APES unit 4: populations

government strategies to increase birth rates

baby bonuses or subsides, increased access to postnatal care, parental leave etc

disadvantages of declining birth rates/population sizes

major cities grow but towns dwindle, harder to access prenatal and postnatal care bc less demand for the services, older age of retirement w no younger populations to support the aging ones

advantages of declining birth rates/population sizes

smaller populations could lead to higher quality of life, lower carbon emissions and more equal societies

how does age at marriage or first child influence fertility rates?

younger = typically higher fertility rates

how does access to family planning affect birth and fertility rates?

more access = typically lower fertility rates

how do education and employment opportunities for women affect birth and fertility rates?

more opportunities = typically lower fertility rates

how do government acts and policies affect birth and fertility rates?

more incentives like lower costs or pensions = typically higher fertility rates

how do religious or cultural norms affect birth and fertility rates?

less normalization of or access to contraceptives = typically higher fertility rates

factors that influence birth and fertility rates

-age of marriage and first child

-educational and employment opportunities for women

-access to family planning

-government acts and policies

-religious or cultural norms

infant and child mortality rate (ICM)

# of (infant or child) deaths for every 1,000 live births

infant mortality vs child mortality

infant mortality = death before 1st birthday

child mortality = death before 5th birthday

crude death rate (CDR)

the # of deaths per 1,000 people in a year

crude birth rate (CBR)

the # of live births per 1,000 people in a year

replacement rate in industrialized countries

2.1

0.1 accounts for factors like infant/child mortality and sex ratio (around 105 boys for every 100 girls born)

replacement rate

the total fertility rate needed for a population to replace itself from one generation to the next

2.1 for industrialized countries but higher in developing countries

top 3 most populous countries

1. India (~1.5 billion)

2. China (~1.4 billion)

3. United States (~350 million)

which ages are considered reproductive

15-49

total fertility rate (TFR)

the average # of children per woman in a population

what is the 1st stage of the demographic transition called?

high stationary

what are the 3 lines on the demographic transition model?

birth rate, death rate, and total population size

what is the demographic transition?

a model that describes the transition from high birth and death rates to lower birth and death rates as a country develops

what is the second stage of the demographic transition called

early expanding

what is the third stage of the demographic transition called

late expanding

what is the fourth stage of the demographic transition called

low stationary

what is the fifth stage of the demographic transition called

declining

DTM stage 1

seen in a few remote groups

high CBR

high CDR

slow increase in population

high CBR because many children die at an early age, and children are needed for farming. no family planning and usually cultural encouragement

high CDR because of disease, famine, poor medical knowledge. high ICM

DTM stage 2

seen in egypt, kenya, india

high CBR

rapidly declining CDR

rapid increase in population

high CBR because many children die at an early age, and children are needed for farming. no family planning and usually cultural encouragement

declining CDR and ICM because of improvements in medical care, water supply, and sanitation

DTM stage 3

seen in brazil

falling CBR

slowly falling CDR

slowly increasing population

falling CBR because fewer children are needed for labor

falling CDR because of improved medical care, diet, water supply and sanitation

DTM stage 4

seen in USA, japan, france, UK

low CBR

low CDR

stable/slow increase in population

low CBR due to family planning, women's rights, and later marriages

low CDR due to good health care and reliable food supply

DTM stage 5

seen in germany

very low CBR

low CDR

slow decrease in population

low CBR due to family planning, women's rights and later marriages

low CDR due to good health care and reliable food supply

age structure diagrams (population pyramids)

visual representations of age structure within a country for male and female individuals

rapid growth age structure diagram shape

wide base and narrow top

slow growth age structure diagram shape

relatively consistent shape

zero growth/decline age structure pyramid shape

narrower base with heavier top

population momentum

continued population growth even after fertility drops to or below replacement level

survivorship curves

represent patterns of species survival as a function of age

log scale better allows focus on per capita effects vs actual # of individuals dying

