1. Every second….5 people are born, 2 people die, ….net gain 3 people.
Population Ecology
Every second….5 people are born, 2 people die,
….net gain 3 people.

2. Population Ecology
Deals with the # of individuals of a particular species that are found in an area and how and why those # change or remain fixed over time.

3. Population ecologists study…
How populations respond to its environment
Competition for resources, predations, disease and other environmental pressures

4. Population Growth J-shaped curve
1. Exponential growth– growth rate under ideal conditions
2. Uncheck growth (carrying capacity not yet met)

5. J-shaped
Exponential growth!

6. S-Shaped Curve
1. An S-shaped curve shows that the population grows slowly at first & then increases more and more quickly.

7. S-Shaped Curve

8. 2. At carrying capacity, growth of the population will remain the same.

9. 3. Carrying capacity is the number of organisms that an environment can support indefinitely.

10. a. Births will approximately equal deaths.
B. When the population overshoots the carrying results in LIMITING factors death to outnumber births.

11. C. Limiting Factor is a factor that will limit population growth.
1) Food availability
2) Disease
3) Predators
4) Space

12. Reproductive Patterns
A. Rapid life history (example: mosquitoes)
a. Rapid reproduction
b. High number of offspring

13. Reproductive Patterns
c. Small body size
d. Organisms mature rapidly
e. Reproduce early
f. Organisms have a short life span

14. B. Slow life history (example: elephant)
a. Slow reproduction
b. Low number of offspring
Large body size

15. d. Organisms mature slowly e. Reproduce late in life f
d. Organisms mature slowly e. Reproduce late in life f. Organisms have a long life span g. Organisms tend to have parental care

16. Population density & growth
Population density is the number of individuals in a given area.

17. Density–DEPENDENT factor
Factor that limits population size or density

18. A. Disease (example: HIV)
B. Competition
C. Predators
D. Parasites
Food
Water
Territory

19. Density -INDEPENDENT factor:
Usually a weather related event.
It affects ALL populations regardless of size.

20. A. Temperature
B. Storms
C. Floods
D. Drought
E. Volcanic eruption

21. Predator-prey relationship
Predators affect prey populations
B. Prey affect predator populations

22. Intraspecies competition
A. Space
B. Food
C. Water
D. Reproduction

23. Invasive Species –
uncontrolled competition

24. Project World Population Growth
Demography
Study of HUMAN population size, density, distribution, movement, BIRTH rates & death rates.

25. World Population Growth

26. Year Population 1 200 million 1000 275 million 1500 450 million 1650
1750
700 million
1804
1 billion
1850
1.2 billion
1900
1.6 billion
1927
2 billion
1950
2.55 billion
1955
2.8 billion
1960
3 billion
1965
3.3 billion
1970
3.7 billion
1975
4 billion
1980
4.5 billion
1985
4.85 billion
1990
5.3 billion
1995
5.7 billion
1999
6 billion
2006
6.5 billion
2009
6.8 billion
2011
7 billion
2025
8 billion
2050
9.4 billion

27. Humans can alter their environment thus affect the POPULATION GROWTH RATE.

28. 1. Famine
2. Eradicate Disease
3. War
4. Better food production

29. Calculating Growth Rate
Growth rate (r) = birth rate (b)+ I – death rate (d) + E

30. Immigration – movement of individuals into a population
Emigration – movement of individuals into a population

31. Doubling time – time needed for population to double in size
Zero population growth – birthrate = death rate

32. Birthrate – number of live births per 1000 in a given year
Death rate – number of deaths per 1000 in a given year

33. Demographics of Countries
Demographics – applied science that deals with population statistics.

34. Developed countries
1. Low birth rates
2.Low infant mortality rates. (the # of infant deaths per 1000 live births)

35. Developed countries 1996 US 7.5/1000 for infant morality
World average 62/1000

36. Developed countries
3.Usually have longer life expectancy

37. Developed countries
4.Examples of developed countries:
US, Canada, Sweden, Germany, France, Australia, Japan

38. (most S. American nations)
Developing Countries
Moderately developed countries
Examples:
1. Mexico
2. Turkey
3. Thailand
(most S. American nations)

39. Examples: 1. Bangledesh 2. Niger Ethiopia Laos Cambodia
Less developed countries
Examples:
1. Bangledesh
2. Niger
Ethiopia
Laos
Cambodia

40. These countries have …………
High birth and mortality rates than developed countries
Short life spans

41. Another factor to examine is the replacement level fertility
Another factor to examine is the replacement level fertility. This is number of children a couple must have to “replace” themselves. Replacement rate is 2.1 children in developed countries.

42. The replacement rate in developing countries is 2.7 children.

43. Age Structure of Countries
In order to predict future population it is important to know the age structure.

44. Age Structure of Countries
Age structure is the number and proportion at each age in a population. The number of males and females at each age.

45. The overall structure of the age tells whether the population is increasing, stable or shrinking.

46. Stable growth – approximately the same number of individuals at each age grouping

47. Rapid growth – a large proportion of the population is 19 years old or younger

48. Slow growth – a large proportion of population is 55 years old or younger

49. Declining growth – the largest portion of the population is 20-40 years, smaller groups are younger