Unit 3 Flashcards
A group of individuals that belong to the same species and live in the same area
population
All the different populations that live together in an area
community
the study of factors that cause populations to increase or decrease
population ecology
Number of individuals per unit area
population density
a description of how individuals are distributed with respect to one another
population distribution
ratio of males to females in a population
sex ratio
number of males and females of each age in a population
age structure
a resource that a population cannot live without and that occurs in quantities lower than the population would require to increase in size
limiting resource
factor that limits a population more as population density increases
density-dependent factor
Largest number of individuals of a population that a environment can support
carrying capacity (K)
limiting factor that affects all populations in similar ways, regardless of population size
density-independent factor
explains how fast a given population grows
population growth rate
the maximum potential for growth of a population under ideal conditions with unlimited resources
intrinsic growth rate
a mathematical description of idealized, unregulated population growth
exponential growth model
a growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment
logistic growth model
when a population becomes larger than the environment’s carrying capacity
overshoot
a rapid decline in a population due to death
die-off
a species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity
K-selected species
a species that has a high intrinsic growth rate, which often leads to population overshoots and die-offs
r-selected species
high survivorship until old age and then high death rates
type I survivorship curves
relatively consistent decline in survivorship throughout life
type II survivorship curves
low survivorship early in life and few individuals reach adulthood
type III survivorship curves
strips of natural habitat that connect populations
corridor
A group of spatially separated populations of one species that interact through immigration and emigration
metapopulation
genetically similar parents mate and produce inferior offspring
inbreeding depression
the study of interactions between species
community ecology
close interaction between species in which one species lives in or on the other
symbiotic relationship
A relationship between two organisms in which one organism benefits and the other is unaffected
commensalism
a keystone species that creates or maintains habitat for other species
ecosystem engineer
gradual change in living communities that follows a disturbance
ecological succession
succession that occurs on surfaces where no soil exists
primary succession
Succession following a disturbance that destroys a community without destroying the soil
secondary succession
First species to populate an area during primary succession
pioneer species
historically the final stage of succession
climax community
a theory that demonstrates the dual importance of habitat size and distance in determining species richness
theory of island biogeography
The scientific study of population characteristics
demography
movement of people into a country
immigration
movement of people out of a country
emigration
number of births/deaths per 1,000 individuals per year
crude birth/death rate (CBR/CDR)
the number of years it takes for a population to double
doubling time
The average number of children a woman will have throughout her childbearing years
total fertility rate (TFR)
the total fertility rate required to offset the average number of deaths in a population in order to maintain the current population size
Replacement level fertility
the theory that as a country moves from a subsistence economy to industrialization and increased affluence it undergoes a predictable shift in population growth
theory of demographic transition
Impact = Population x Affluence x Technology
IPAT equation
number of births per 1,000 individuals per year
Crude birth rate (CBR)
number of deaths per 1,000 individuals per year
crude death rate (CDR)
global population growth
(cbr-cdr)/10
population growth of a nation
[(CBR + immigration) - (CDR + emigration)]/10
doubling time equation
70/% growth rate
the difference between immigration and emigration in a given year per 1,000 individuals
net migration rate
age structure diagram common of developed countries that is widest on the bottom and narrowest at the top
population pyramid
continued population growth after growth reduction measures have been taken
population momentum
the theory that a country moves from a subsidence economy to industrialization to increased affluence as it undergoes population growth
theory of demographic transition
ecological footprint of a country
per capita footprint x number of people
a measure of the value of all products & services produced in 1 yr by a country
gross domestic product (GDP)
