1. The number of organisms per unit area
Population Density
The number of organisms per unit area

2. Which has a higher population size?
United States
New York City
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3. Which has a higher population density?
United States
New York City
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4. 3 Types of Dispersion
Draw Each
Uniform
Clumped
Random

5. 3 Types of Dispersion 1) Uniform 2) Clumped 3) Random
Ex: ______ __________ ________

6. Type of dispersion: White-Tailed Deer
Uniform
Clumped
Random
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7. Type of dispersion: Black Bear
Uniform
Clumped
Random
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8. Type of dispersion: Bison
Uniform
Clumped
Random
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9. Type of dispersion: Mountain Lion
Uniform
Clumped
Random
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10. Type of dispersion: Seeds dispersed by wind
Uniform
Clumped
Random
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11. Type of dispersion: Caribou
Uniform
Clumped
Random
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12. Limiting Factors
Items that influence population growth
“Limit” growth

13. 1. Density-dependent limiting factors
“Depends” on “density”
a) Affect large, dense populations more than smaller, less- crowded populations

14. Density-dependent limiting factors
Predation:
Fig. 5-7
Wolves & Moose on Isle Royale

15. Predator - Prey

16. Which increases first?
Predator
Prey
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18. Density-dependent limiting factors
ii. Disease & Parasites:
Easily spread in large, dense populations

19. Density-dependent limiting factors
iii. Competition:
Fig Compete for available resources
Food, water, space

20. iv. Crowding & Stress:
The higher population density, the more crowding and stress on individual organisms

21. 2. Density-independent factors
The density of the population DOES NOT MATTER
It doesn’t matter if the population is 5 or 5,000, they will be affected

22. Density-independent factors
Hot/Cold Weather
Fires
Floods/Hurricanes/Tornadoes
Human Activities – toxic waste spills, pesticides, deforestation

23. Population Growth Rate
How fast a population grows
It depends on 4 major factors

24. Population Growth Rate
a) Natality = birthrate
“neonatal intensive care” – newborns/preemies
b) Mortality = death rate

25. Population Growth Rate
c) Emigration – “exit” or leaving population
d) Immigration – “in” or moving into a population

26. Population Growth Rate
Natality – Mortality + Immigration - Emigration

27. If natality is 10, mortality is 6, immigration is 3, and emigration is 2……the net effect on the population is…
+ 21
- 3
+ 3
+ 5
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28. If the original population consisted of 10 individuals, what is the new population size?20 15 5
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29. If birth rate > death rate
The population will increase
The population will stay the same
The population will decrease
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30. If birth rate < death rate
The population will increase
The population will stay the same
The population will decrease
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31. 1. Exponential Growth (J–shaped Curve)
If ideal conditions continue, the population will continue to grow rapidly
Doubling and re-doubling
1, 2, 3, 8, 16, 32, 64, 128……..
Does NOT last long in nature – WHY?

32. Exponential Growth (J–shaped curve)
d) This is current human population growth worldwide
How long can it last?
Discuss

33. Exponential Growth
e) Draw graph

34. 2. Boom and Bust
As ideal conditions continue, population grows exponentially until it reaches a “peak” size (boom) and then crashes (bust)
Ex: Rabbit population

35. Boom and Bust
c) Draw graphs

36. Yeast Population Growth

38. 3. Logistic Growth (S-shaped curve)
a) Exponential growth at first, eventually the population size levels off as the growth rate slows down b) Carrying capacity: Largest number of individuals that the environment can support

39. Logistic Growth
c) Draw graph

40. Logistic Growth (S-shaped curve)
d) Things that prevent the population from getting too big:
Lack of food or water
Home/shelter availability

41. Which of the following are NOT true about exponential growth?
It occurs at the beginning of logistic growth curves
It shows an S-shaped growth curve
It occurs only if ideal conditions exist
Populations have unlimited resources
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42. Reproductive Patterns
r-strategy: rate strategy
Generally are small
Short life spans
Produce many offspring
rat, fruit fly, locusts

43. Reproductive Patterns
k-strategy: carrying capacity strategy
Larger organisms, long life span
Produces few offspring –better chance of survival
Take care of the offspring, usually for a long time
Kangaroo, elephant

44. Reproductive Pattern: Rabbits & Dolphins
Both r-strategists
Both k-strategists
r-strategist & k-strategist
k-strategist & r-strategist
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45. Demography
The study of human population size, density, distribution, movement, and birth and death rates

46. Demographic Transition
A change in a population from high birth and death rates to low birth and death rates

48. Demographic Transition
Stage 1: birth rate & death rate
Stage 2: birth rate & death rate
Stage 3: birth rate & death rate
Stage 4: birth rate & death rate
Discuss & answer questions on Notes handout

49. Zero Population Growth
Birth rate = Death rate

50. Age-Structure Diagram
# of males & females in 3 age groups:
Pre-reproductive stage
Reproductive stage
Post-reproductive stage

52. Age-Structure Diagrams
Fig – predict future population sizes…
Pyramid shaped
(pre-reproductive larger) 
Every age group about the same 
Smaller at the bottom
(pre-reproductive #’s smaller) 

53. Population will increase Population will stay the same
Predict future population sizes: Pyramid shaped (pre-reproductive larger)
Population will increase
Population will stay the same
Population will decrease
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54. Predict future population sizes: Every age group about the same size
Population will increase
Population will stay the same
Population will decrease
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55. Population will increase Population will stay the same
Predict future population sizes: Smaller at the bottom (pre-reproductive smaller)
Population will increase
Population will stay the same
Population will decrease
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57. Education & Demographic Transition
What does the first graph tell us?
What does the second graph tell us?
What is a key factor in reducing the overall worldwide population growth?