1. Honors Biology Ch. 4 PopulationBiology

2. Ch. 4 Population Biology I.Population Dynamics Constant Population: Birth rate = Death rate

3. Biotic Potential vs. Environmental Resistance

4. A.Biotic Potential vs. Environmental Resistance 1.Biotic Potential: - factors that increase population level

5. a.Birth rate: -number of births, eggs laid, seeds or spores b.Recruitment: -becoming part of breeding pop. -Salmon: high birth rate, low recruitment - Humans: low birth rate, high recruitment

6. Short vs. Long Life History

7. c.Migration d.Adaptibility, Defense, Resistance -if all conditions are favorable, a population explosion (rare) could occur

8. a.Abiotic factors: - temperature, water, fire, etc. b.Biotic factors: - predators, parasites, disease, food -constantly readjusting (dynamic) 2.Environmental Resistance:

9. 3.Exponential Growth

10. -population growth pattern showing an increasing growth rate -can result in a population explosion

11. 3.Exponential Growth (i) Reproductive Age 4 (ii) Reproductive Age 6

12. 4.Carrying Capacity (biotic potential) Carrying Capacity Number of Individuals Time Exponential Growth Equilibrium (environmental resistance)

13. 4.Carrying Capacity -the number of organisms of a species that a particular habitat can support

14. Boom-and-bust Population Cycle Conditions good: Boom; Conditions bad: Bust Annual lake algal bloom

15. Effects of Exceeding Carrying Capacity 1911 - 25 reindeer introduced 1938 - 2000 reindeer 1950 - 8 reindeer survived St. Paul Island, Pribilof, Alaska

16. Lemming Population Cycles

17. 5.Density Dependent Factors: -environmental resistance increases as population increases -predators, disease, parasites, competition

18. 6.Density Independent Factors: - drought, fire, tsunami, floods, volcanoes, salinity - affect a population regardless of its density

19. B.Mechanisms of Population Balance 1. Predator/Prey

20. - lynx vs.hare

21. 2.Host/Parasite: - similar - more common - provides more stability

22. 2.Host/Parasite: weevil vs. wasp

23. 3.Principle of Ecosystem Stability: -Species diversity provides ecosystem stability

25. - Natural enemies provide balance - Evolved together - Introduced species create imbalances

26. 3.Principle of Ecosystem Stability: -Species diversity provides ecosystem stability -Natural enemies provide balance -Evolved together -Introduced species create imbalances

27. II.Human Population Growth A.Human Population Explosion

29. -started around 1830 - 1 billion added every 12 years -How many can the biosphere support?

30. B. Demography - the study of human population growth

31. Pop. Growth Rates: Developed & Developing Countries Developing Countries Developed Countries

32. Age-Structure Diagrams Post-Reproductive (46-100 y old) Reproductive (15-45 y old) Pre-Reproductive (0-14 y old) ExpandingStableContracting

33. Age Structures Developed Country

34. Age Structures Developing Country

35. The End