1. Chapter 12 – Life Histories
Redwood (Sequoia sempervirens)

2. Lifespan: 2,000 Yrs
Seed Production: Millions

3. Pacific Salmon (Oncorhynchus spp.)

4. Salmon: Anadromous
Egg Production: Thousands
Lifespan: 2-7 Years

5. 8
Mayfly Hatch

6. 9
Egg Production: Hundreds
Adult Lifespan: One Day
Mayfly

7. LIFE HISTORY TRAITS Lifespan: 2-7 Years Egg Production: Thousands
Seed Production: Millions
Lifespan (Adult): 1 Day
Egg Production: Hundreds

8. Life History Traits Study of Adaptations that Influence …
Reproductive Output
Size of Offspring
Growth Rate
Age at Reproductive Maturity
Competitive Ability
Life Span

9. UNDERSTANDING LIFE HISTORY TRAITS
Available Energy is Limited

10. LIFE HISTORY CHARACTERISTICS
A) OFFSPRING NUMBER VERSUS SIZE
Sturgeon
Angel Fish
Trout

11. Number of Eggs versus Egg Diameter
Fig in Molles 2008

12. RR, Rr rr Evolutionary Consequences of Life History Traits
“Hypothetically”
RR, Rr rr

13. High Gene Flow Among Populations
(p = frequency of R allele; q = frequency of r allele)
Population A
(p = .80, q = .20)
Population A
(p = .82, q = .18)
Population B
(p = .78, q = .22)

14. Low Gene Flow Among Populations
(p = frequency of R allele; q = frequency of r allele)
Population A
(p = .80, q = .20)
Population A
(p = .20, q = .80)
Population B
(p = .40, q = .60)

15. Evolutionary Consequences of Life History Traits
Fig in Molles 2008

16. LIFE HISTORY CHARACTERISTICS
A) OFFSPRING NUMBER VERSUS SIZE
Fig in Molles 2008

17. Life History Patterns
Fig in Molles 2008

18. Seed Mass versus Plant Growth Form
Woody
Graminoid
Forb
Climbers (Vines)

19. Seed Mass versus Plant Growth Form
Fig in Molles 2008

20. Seed Dispersal Strategies
Seed Mass versus
Seed Dispersal Strategies
Unassisted
(Mustard)
Adhesion
(Snakeroot)
Wind
(Cottonwood)
Scatterhoard
(Walnut)
Elaiosome
(Poppy)
Aril
(Pomegranite)

21. Seed Mass versus Dispersal Mechanism
Fig in Molles 2008

22. LIFE HISTORY CHARACTERISTICS
B) Adult Survival (Mortality) and Reproductive Allocation

23. Age at Maturity versus Adult Survivorship
Fig in Molles 2008

24. Age at Maturity, Reproductive Effort versus Adult Mortality

25. Age at Maturity, Reproductive Effort versus Adult Mortality
Figs , in Molles 2008

26. Evolution of Life History Characteristics: Within Species Variation?
(Are Age at Maturity, Reproductive Output
Related to Adult Survivorship?)

27. Variation in Survivorship Among Populations of Pumpkinseed
Figs , in Molles 2008

28. Age at Maturity versus Adult Survivorship
(Age at Maturity versus Adult Mortality)
Fig , in Molles 2008

29. UNDERSTANDING LIFE HISTORY TRAITS
Available Energy is Limited

30. Different Ecosystems, Different Challenges and Opportunities

31. Evolutionary Strategies for Coping with Different Ecostystems24

32. Fairly Constant, Predictable Variable, Unpredictable
Life History Classification
R selection
K selection
Fairly Constant, Predictable
Environment
Variable, Unpredictable
Environment
MacArthur and Wilson 1967 (Birds, Insects)
Pianka 1970, 1972 (Lizards)

33. Table 12.1 in Molles 2008

34. Life History Classification of Plants
(Grime 1977, 1979)
Fig in Molles 2006

35. Grime’s Variable # 1 (Environmental):
DEGREE OF STRESS 26 25 27

36. Grime’s Variable # 2 (Environmental):
DEGREE OF DISTURBANCE 2 28 29

37. Grime’s Variable #3 (Biotic): INTENSITY OF COMPETITION7 8

38. Life History Classification of Animals
Winemiller and Rose (1992)
A) OPPORTUNISTIC
B) PERIODIC
C) EQUILIBRIUM
Fig in Molles 2006

39. Equilibrium Life History
Cavefishes, Marine Catfishes

40. Periodic Life History
Cod, Tuna, Ocean Sunfish

41. Opportunistic Life History
Anchovy, Silverside, Killifish, Mosquitofish

42. Life History Classification of Animals
Winemiller and Rose (1992)
Fig in Molles 2006