Transcript Winemiller and Rose

Chapter 8: Life history patterns
8.1 Sexual or asexual reproduction
8.2 Sexual reproduction takes a variety of forms
Simultaneous hermaphrodites
Sex reversal
8.3 Mating system: Polygyny 一夫多妻
Polyandry 一妻多夫
9.4 Acquisition of a mate involves sexual selection
Intrasexual selection (male to male competition)
Exaggerated secondary sexual characteristics
Intersexual selection: Handicapped hypothesis
A case study on tradeoff of reproductive traits
Tradeoffs between reproduction and survival
Females prefer individuals with long sword
Courtship
swimming
Routine
swimming
Fishes with long sword spend more energy to swim
8.6 Organisms budget time and energy to
reproduction
• Principle of Allocation: If organisms use
energy for one function such as growth, the
amount of energy available for other functions
is reduced.
– Leads to trade-offs between functions such
as number and size of offspring.
– Reproductive effort: time and energy
allocated to reproduction
Tradeoff between growth and reproduction
Interpreting trade-offs
8.7 Species differ in the timing of reproduction
• Semelparity (part = born) 一次產
• Iteroparity 多產
8.7-Parental investment depends on the number and
size of young
• Altricial: born in a helpless condition and
require considerable parental care
• Precocial: born in a more advanced
stage of development and need less
parental care
8.9 Fecundity (生育) depends on age and size
Life time reproduction correlates with body weight
Individuals smaller than 300 g unable to breed successfully
8.10 Food supply affects the production of young
Siblicide
8.11 Reproduction effort
may vary with latitudes
Food supply hypothesis
In temperate regions, mortality is
higher in the winter, which leaves
more food in the spring time
to use by breeding populations
8.13 Environmental conditions influence the evolution of life
history characteristics (Life history classification)
Spotted salamander
r selection
Redback salamander
K selection
r species
K species
Intrinsic rate of increase
high
low
Body size
small
large
Development
rapid
slow
Reproduction
early
late
Reproduction
semelparity iteroparity
Off spring
many, small few, large
Competitive ability
less
more
Opportunistic, Equilibrium,
and Periodic Life Histories
• Winemiller and Rose proposed new
classification scheme based on age of
reproductive maturity (), juvenile
survivorship (lx) and fecundity (mx).
– Opportunistic:
low lx - low mx - early 
– Equilibrium: high lx - low mx - late 
– Periodic:
low lx - high mx - late 
Opportunistic, Equilibrium,and Periodic Life
Histories
r species
K species
Grime’s model of life history traits of plants
A= annual herbs
B = Biennial herbs
P = Perennials
L = Lichens
T&S = Trees and shrubs
R = ruderals; C = competitive; S = stress-tolerants
(disturbance)
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