Population Growth

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

2. 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

3. 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 ____________

4. 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 = _____________

5. 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

6. 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)

7. Rate of Growth # of Individuals Generations

8. Rate of Growth • __________ biotic potential = ___ per year • Double in size every ___ years • Biotic potential of bacterial = ___% per hour • Doubles in less than an hour http://www.cellsalive.com/cam2.htm

9. 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 ____________

10. 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

11. Limits to Population Growth

12. 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 ____________ .

13. 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.

14. 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.

15. Population Pyramids

16. 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.

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

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

19. The Demographic Transition

20. Overpopulation

21. 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

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

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

24. 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 ____________

25. World Demography