ch 8 env science

agriculture

helps people meet their nutritional needs; increased free time

industry

improves sanitation, medicine, and food production

what did advances in agriculture and industry lead to?

longer lifespans and remarkable population growth

infant mortality

number of babies out of 1000 that die during their first year of life

life expectancy

average number of years a person is expected to live

what does population growth rate describe?

the change in population’s size during a given period of time

population size

number of people

population density

number of people living per mi²

population distribution

how people are distributed within an area

demography

study of human population structure and growth

what do demographers study

historical size and makeup of the populations of countries to make comparison and predictions

what else do demographers study

properties that affect population growth, such as economics and social structure

developed countries

have higher average incomes, slower population growth, diverse industrial economics, and stronger social support systems

developing countries

have lower average incomes, simple and agriculture-based economics, and rapid population growth

semi-developed countries

have both low, middle, and high incomes, population growth is declining from higher numbers, and are working to develop support systems

age structure

classification of members of a population into groups according to age or distribution of members of a population in terms of age groups

what do age structure diagrams help demographers?

make predictions

what do countries that have e high rates of growth usually have?

more young people than older people

what do countries that have slow growth or no growth usually have?

even distribution of ages in the population

what do sex ratios describe?

the relative numbers of females and males

what is the typical sex ratio for humans

1.00 for females and 1.06 for males

what can human activity, such as immigration or emigration do?

alter sex ratios

fertility rate

number of births (usually per year) per 1000 women of childbearing age (usually 15 to 44)

replacement level

average number of children each parent must have in order to “replace” themselves

life expectancy

average length of time that an individual is expected to live

what is life expectancy most affected by?

infant mortality, the death rate of infants less than a year old

what is the demographic transition?

model that explains a population’s change from high birthrates and death rates to low birthrates and death rates

pre-industrial stage

birth rates and death rates are high

transitional stage

birth rates are high but death rates are declining

industrial stage

birth rates start to decline; death rates stay low

post-industrial stage

both birthrates and death rates fall to low and stable levels

what are demographic transitions the result of?

economic growth and social changes

environmental impacts

the environmental impact of humans depends on the way they live

what do poorer societies tendon to have?

smaller ecological footprints than affluent societies, but still strain the environment

define affluent

having a great deal of money, property, or valuable possessions

what does poverty often lead to?

land overuse

what can deforestation, flooding, disease, and habit loss become?

common, as land is cleared for farming

what type of government can’t supply clean water or adequate sewage treatment?

overwhelmed governments

what does resource availability affect?

the quality of life