ap environmental science - unit 3: populations

affluence

the state of having plentiful wealth including the possession of money, goods, or property

age structure

a description of how many individuals fit into particular age categories in a population

age structure diagram

a visual representation of the number of individuals within specific age groups for a country, typically expressed for males and females

carrying capacity (K)

the limit of how many individuals in a population the environment can sustain

child mortality rate

the number of deaths of children < age 5 per 1000 live births

commensalism

a relationship between species in which 1 species benefits and the other species is neither harmed nor helped

community

all of the population of organisms within a given area

community ecology

the study of interactions between species

competition

the struggle of individuals to obtain a shared limiting resource

competitive exclusion principle

the principle stating that 2 species competing for the same limiting resource cannot coexist

corridor

strips of natural habitat that connect populations

crude birth rate (CBR)

the number of births per 1000 individuals per year

crude death rate (CDR)

the number of deaths per 1000 individuals per year

demographer

a scientist in the field of demography who studies human populations and population trends

demography

the study of human populations and population trends

density-dependent factor

a factor that influences an individual's probability of survival and reproduction in a manner that depends on the size of the population

density-independent factor

a factor that has the same effect on an individual's probability of survival and the amount of reproduction at any population size

developed country

a country with relatively high levels of industrialization and income

developing country

a country with relatively low levels of industrialization and income

die-off

a rapid decline in population due to death

doubling time

the number of years it takes a population to double
DT = 70 / r

ecological succession

the predictable replacement of 1 group of species by another over time

ecosystem engineer

a keystone species that creates/maintains habitat for other species

emigration

the movement of organisms out of a country/region

exponential growth model

a growth model that estimates a population's future size after a period of time, based on the intrinsic growth rate and the number of reproducing individuals currently in the population

family planning

the practice of regulating the number or spacing of offspring through the use of birth control

gross domestic product (GDP)

a measure of the value of all products and services produced in 1 country in 1 year

immigration

the movement of organisms into a country/region from another country/region

inbreeding depression

when individuals with similar genotypes—typically relatives—breed with each other and produce offspring that have an impaired ability to survive and reproduce

infant mortality rate

the number of deaths of infants < age 1 per 1000 live births

intrinsic growth rate (r)

the maximum potential for growth of a population under ideal conditions with unlimited resources

IPAT equation

an equation used to estimate the impact of the human lifestyle on the environment

j-shaped curve

the curve of the exponential growth model when graphed

k-selected species

a species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity

keystone species

a species that plays a far more important role in its community than its relative abundance might suggest

life expectancy

the average number of years that an infant born in a particular year in a particular country can be expected to live, given the current average life span and death rate in that country

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

logistic 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

metapopulation

a group of spatially distinct populations that are connected by occasional movements of species

mutualism

an interaction between 2 species that increases the chances of survival/reproduction for both species

net migration rate

the difference between immigration and emigration in a given year per 1000 people in a country

overshoot

when a population becomes larger than the environment's carrying capacity

parasitism

an interaction in which 1 organism lives on/in another

parasitoid

a specialized type of predator that lays eggs inside other organisms—referred to as its host

pathogen

parasite that causes disease in their host

pioneer species

a species that can colonize new areas rapidly and grow well in full sunshine

population

the individuals that belong to the same species and live in a given 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

population ecology

the study of factors that cause populations to increase/decrease

population growth model

mathematical equations that can be used to predict population size at any moment in time

population growth rate

the number of offspring an individual can produce in a given time period, minus the deaths of the individual/its offspring during the same time period

population momentum

continued population growth after growth reduction measures have been implemented

population pyramid

an age structure diagram that is widest at the bottom and smallest at the top, typical of developing countries

population size (N)

the total number of individuals within a defined area at a given time

predation

an interaction in which 1 animal typically kills and consumes another animal

primary succession

ecological succession occurring on surfaces that are initially devoid of soil

r-selected species

a species that has a high intrinsic growth rate, which often leads to population overshoots and die-offs

replacement-level fertility

the total fertility rate (TFR) required to offset the average number of deaths in a population in order to maintain the current population size

resource partitioning

when 2 species divide a resource based on differences in their behavior/morphology

s-shaped curve

the shape of the logistic growth model when graphed

secondary succession

the succession of plant life that occurs in areas that have been disturbed but have not lost their soil

sex ratio

the ratio of males to females in a population

survivorship curve

a graph that represents the distinct patterns of species survival as a function of age

symbiotic relationship

the relationship between 2 species that live in close association with each other

theory of demographic transition

the theory that as a country moves from a subsistence country to industrialization and increased affluence, it undergoes a predictable shift in population growth

theory of island biogeography

a theory that demonstrates the dual importance of habitat size and distance in determining species richness

total fertility rate (TFR)

an estimate of the average number of children that each woman in a population will bear throughout her childbearing years

type I survivorship curve

a pattern of survival over time in which there is high survival throughout most of the life span, but then individuals start to die in large numbers as they approach old age

type II 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 III survivorship curve

a pattern of survival over time in which there is low survival throughout most of the life span and high levels of mortality early in life, with few making it to adulthood and fewer to old age