Population Growth

1. Population Growth Unit 3

2. Population Characteristics • Population - Group of individuals of the same species inhabiting the same area same time.

3. Immigration add individuals to a population (moving in). • Emigration subtract individuals from a population (moving out).

4. Population Growth Number of births number of deaths + + Number of immigrants number of emigrants

5. Population shrinks Number of deaths number of births + + number of emigrants Number of immigrants

6. POPULATION GROWTH • For most of human history, humans have not been very numerous compared to other species. • In 2011, the world reach 7 billion people • It took nearly 72,000 years to reach 1 billion. • 150 years to reach 3 billion. • 25 years to reach 4 billion. • 20 years to reach 5 billion • 12 years to reach 6 billion. • Human population tripled during the twentieth century..

7. How fast can population grow? • Most organisms can produce more offspring than can survive. • Biotic Potential maximum growth rate for a population • If all every offspring survived and lived into adulthood and they reproduced to max capacity.

8. Maximum potential= J-curve • J- curve is showing exponential growth.

9. Limitations of population growth • Food • Water • Shelter • Other resources (ex: nesting sites, sunlight) • As a population grows more of these resources are needed. • These resources are known as limited resources.

10. Overcrowding risk factors • Overcrowding of population increases exposure to : • Predators • Parasites • Diseases

11. Environmental resistance combined effect of all the factors that limit population growth. • Carrying Capacity maximum population size an environment can support for a long period of time. • Population go above and below the capacity in response to the environment (ex: seasons).

12. Carrying Capacity

13. S-Curve • S- Curve the curved portion of the line that is approaching carry capacity. • This curve occurs in nature.

15. Human Population Growth • Major reason for increasing human population growth rate is an increase in medical care, and a consequential decrease in death rates.

16. From hunting to gathering • For 99 % of our history, humans have been hunters and gathers. •  people who obtain their food by hunting, fishing and gathering wild plant foods.

17. Change to Agriculture • Changing from hunting and gathering to raising crops and animals. Agriculture Revolution • This allowed people to produce more food and stay in one location for a long period of time. • This caused population growth. • Why????

18. Historical Human Population Growth

19. Activity on human population growth.

20. Impacts of human population growth

21. Consequences of Growth • Shortages of fuelwood • Contaminated water • Urban problems • Displacement of people from their homes

22. Fuelwood • Is one of the limited resources in developing countries. • There is often more food to support people, but there is not enough wood. • Why do we need wood?

23. Fuelwood • We need wood to cook food, many people suffer from malnutrition or even starvation. • Wood also insures that a person can boil water. • This sanitizes water. • Without sanitizing the water many suffer from waterborne parasite and diseases.

24. Water that kills • Each year 10 million people die from diseases contracted from dirty water. • In developing nations water is not only used from drinking and cooking but also washing and sewage disposal. • This causes dysentery, typhoid and cholera

25. Lima, Peru

26. In 1991, Lima, Peru was the site of the first cholera epidemic that the Western Hemisphere had experienced in more than 75 years. • These houses are made from plastic packing cases. • No running water and no sewage system.

27. Urban Cities • As a country’s population grows, more people want to live in cities. • Why??

28. Urban Cities • They go to seek education and job opportunities. • Once fertile soil runs out people from the countryside also run to the cities for jobs. • Many of these people will end up homeless on the streets.

29. People in line for one job

30. Social Unrest • Rapid population growth can lead to conflicts between groups competing for scarce resources. • A situation can lead to a civil war when one group monopolizes most of the available jobs. .

31. Social Unrest • This can also cause conflicts between nations. • Water rights When a river flows through one or more nations who has the rights to that water is the water is scarce?

32. Nile River • The Nile river is the main source of water for the nine nations which make up the Nile basin. As is, the water provided by the river is barely enough to satisfy the enormous water demands of the region.

33. Nile River • Access to the Nile's waters has already been defined as a vital national priority by countries such as Egypt and Sudan. It is an issue over which the two nation's have professed themselves willing to go to war over.

34. Nile River

35. Environmental Refugees • Environmental Refugees– People driven from their homes by severe environmental damage.

36. Environmental Refugees • Article and reflection

37. Environmental Refugees • After the power plant explosion on 26 April 1986 at Chernobyl, 10,000 residents had to leave the city because of radiation.

38. Environmental Refugees • Many of these refugees will resettle in another country and overwhelm that country with damage to provide education, healthcare and jobs.

39. How do we Solve Population Growth? • Family Planning • Birth Control • Any Others?

40. Overconsumption • Developed countries like the U.S. have lower birth rates but are using up large portions of the Earths resources and producing huge amount of wastes. • Developed countries contain 21% of the worlds population, consume 75% of the energy, produce 70% CO2 emissions, and produce 90% of the hazardous waste.