1. HUMAN POPULATION GROWTH AND OTHER THREATS TO BIODIVERSITY

2. Scientists believe that the first modern humans evolved on Earth approximately 100,000 years ago. Hunter-gatherers – humans that roamed the forests/plains and lived in small tribes or families. Predation, Starvation, and disease prevented them from living long, 35 years old was considered very old. 10,000-20,000 years ago, people began to establish settlements and store their food which reduced the threats of starvation.

3. - This shift from harvesting wild food sources to producing food through farming and herding is known as agricultural revolution. - Farming provided a steady and increased food supply which led to an increase in human population.

4. A sharp decline occurred during the mid-fourteenth century. Result of bubonic plague or Black death that struck Asia and Europe. Worldwide outbreaks of malaria, smallpox, yellow fever, and cholera claimed hundreds of thousands of lives. Irish Potato Famine- resulted in more than 1 million deaths Famine in China (1877-1888)- resulted in more than 9 million deaths War- have a destructive effect on human population

5. Population growth depends on rates of birth, death, immigration, and emigration. 1. Emigration- movement of people out of a country 2. Immigration- movement of people into a country 3. Birth rate-expressed as # of births per 1000 per year 4. Death rate-expressed as # of deaths per 1000 per year

6. The human population has been growing exponentially for centuries. The most significant additions to human populations are due to births. Total fertility rate (TFR): the average number of children a woman has during her reproductive years. Replacement-level fertility: the number of children a couple must bear to replace themselves.

7. C. Factors Influencing Total Fertility Rates: - availability of birth control and abortions. -Education level of women. -populations religious beliefs, customs, culture and traditions. - demand for children in the work force. -existence of retirement systems- pensions. -Marriage age. -Urbanization.

8. The baby bust that followed the baby boom was largely due to delayed marriage, contraception, and abortion.

9. Population growth is considerably higher because the death rate has dropped. People live longer & lower infant mortality rates exist. Due to: 1. Industrial Revolution- improved standards of living. 2. Clean water sources. 3. Better sanitation. 4. Dependable food supplies. 5. Better health care.

10. A population’s growth is dependent upon the number of people in young, middle, and older age groups. # of people younger than age 15 = the major factor determining a country’s population growth. Populations with a large proportion of its people in the pre-reproductive ages 1-14 have a large potential for rapid population growth.

12. 32% of the people in developing countries were under 15 years old in 2006 versus only 17% in developed countries.

13. 1- Birth rate exceeds the death rate. Population is getting larger. Pyramid shaped histogram. EX: Kenya, Nigeria and Saudi Arabia.

14. 2- Birth rate almost equals death rate. The population is not getting any larger or is growing very slowly. Histogram shape is straighter and more box-like until about age 45-85. EX. US, Australia & Canada has slow growth. Denmark, Austria and Italy has stable growth.

15. 3- When the birth rate is smaller than the death rate. The pyramid bulges near the top or is inverted. EX: Germany, Bulgaria & Hungary

16. Q: Which is the largest age cohort? Q: What do you think this says about population change? Q: What do you think would happen if the pre- reproductive cohort was larger than the cohorts above it?

19. COUNTRY QUESTIONS 1. What can you tell about your country’s growth rate by looking at your histogram? 2. How you tell from the data if there are more boy babies or girl babies in each country? 3. Determine the percentage of the population that has yet to reach childbearing age. 4. What do these numbers say about future growth in the country? 5. Are there more elderly (>65 yrs) women or men? a. Why might this be the case?

20. ALL OF THE COUNTRY QUESTIONS 1. Can you tell from the graphs which country has the most people a. Why or why not? 2. Which country has the most people? a. How can you tell? 3. Of the six graphs, which looks most like a pyramid: a. What does this indicated about their population growth rate? b. What factors would change the shape of the pyramids in the future?

21. 5. Which countries appear to have the slowest rates of population growth? a. How can you tell? 6. What country do children (<15 yrs) make up the biggest % of the population? 7. How can this change a countries future growth? 8. Do any of your group’s six countries have a baby boom in it (a bulge somewhere in the middle of the histogram)? What could account for this?

23. Resource depletion Resource degradation Pollution Loss of biodiversity