1. Population Ecology

2. Population Dynamics Population:
All the individuals of a species that live together in an area
Demography:
The statistical study of populations, allows predictions to be made about how a population will change
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

3. Three Key Features of Populations
Size: number of individuals in an area
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

4. Three Key Features of Populations
Density: measurement of population per unit area or unit volume
Pop. Density = # of individuals ÷ unit of space
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

5. Your class went out to the wetland across the street to conduct a bird count for the local Audubon Society.   
You counted 24 pileated woodpeckers living on 72 acres of land. What was the population density of woodpeckers in this wetland area??

6. Measuring density of populations is a difficult task.
We can count individuals; we can estimate population numbers.
Fig. 52.1
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

7. Density is the result of a dynamic interplay between
processes that add individuals to a population and those that remove individuals from it
Births and immigration add individuals to a population.
Births
Immigration
PopuIation size
Emigration
Deaths
Deaths and emigration remove individuals from a population.

8. Population Dispersion

9. How Do Populations Grow?
Idealized models describe two kinds of population growth:
Exponential Growth
2. Logistic Growth

10. Exponential Growth Curve
Figure 35.3A

11. Logistic Growth Curve

12. Carrying Capacity Carrying Capacity (k):
The maximum population size that can be supported by the available resources
There can only be as many organisms as the environmental resources can support
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

13. Limiting factor
Are those elements that prevent a population from attaining its biotic potential. Limiting factors are characterized into density-dependent and density-independent factors.

14. Population Change and Population Density
In density-independent populations
Birth rate and death rate do not change with population density
In density-dependent populations
Birth rates fall and death rates rise with population density

15. Examples??

16. Density-dependent
Factors are those agents whose limiting effect become more intense as the population density increases. This is a type of negative feedback.
Examples?
Transmission rates of parasitism and disease
Competition for resources (food, space, water, light etc.)
Toxic effects of waste products.
Increased rates of predation

17. The Human Population US Census- POP Clock
Doubled three times in the last three centuries
About 7.4 billion and may reach 9.3 billion by the year 2050
Improved health and technology have lowered death rates

18. Human Population Growth
J curve growth
Grows at a rate of about 80 million yearly
r =1.3%
Why doesn’t environmental resistance take effect?
Altering their environment
Technological advances
The cultural revolution
The agricultural revolution
The industrial-medical revolution

19. Age structure Is commonly represented in pyramids Figure 52.25
Rapid growth Afghanistan
Slow growth United States
Decrease Italy
Male
Female
Age 8 6 4 2
Percent of population
80–84
85
75–79
70–74
65–69
60–64
55–59
50–54
45–49
40–44
35–39
30–34
20–24
25–29
10–14
5–9
0–4
15–19

20. History of the Human Population