unit 3 - populations

specialists

smaller range of tolerance; more prone to extinction

generalists

larger range of tolerance; broader niche making them less prone to extinction

k-species

lower birth rate; high parental care; long lifespan

r-species

high birth rate; low parental care; shorter lifespan; more invasive

type 1 curve

usually k-species; low infant mortality rate; rapid decrease in older age

type 2 curve

steady decreasing throughout lifet

type 3 curve

usually r-species, high infant mortality rate; few make it to old age

carrying capacity

maximum number of individuals in a pop that an ecosystem can support

overshoot

when a population briefly exceeds carrying capacity

consquences of overshoot

resource depletion

die off

sharp decrease in pop size when overshoot leads to many individuals dying

size

total number of individuals in a given area at a given time

density

number od individuals in a given area

distribution

how individuals in a population are spaced out compared to each other

types of distribution

random, uniform, clumped

sex ratio

closer to 50 : 50 is more ideal; skewed ratio can lead to limiting population growth

density dependent factors

factors that depend on size; large pop experience this things, small don’t; competition, water, light

density independent factors

factors that are independent of size; flood, fire, tornado

biotic potential

max potential growth rate with no limiting resources; exponential growth

environmental resistance

hits carrying capacity; logistics growth

if 0-14 cohort > 15-44 cohort

represents current + future growth for nation

if 0-14 cohort is equal to 15-44 cohort

represents slight growth / stable population for country

if 0-14 cohort < 15-44 cohort

represents population decline for nation

extreme pyramid shape

rapid growth

less extreme pyramid shape

slow, stable growth

house shape

stable, little to no growth

narrowest @ base shape

declining population

total fertility rate (tfr)

avg number of children a woman in a population will bear throughout her lifetime

replacement level fertility

the TFR required to offset deaths in a population and keep population size stable

infant mortality rate (imr)

number of deaths of children under 1 per 1,000 in a population

more access to contraceptives + family planning leads to

lower tfr

higher education for women leads to

lower tfr

malthus theory

humans will reach a carrying capacity limited by food

industrialization

process of economic and social transition from an agrarian (farming) eocn to an industrial one

characteristics of a pre-industrialized country

low gdp; high death rate; high infant mortality; high tfr

characteristics of an industrializing country

decreasing death rate; decreasing infrant mortality rate; rising gdp

characteristics of an industrialized country

low death rate; low infant mortality rate; high gdp; low tfr

stages

1. preindustrial

2. industrializing

3. developed

4. post industrialized