chapter 12 – life histories
DESCRIPTION
Lifespan: 2,000 Yrs Seed Production: MillionsTRANSCRIPT
Redwood (Sequoia sempervirens)
Chapter 12 – Life Histories
Lifespan: 2,000 Yrs
Seed Production: Millions
Pacific Salmon (Oncorhynchus spp.)
Salmon: Anadromous
Lifespan: 2-7 Years
Egg Production: Thousands
8 Mayfly Hatch
9
Adult Lifespan: One Day
Egg Production: Hundreds
Mayfly
Lifespan: 2000 YearsSeed Production: Millions Lifespan (Adult): 1 Day
Egg Production: Hundreds
Lifespan: 2-7 YearsEgg Production: Thousands
LIFE HISTORY TRAITS
Life History TraitsStudy of Adaptations that Influence …
• Reproductive Output
• Size of Offspring
• Growth Rate
• Age at Reproductive Maturity
• Competitive Ability
• Life Span
Available Energy is Limited
UNDERSTANDING LIFE HISTORY TRAITS
A) OFFSPRING NUMBER VERSUS SIZELIFE HISTORY CHARACTERISTICS
Sturgeon
Trout
Angel Fish
Fig. 12.4 in Molles 2008
Number of Eggs versus Egg Diameter
Evolutionary Consequences of Life History Traits
RR, Rr
rr
“Hypothetically”
High Gene Flow Among Populations(p = frequency of R allele; q = frequency of r allele)
Population A(p = .80, q = .20)
Population B(p = .78, q = .22)
Population A(p = .82, q = .18)
Low Gene Flow Among Populations(p = frequency of R allele; q = frequency of r allele)
Population A(p = .80, q = .20)
Population B(p = .40, q = .60)
Population A(p = .20, q = .80)
Fig. 12.5 in Molles 2008
Evolutionary Consequences of Life History Traits
Fig. 12.6 in Molles 2008
A) OFFSPRING NUMBER VERSUS SIZELIFE HISTORY CHARACTERISTICS
Fig. 12.7 in Molles 2008
Life History Patterns
Seed Mass versus Plant Growth Form
Graminoid
Forb
Woody
Climbers (Vines)
Fig. 12.8 in Molles 2008
Seed Mass versus Plant Growth Form
Seed Mass versusSeed Dispersal Strategies
Unassisted (Mustard)
Wind(Cottonwood)
Adhesion(Snakeroot)
Elaiosome(Poppy)
Aril(Pomegranite)
Scatterhoard(Walnut)
Fig. 12.8 in Molles 2008
Seed Mass versus Dispersal Mechanism
LIFE HISTORY CHARACTERISTICSB) 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
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?)
Figs. 12.15, 12.16 in Molles 2008
Variation in Survivorship Among Populations of Pumpkinseed
Age at Maturity versus Adult Survivorship(Age at Maturity versus Adult Mortality)
Fig. 12.17, 12.18 in Molles 2008
Available Energy is Limited
UNDERSTANDING LIFE HISTORY TRAITS
Different Ecosystems, Different Challenges and Opportunities
24
Evolutionary Strategies for Coping with Different Ecostystems
R selection K selection
• MacArthur and Wilson 1967 (Birds, Insects)• Pianka 1970, 1972 (Lizards)
Variable, UnpredictableEnvironment
Fairly Constant, PredictableEnvironment
Life History Classification
Table 12.1 in Molles 2008
Fig. 12.20 in Molles 2006
Life History Classification of Plants(Grime 1977, 1979)
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26
27
Grime’s Variable # 1 (Environmental): DEGREE OF STRESS
2
Grime’s Variable # 2 (Environmental): DEGREE OF DISTURBANCE
28
29
Grime’s Variable #3 (Biotic): INTENSITY OF COMPETITION
7
8
Fig. 12.21 in Molles 2006
Life History Classification of AnimalsWinemiller and Rose (1992)
A) OPPORTUNISTIC
B) PERIODIC
C) EQUILIBRIUM
Equilibrium Life History
Cavefishes, Marine Catfishes
Periodic Life History
Cod, Tuna, Ocean Sunfish
Opportunistic Life History
Anchovy, Silverside, Killifish, Mosquitofish
Fig. 12.22 in Molles 2006
Life History Classification of AnimalsWinemiller and Rose (1992)