1. Chapter 4 Population Biology
The study of how populations change and what influences these changes.

2. Florida Alligators
These creatures were once endangered. After efforts were made to save the population, they are now considered pests. How did this happen? Ban hunting, Increase fines for poaching, Breed (pits), Eliminate egg eaters

3. Human History
How has the human population changed in the past? 1000 years ago? years ago? now?

4. Animals gather in groups
Why? Protection, Warmth, Strength, Reduce Workload

5. Choose one!
You are hired for a job for only 30 days. How would you like to be paid? A) $100 per day B) 1 cent per day, and it doubles each day Assignment: Graph the amount of money you will make each day. ( x=day, y=$)

6. Population Growth
the change in the size of a population over time Population increase- Birthrate Deathrate Population decrease- Example: WWII (During/ After)

7. Population Growth How fast do populations grow?
Few experience linear growth
Pair of Houseflies  6 trillion if all eggs hatched in 1 summer

8. Linear vs. Exponential Growth

9. Exponential Growth
(J-Curve) Slow start (Lag Phase) until individuals increase, then a rapid increase in number. - No limiting factors Example: Houseflies in summer, Australian rabbits

10. Carrying Capacity (K)
The population that a particular environment can support over an indefinite period of time What determines carrying capacity?

11. Limited Growth S- Shaped Curve
Exponential growth until limiting factors level off population at carrying capacity.
What happens if a population is above carrying capacity?

12. Reproduction Pattern
Rapid Life History (many offspring, little care) Short life-span Ex: House fly, mosquitoes, dandilions Slow Life History (few offspring, much care) Long life-span Ex: Geese, Elephant, Oak tree

13. Types of Population Growth
What type of population growth pattern do humans have?

14. Growth Rate Patterns
Density-dependent Limiting Factors (Cornsmut, gall) Factor increases as the population increases Ex: Disease, competition, parasites, food, space

15. Growth Rate Patterns Density-independent Factors
Factor with no relationship to population
Ex: mostly abiotic (flood, fire, temp., wind)

16. Interactions that Limit Size
1. Predator-Prey Relationship 2. Competition 3. Crowding and Stress

17. Predator-Prey Relationship
Flow of energy
Remove unfit members
Population of one depends on the other
Ex: Lynx-Hare

18. Competition Density-dependent factor In competition for food and mates
Ex: Lichen-grass

19. Crowding and Stress Aggression
Decrease care, fertility, immunity lead to a decrease in population size.
Ex: Zoo animals, trees

20. Crowding and Stress
Can there be under-crowding? If there is too few individuals to find a mate to reproduce. (Giant Panda) Assignment: 4.1 Review 1-5 p. 99

21. Human Population
Section 4-2 Pages

22. Have humans reached K? Lack of natural resources (fossil fuels)
Are we polluting at a rate we can sustain?
(Global warming, Ozone layer)
Running out of land
HIV / Diseases
Should we make laws?

23. Demography
the study of population growth characteristics Demographers study: Population size Density/distribution Movement Birthrate/deathrate

24. Human Population Growth
What can humans do to control their population growth that other organisms cannot? 1. No competing organisms 2. Increase food production 3. Control disease

25. World Population
Average of: 5 births per second -2 deaths per second 3 people gained

26. World Population
Population Growth Rate =Births- Deaths % % *Scientists believe Earth’s K is 10 billion

27. Industrialized Countries Developing Countries Third-World Countries
Types of Countries
Industrialized Countries Developing Countries Third-World Countries

28. Industrialized Countries
US, Canada, England, Japan
Low deathrate, declining birthrate
Little or no growth

29. Developing Countries India and Mexico Low deathrate, high birthrate
Large population growth

30. Third-World Countries
Rwanda, Uganda
Declining deathrate, high birthrate
Moderate population growth

31. Age Structure Pyramids
Does the age of the population matter?
Used to make predictions
Categorized by
Prereproductive 0-14
Reproductive
Post-reproductive 45+

33. Age Structure of Countries 1 2

34. Fertility
the number of offspring a female produces during her reproductive years the population growth of a country depends on its birth rate, death rate, and fertility rate

35. Age Structure example
Page 103 Pre-Reproductive Years Reproductive Years Post-Reproductive Years