1. Biology Bellwork – 10/17/12
Describe some observations you can make about populations of insects over the course of a year?
The populations of flies or mosquitoes go up in the spring and summer and decline in the fall. Do they die out completely in winter?
A few individuals in each population find places to go over-winter, and some migrate.

2. Biology Bellwork – 10/24/12
Explain how the improvement in shelter can increase the survival rate of a human population.
Adequate shelter provides defense against extremes of the environment such as temperature, precipitation, and wind. In addition, shelter provides defense against biotic factors in the environment such as venomous snakes, mosquitoes, other insects that harbor parasite, and large predators such as wolves and bears. All of these have the potential to shorten the life span of individuals, thereby affecting the human population as a whole.

3. Alternative Assignments
Write a paragraph comparing density-dependent and density-independent factors that can limit human populations.
Imagine that you are a housefly. Write a short comic strip, with illustrations, explaining what it is like to be a r-strategist from a fly’s view-point.

4. Bellwork 10/25/12 Define the followings vocabulary terms:
Carrying Capacity
The maximum number of individuals in a species that an environment can support for the long term.
Limiting Factor
Biotic or abiotic factor that restricts the number, distribution, or reproduction of a population within a community.

5. Population Ecology

6. Population Dynamics Population:
All the individuals of a species that live together in an area at the same time
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.

7. Population Dynamics Three Key Features of Populations Size Density
Dispersion
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.

8. 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.

9. Three Key Features of Populations
Growth Rate:
Birth Rate (natality) - Death Rate (mortality)
How many individuals are born vs. how many die
Birth rate (b) − death rate (d) = rate of natural increase (r)
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.

11. 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.

12. How Do You Affect Density?
Immigration: movement of individuals into a population
Emigration: movement of individuals out of a population
Density-dependent factors: Biotic factors in the environment that have an increasing effect as population size increases (disease, competition, parasites)
Density-independent factors: Abiotic factors in the environment that affect populations regardless of their density (temperature, weather)

13. Factors That Affect Future Population Growth
Immigration + + -
Population
Mortality
Natality -
Emigration

14. Three Key Features of Populations
Dispersion: describes the spacing of organisms relative to each other
Clumped
Uniform
Random
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.

15. Population Dispersion

16. How Are Populations Measured?
Population density = number of individuals in a given area or volume
Count all the individuals in a population
Estimate by sampling
Mark-Recapture Method

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

18. 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.

19. Bellwork – 10/26/12
An employer offers two equal jobs of one hour each for fourteen days. The first pays $10/hour. The second pays only 1 cent the first day, but the rate doubles each day.
Which job would you rather have?
Job #1  $10 x 14 days = $140
Job #2  $ $ $ $ $ $ $ $ $ $ $ $ $ $81.92 = $163.83

20. Exponential Growth Curve
Figure 35.3A

21. Logistic Growth Curve

22. Factors Limiting Growth Rate
Declining birth rate or increasing death rate are caused by several factors including:
Limited food supply
The buildup of toxic wastes
Increased disease
Predation

23. “Booms” and “Busts”

24. Reproductive Strategies
R Strategists
Short life span
Small body size
Reproduce quickly
Have many young
Little parental care
Ex: cockroaches, weeds, bacteria

25. Reproductive Strategies
K Strategists
Long life span
Large body size
Reproduce slowly
Have few young
Provides parental care
Ex: humans, elephants

26. Age Distribution
Distribution of males and females in each age group of a population
Used to predict future population growth

28. 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

29. The Human Population Doubled three times in the last three centuries
About 6.1 billion and may reach 9.3 billion by the year 2050
Improved health and technology have lowered death rates

30. History of the Human Population