type I survivorship

"late loss"

k-selected, most individuals survive to adulthood, most deaths occur in older ages

humans, other large mammals

type II survivorship

"constant loss"

face threats over entire lifetime due to resources and predation

songbirds, lizards, jellyfish

type III survivorship

"early loss"

r-selected

very high infant mortality due to lack of parental protection

rats, insects, trees

life expectancy (LE)

average age of death in a population

density dependent factors

factor that limits a population more as population density increases

density dependent factors examples

competition for resources, infectious disease, waste accumulation

density independent factors

limiting factors whose influence is not affected by population density

density independent factor examples

natural disasters (wildfires, hurricanes, severe weather etc), pollution

crude growth rate (CGR)

net number added per 1,000 individuals per year

CGR equations (2)

CGR = CBR - CDR

CGR = [ (Inputs - Outputs) / total population ] x 1,000

percent growth rate (%GR) equation

[ (Inputs - Outputs) / total population ] x 100%

doubling time (Td)

the number of years it takes a population to double in size

doubling time (Td) equation

Td = 70/%GR

megacities

cities with more than 10 million people

how many megacities in 2018? how many predicted by 2030?

33 in 2018

predicted to be 43 in 2030

how many megacities are in the global south?

27 of the 33

urban sprawl

expansion of cities into the suburbs

why does urban sprawl occur?

population growth, demand for larger homes/more space, economic incentives that favor low-density development etc

impacts of urban sprawl

loss of ecosystems, farmland, and natural land cover

how does urbanization disrupt the water cycle?

impermeable/impervious surfaces like cement and pavement decrease infiltration (GW recharge), increase runoff, and increase pollutants in waterways

less green cover decreases transpiration

methods to reduce urban runoff

replacing traditional pavement with permeable pavement, planting trees, increasing use of public transit, and building up instead of out

urban "heat island" effect

the phenomenon in which urban areas are warmer than the surrounding countryside

high temp due to:

- low albedo of manmade materials

- greater solar absorption

- high temperatures released from vehicles, fuel boilers for heating etc

low humidity due to:

- impervious land cover and little vegetation meaning most precipitation becomes runoff into storm rains

- low evapotranspiration from plants

methods to reduce urban "heat island" effect

planting trees, green roofs, cool roofs that increase reflectivity, cool pavement

water distribution w natural ground cover (0% impervious surfaces)

40% evapotranspiration, 10% runoff, 50% infiltration

water distribution w low-density residential like rural (10-20% impervious surfaces)

38% evapotranspiration, 20% runoff, 42% infiltration

water distribution w medium density residential like suburbs (30-50% impervious surfaces)

35% evapotranspiration, 30% runoff, 35% infiltration

water distribution w high density residential/industrial/commercial (75-100% impervious surfaces)

30% evapotranspiration, 55% runoff, 15% infiltration

the tragedy of the commons

the tendency of a shared, limited resource to become depleted because people act from self-interest for short-term gain

real world examples of tragedy of the commons

overfishing, water use, deforestation (agriculture or lumber driven), public parks mistreated

methods to prevent tragedy of the commons

assigning private property

government regulation like fines or limits

creating sustainable solutions like reusable bags vs plastic ones

ecological footprint

the impact of a person or community on the environment, expressed as the amount of land required to sustain their use of natural resources.

expressed in global hectares (2.5 acres)

contributors to ecological footprint

food production (especially meat), housing (space and materials), products, electricity production, waste

ecological assets

natural resources that can provide ecological products and services for human being

ecological deficit

footprint is larger than biological capacity for replenishment

how can a region in ecological deficit meet its demand?

importing, liquidating its assets (like overfishing) etc

if a region's assets exceed its ecological footprint, it has an _____

ecological reserve

earth overshoot day

the date when humanity's demand for ecological resources and services (Ecological footprint) in a given year exceeds what earth can regenerate in that year