1. Chapter 8 Population Change

2. Overview of Chapter 8 Principles of Population Ecology Reproductive Strategies The Human Population Demographics of Countries Demographics of United States

3. Principles of Population Ecology Population Ecology – Study of populations and why their numbers change over time – Important for Endangered species Invasive species Population – Group of individuals of same species living in the same geographic area at the same time

4. Population Density Population density – The number of individuals of a species per unit area or volume at a given time – Ex: minnows per Liter of pond water

5. Change in Population Size

7. Calculating Population Change CRUDE BIRTH/DEATH RATE are calculated per 1000 people Growth rate Birth rate Death rate Immigration rate Emigration rate r = (b – d) + (i – e)

8. Maximum Population Growth Intrinsic Rate of Growth (Biotic Potential) – Growth rate under ideal conditions – J- Shaped Curve (exponential growth)

9. Environmental Resistance Environmental limits (resistance) – Prevent indefinite reproduction – Unfavorable food, water, shelter, predation, etc. Carrying Capacity (K) – Maximum # of individuals an environment can support – Causes leveling off of exponential growth – S- shaped curve of logistic population growth

11. Check for understanding 4 - I can explain to my peers why populations cant grow in size forever. 3 - I understand what limits populations from growing in size unstopped. 2 - I understand carrying capacity, but need more practice. 1 - huh? Exponential growth? Carrying capacity?

12. Population Crash Overshooting carrying capacity can lead to population crash – Abrupt decline in population density

13. Factors That Affect Population Size Density Dependent Factor – Factor whose effect on population changes as population density changes – Examples: Predation Disease Competition – Sometimes cause Boom-or-Bust Population Cycles

14. Boom-Or-Bust Population Cycles

15. Case Study- Predator Prey Dynamics on Isle Royale As wolf population increases, moose population decreases (and vice versa)

16. Factors That Affect Population Size Density Independent Factors – Factors that affects population size, but is not influenced by changes in population density – Examples: Killing frost Severe blizzard Fire

17. Check for understanding 4 - I can explain to my peers different ways that populations increase in size and factors that limit uncontrollable population growth. 3 - I understand different ways that populations grow and limitations to their growth. 2 - I understand how exponential growth, boom and bust, and carrying capacity, but I need more practice. 1 - I am lost population growth.

18. Reproductive Strategies r-selected species k-selected species -Small body size - Early maturity - Short life span - Large broods - Little or no parental care - Probability of long term survival is low - Mosquitoes and Dandelions - Small broods - Long life span - Slow development - Large body size - Late reproduction - Low reproductive rate - Parental care - Redwood trees and human beings

19. Survivorship

20. Some populations fit two curves Herring Gulls Type III (young) & Type II

21. Check for understanding 4 - I can explain to my peers how reproductive strategies vary from survivorship types. 3 - I understand how reproductive strategies vary from survivorship types. 2 - I understand, I think, but need to review my notes on reproductive strategies and survivorship types. 1 - Aren’t all organisms the same????

22. Human Population Demography – Science of population structure and growth Human Population is J-shaped curve Thomas Malthus – food for people??  famine & disease!!! better crop yields

23. Human Population 1 Billion 1800 2 Billion 1930 3 Billion 1960 4 Billion 1975 5 Billion 1987 6 Billion 1999 6.6 Billion 2006

24. Population Increase in Mexico

25. Projecting Future Populations Population is increasing; why is death rate going down? Growth rate (r) has started to decline Zero-population growth: birth rate and death rate are equal (S – shaped curve) Projections for 2050 – variation due to fertility rate of less developed countries – Low = 7.7 billion – High = 10.6 billion – Most likely = 9.1 billion

26. Demographics of Countries

27. Highly developed countries – Ex: US, Japan, Germany – – low birth rates, low infant mortality rates (6% US; 54% world), long life expectancy (77 US, 67 world), high per-capita GNI PPP ($34,000, $7,000) Developing countries: – moderately developed countries (Ex: Mexico, Thailand) – high infant mortality/birth rates, but declining – less developed countries (Bangladesh, Niger, Ethiopia)

29. Growth rate Doubling time!! – amount of time for an area to double = 70/r (r = growth rate as %) – Which type of country has shorter doubling time? Replacement-level fertility – typically 2.1 children – Total fertility rate (world) is above replacement level (about 2.5) – Impacting factors: infant mortality rate, population momentum by ## of young females, need/lack of need for children to work (rural), education (especially of women!!)

31. Check for understanding 4 - I can explain to my peers zero population growth, total fertility rate, replacement level fertility, and doubling time. 3 - I understand zero population growth, total fertility rate, replacement level fertility, and doubling time. 2 - I understand, I think, but need to review my notes on zero population growth, total fertility rate, replacement level fertility, and doubling time 1 - I understand some of the terms, but not all.

32. Demographic Stages Pre-industrial Stage – Birth and death rates high – poor medical care, limited food supply – Modest population growth Transitional Stage – Lowered death rate – higher education/improved conditions – Rapid population growth Industrial Stage – Birth rate decline – urbanization decreases economic reason for many kids, women educated/work, retirement safety nets reduce it – Population growth slow Post Industrial Stage – Low birth and death rates – Population growth very slow

33. Demographic Stages

35. Age Structure The number and proportion of people at each age in a population

36. Demographics of Specific Countries

37. World-wide 29% of human population is under age 15 Could cause large increase in birth rates

38. Check for understanding 4 - I can explain to my peers all the different demographic stages, why they occur AND how to read age structure graphs. I should just drop out of HS now. 3 - I understand all the different demographic stages, why they occur AND how to read age structure graphs. 2 - I understand demographic transition and age structure graphs, BUT….. 1 - I am lost and need to hear it all again.