Population Growth “People are everywhere. Some people say there are to many of us, but no one wants to leave” - Charles Schulz

How Populations Change Population – a group of ______________ of the same ____________ living in a particular _____________ at a given _______________ ____________ – births ____________– deaths ____________– moving into an area ____________– moving out of an area

How Populations Change Fertility and immigration cause a population to ____________ Mortality and emigration cause a population to ____________ # births + # immigrants __ # deaths + emigrants Population ____________ # births + # immigrants __ # deaths + emigrants Population ____________

How Populations Change _____________ –Life expectancy at birth Average # of years a group of people born in the same year can be _______________ –____________ in most places –Sub-Saharan Africa – average life expectancy at birth = less than _______ »Why so low? –World average = _____________

How Populations Change ____________ –Does migration change the population? –A ___________ event – much less ____________ than fertility/mortality –The number of people ____________ to the US was ____ time higher than those leaving any other country –Over ______________ people immigrated into the US in 2002

Rate of Growth Most species produce ________________ than can ___________ and __________ _____________ – maximum _______ rate –Rate at which a population would grow if every new individual survived to adulthood and reproduced to maximum capacity Each generation would grow ___________ –(____________ curve)

Rate of Growth # of Individuals Generations

Rate of Growth __________ biotic potential = ___ per year –Double in size every ___ years Biotic potential of bacterial = ___% per hour –Doubles in less than an hour

Limits to Population Growth ____________ resources –Food, shelter, mineral nutrients, water, light –Growing populations consume these resources rapidly Some have the ability to limit the growth rate = ____________ Competition ____________  mortality ____________  fertility ____________

Limits to Population Growth Population reaches size in which it can _____________________ –__________________ Maximum number of individuals an environment can support for long period of time –Creates an _______________ curve

Limits to Population Growth

Growing Human Population _____________ is the study of the characteristics of populations, especially ____________ populations. –Demographers study the historical size and makeup of the populations of countries to make comparisons and ____________.

Growing Human Population Developed vs. Developing Countries –____________ countries have __________ average incomes, ____________ population growth, _____________ industrial economies, and _____________ social support systems. –____________ countries have ___________ average incomes, simple and ____________ economics, and ____________ population growth.

Growing Human Population ____________ – the classification of members of a population into groups according to age –Countries that have __________ rates of growth usually have ____________ young people than older people.

Population Pyramids

The Demographic Transition The demographic transition is the general pattern of demographic change from ____ birth and death rates to _______ birth and death rates –observed in the history of more-developed countries –____________ and ____________ progress affects population growth rates.

The Demographic Transition 4 stages 1.____________ –Birth and mortality rates both high –Population is stable 2.____________ –Population explosion –Hygiene, nutrition, and education improve which lowers the mortality rate –Fertility rate still high

The Demographic Transition 3.____________ –Population growth slows because birth rate decreases. As the birth rate becomes close to the death rate, the population size stabilizes. 4.____________ –Birth rate drops below replacement level, so the size of the population begins to decrease.

The Demographic Transition

Overpopulation

____________ –Brought better healthcare and improved availability of food More people  stress on the __________ –Basic facilities of a country or region More people  stress on ____________ Used faster than nature can replace them

Overpopulation Signs of overpopulation –suburban _________, polluted rivers, barren land, inadequate housing, and overcrowded schools. Wood as ____________

Overpopulation Unsafe ____________ –The population of most cities double every __ years ____________ can’t keep up  unsafe water  ____________

Overpopulation Impacts on land –Leads to less ____________ land Land that can be used for ____________ –____________ for agriculture, homes, and natural areas ____________ –Increased ____________ of people living in an urban area  suburban ____________

World Demography