chapter 6 Flashcards
population
the individuals that belong to the same species and live in a given area at a particular time
community
all of the populations of organisms within a given area
population ecology
the study of factors that cause populations to increase or decrease
population size
the total number of individuals within a defined area at a given time
population density
the number of individuals per unit area at a given time
population distribution
a description of how individuals are distributed with respect to one another
sex ratio
the ratio of males to females in a population
age structure
a description of how many individuals fit into particular age categories in a population
limiting resource
a resource that a population cannot live without and that occurs in quantities lower than the population would require to increase in size
density dependent factor
a factor that influences an individuals probability of survival and reproduction in a manner that depends on the size of the population
carrying capacity
the limit of how many individuals in a population the environment can sustain
density independent factor
a factor that has the same effect on an individuals probability of survival and the amount of reproduction at any population size
population growth rate
the number of offspring an individual can produce in a given time period minus the deaths of the individual or its offspring during the same period
intrinsic growth rate
the max potential for growth of a population under ideal conditions with unlimited resources
exponential growth model
growth model estimating the size of a population in the future
j shaped curve
the curve of the exponential growth model when graphed
logistic growth model
growth that is intially exponential but slows as population reaches carrying capacity
s shaped curve
the shape of the logistic graph
overshoot
when a population becomes larger than the carryin capacity
die off
rapid decline in population due to death
k selected species
a species with low intrinsic growth rate that causes the population to increase slowly until it reached carrying capacity
r related species
a species that has a high intrinsic growth rate which often leads to population overshoots and die offs
survivorship curve
a graph that represents the distinct patterns of species survival as a function of age
type 1 survivorship curve
a pattern of survival over time in which there is high survival throughout most of the life span but then individuals die in large numbers as they reach old age
type 2 survivorship curve
a pattern of survival over time in which there is a relatively constant decline in survivorship throughout most of the life span
type 3 survivorship curve
a pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood
corridor
strips of natural habitat that connect populations
metapopulation
a group of spatially distinct populations that are connected by occasional movements of individuals between them
inbreeding depression
when individuals with similar genotypes breed with each other and produce offspring that have an impaired ability to survive and reproduce
community ecology
the study of interactions between species
symbiotic relationship
the relationship between two species that live in close association with each other
competition
the struggle of individuals to obtain a shared limited resource
competitive exclusion principle
the principle stating that two species competing for the same limiting resource cannot coexist
resource partitioning
when two species divide a resource based on differences in their behavior or morphology
predation
one animal kills another
parasitoid
predator that lays eggs inside another organism
parasitism
an interaction in which one organism lives on or in another organism
pathogen
a parasite that causes disease in its host
herbivory
an interaction in which an animal consumes a producer
mutualism
an interaction between two species that increases the chances of survival or reproduction for both species
commensalism
one species benefits the other doesnt care
keystone species
species that plays a far more important role in its community than its relative abundance might suggest
ecosystem engineer
a keystone species that created or maintains habitat for other species
ecological succession
the predictable replacement of one group of species by another species over time
primary succession
ecological succession occuring on surfaces that are initially devoid of soil
secondary succession
succession of plant life that occurs in areas that have been distributed but no lost their soil
pioneer species
a species that can colonize new areas rapidly and grow well in full sunshine
theory of island biogeography
a theory that demonstrates the dual importance of habitat size and distance in determining species richness
