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Chapter 12 – Life Histories. Redwood ( Sequoia sempervirens ). Lifespan: 2,000 Yrs. Seed Production: Millions. Pacific Salmon ( Oncorhynchus spp .). Salmon: Anadromous. Egg Production: Thousands. Lifespan: 2-7 Years. 8. Mayfly Hatch. 9. Egg Production: Hundreds.
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Chapter 12 – Life Histories Redwood (Sequoia sempervirens)
Lifespan: 2,000 Yrs Seed Production: Millions
Salmon: Anadromous Egg Production: Thousands Lifespan: 2-7 Years
8 Mayfly Hatch
9 Egg Production: Hundreds Adult Lifespan: One Day Mayfly
LIFE HISTORY TRAITS Lifespan: 2-7 Years Egg Production: Thousands Lifespan: 2000 Years Seed Production: Millions Lifespan (Adult): 1 Day Egg Production: Hundreds
Life History Traits • Study of Adaptations that Influence … • Reproductive Output • Size of Offspring • Growth Rate • Age at Reproductive Maturity • Competitive Ability • Life Span
UNDERSTANDING LIFE HISTORY TRAITS Available Energy is Limited
LIFE HISTORY CHARACTERISTICS A) OFFSPRING NUMBER VERSUS SIZE Sturgeon Angel Fish Trout
Number of Eggs versus Egg Diameter Fig. 12.4 in Molles 2008
Evolutionary Consequences of Life History Traits “Hypothetically” RR, Rr rr
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)
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)
Evolutionary Consequences of Life History Traits Fig. 12.5 in Molles 2008
LIFE HISTORY CHARACTERISTICS A) OFFSPRING NUMBER VERSUS SIZE Fig. 12.6 in Molles 2008
Life History Patterns Fig. 12.7 in Molles 2008
Seed Mass versus Plant Growth Form Woody Graminoid Forb Climbers (Vines)
Seed Mass versus Plant Growth Form Fig. 12.8 in Molles 2008
Seed Mass versus Seed Dispersal Strategies Unassisted (Mustard) Adhesion (Snakeroot) Wind (Cottonwood) Scatterhoard (Walnut) Elaiosome (Poppy) Aril (Pomegranite)
Seed Mass versus Dispersal Mechanism Fig. 12.8 in Molles 2008
LIFE HISTORY CHARACTERISTICS B) Adult Survival (Mortality) and Reproductive Allocation
Age at Maturity versus Adult Survivorship Fig. 12.12 in Molles 2008
Age at Maturity, Reproductive Effort versus Adult Mortality Figs. 12.12, 12.13 in Molles 2008
Evolution of Life History Characteristics: Within Species Variation? (Are Age at Maturity, Reproductive Output Related to Adult Survivorship?)
Variation in Survivorship Among Populations of Pumpkinseed Figs. 12.15, 12.16 in Molles 2008
Age at Maturity versus Adult Survivorship (Age at Maturity versus Adult Mortality) Fig. 12.17, 12.18 in Molles 2008
UNDERSTANDING LIFE HISTORY TRAITS Available Energy is Limited
Different Ecosystems, Different Challenges and Opportunities
Evolutionary Strategies for Coping with Different Ecostystems 24
Life History Classification R selection K selection Fairly Constant, Predictable Environment Variable, Unpredictable Environment • MacArthur and Wilson 1967 (Birds, Insects) • Pianka 1970, 1972 (Lizards)
Life History Classification of Plants (Grime 1977, 1979) Fig. 12.20 in Molles 2006
Grime’s Variable # 1 (Environmental): DEGREE OF STRESS 26 25 27
Grime’s Variable # 2 (Environmental): DEGREE OF DISTURBANCE 2 28 29
Grime’s Variable #3 (Biotic): INTENSITY OF COMPETITION 7 8
Life History Classification of Animals Winemiller and Rose (1992) A) OPPORTUNISTIC B) PERIODIC C) EQUILIBRIUM Fig. 12.21 in Molles 2006
Equilibrium Life History Cavefishes, Marine Catfishes
Periodic Life History Cod, Tuna, Ocean Sunfish
Opportunistic Life History Anchovy, Silverside, Killifish, Mosquitofish
Life History Classification of Animals Winemiller and Rose (1992) Fig. 12.22 in Molles 2006