Redwood (Sequoia sempervirens)

1

Chapter 12 – Life Histories

4

3

2Lifespan: 2,000 Yrs

Seed Production: Millions

Pacific Salmon

Salmon: Anadromous

10

11

12Lifespan: 2-7 Years

Egg Production: Thousands

8 Mayfly Hatch

7 Mayfly (Adult)

9

Adult Lifespan: One Day

Egg Production: Hundreds

12

13

14

Lifespan: 2000 YearsSeed Production: Millions

Lifespan (Adult): 1 DayEgg Production: Hundreds

Lifespan: 2-7 YearsEgg Production: Thousands

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

13 14

A) OFFSPRING NUMBER VERSUS SIZE

LIFE HISTORY CHARACTERISTICS

1516

Life History Patterns

Fig. 12.6 in Molles 2006

Fig. 12.7 in Molles 2007

Life History Patterns

18

Fig. 12.2 in Molles 2006

Fig. 12.4 in Molles 2006

Life History Patterns

B) Adult Survival and Reproductive Allocation

LIFE HISTORY CHARACTERISTICS

12

Fig. 12.13 in Molles 2006

Life History Patterns

Fig. 12.15 in Molles 2006

24

Life History Classification

3

4

Age at first Reproduction: 3-4 years

Age at First Reproduction:7 years

REPRODUCTION

REPRODUCTION

GROWTH RATE

8

COMPETETIVE ABILITY

5

6

LIFESPAN

Available Energy is Limited

Table 12.1 in Molles 2006

r versus K Selection

R selected K selected

“Small and Fast” “Large and Slow”

• MacArthur and Wilson 1967 (Birds, Insects)

• Pianka 1970, 1972 (Lizards)

“Frequent Disturbance” “Infrequent Disturbance”