APES Unit Study Guide: Population

1.Study each of the age structure diagrams from the following locations. Understand how (a) shows rapid growth, (b) shows slow growth, and (c) shows negative growth patterns.

2. The population growth curve below and to the right, shows the “log phase”, or the exponential growth phase, to be the period during which the population is growing the most rapidly.

3. Density dependent factors that guide population growth are those factors which “depend” upon population size…such as disease causing pathogens and their ability to spread through a population…food supply…and competition.

4. Density independent factors that guide population growth are those factors that would be just as influential in small populations as they are in large… such as temperature, drought, habitat destruction.

5. When birth rate + immigration rate = death rate + emigration, the population growth is zero.

6. Small organisms, that multiply rapidly are “r” strategists. They are well adapted to survive in environments that are rapidly changing. Examples: flies, mice, cockroaches

7. Large (relatively) organisms, that have relatively fewer offspring, spend some time raising them, and live long lives are known as “K” strategists. They are well adapted to stable environments. Examples include elephants, dogs, humans, and oak trees (even though plants don’t generally spend a great deal of time nurturing offspring!)

8. Countries with anitnatalist policies seek to limit population growth by discouraging large families. They may do this through negative sanctions (fines and forced adoptions for families exceeding the legal limits), or positive sanctions (higher paying jobs, free education for your legal-sized family members)

9. The age structure diagram to the right shows a “baby boom”, which resembles a bulge that moves up through time as the “boomers” age.

10. One of the most common occurrences faced by human populations that are growing is habitat destruction, in order to accommodate the needs of the increase.

11. Pre-industrial nations do not notice a change in birth rates, but they do experience a drop in death rates. Once the population is industrial, the birth rates usually drop as well. The death rates continue to drop.

12. The carrying capacity, shown on the graph below (dashed line, marked K) is the maximum population that a given ecosystem can sustain for a defined period of time. It can change seasonally, and is not a fixed quantity.

13. The human population, since the agricultural revolution nearly 10,000 years ago, has been experiencing an “exponential” growth pattern.

14. Spatial distribution patterns of organisms occurs in many ways. There are “clumps” (most common), where similar species congregate together in groups; uniform or “regular” distribution patterns, where all members of a species are evenly spread out in an area; and random pattern (the least common), where individuals within a species are spread out in no specific pattern, and do not influence each other in their distribution at all.

15. The demographic transition model shows the changes in the growth, birth rate, and death rate which a nation experiences as it goes through industrialization.

16. Human population in the last 100 years have experienced a growth, mostly because of a decrease in the death rate.

17. Replacement level fertility in perfect conditions would be 2. Because of increased infant mortality in developing countries, it is slightly higher than that.

18. The countries with the largest populations in the world are: the US; China; India

19. The rule of “70” may be used to determine how many years it will take a population to double.

20. The population of the world will likely continue to rise in the near future, because many people who desire fewer children do not have the means or education to limit their family size. They may lack proper education on contraception, or they may not have the income needed to procure contraception. In these third world countries, children cost very little to bring into the world, and often times, if they survive to adulthood, they provide security for aging parents that the government does not.

21. Know the factors that influence birth and death rates. (increased birth control; education; health care; etc…)

22. Know how to calculate population growth rates based on crude birth/death rates (those based on 1,000). Know how to calculate grow population growth rates (those not based on 1,000).

Gross formula: current population-past populationx 100

Past population

Crude: births and deaths based on 1,000 individuals.

  • Example. In 2007, there were 3,250 births in a city with population of 223,000. Therefore:
    CBR = (3,250/223,000)*1,000
    CBR = 14.57
    So, there were 14.57 births for every 1,000 people in the city.

23. For the free response, understand the population age distribution graphs, and what types of policies (e.g., population, social, economic) governments should the try to institute, in order to regulate population growth, bearing in mind the country’s religious, economic, and social structure.