on outside dispersers to maintain the subpopulation within a metapopulation
landscape metapopulation model
a population model that considers both differences in the quality of the suitable patches and the quality of the surrounding matrix
rescue effect
the phenomenon of dispersers supplementing a declining subpopulation that is headed toward extinction
