LIFE HISTORY STRATEGY
Jan 20, 2016
LIFE HISTORY STRATEGY
Life History Strategy
A suite of traits that improve an individual's chances of surviving and
reproducing in a particular environment
1. Energy commited to one function is not available for others.
2. Every evolutionary ‘choice’ has costs and benefits
3. Every organism represents a compromise of a number of evolutionary ‘choices’
COST/BENEFIT ANALYSIS
Macarthur and Wilson (‘70’s) - Theory of Island Biogeography
r strategists K strategists
Equilibrium-slower colonizing, slow growth
Opportunistic-rapidly colonizing, fast growth
r - selected K - selected
Climate
Mortality
Population Size
Community Characteristics
Lifespan
Individual Attributes
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality
Population Size
Community Characteristics
Lifespan
Individual Attributes
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size
Community Characteristics
Lifespan
Individual Attributes
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size Variable, below K Consistent
Community Characteristics
Lifespan
Individual Attributes
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size Variable, below K Consistent
Community CharacteristicsFew species,
recolonizationMore species, no
recolonization
Lifespan
Individual Attributes
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size Variable, below K Consistent
Community CharacteristicsFew species,
recolonizationMore species, no
recolonization
Lifespan Short Long
Individual Attributes
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size Variable, below K Consistent
Community CharacteristicsFew species,
recolonizationMore species, no
recolonization
Lifespan Short Long
Individual AttributesRapid development, early reproduction, high rate of increase, small body size
Slow development, late reproduction, low rate of increase, larger body size
Allocation of Energy
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size Variable, below K Consistent
Community CharacteristicsFew species,
recolonizationMore species, no
recolonization
Lifespan Short Long
Individual AttributesRapid development, early reproduction, high rate of increase, small body size
Slow development, late reproduction, low rate of increase, larger body size
Allocation of Energy Greater % to reproductionGreater % to growth and
maintenance
Attributes of r and K - selected organisms
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival Density dependent,
uncertain juvenile survival
Population Size Variable, below K Consistent
Community CharacteristicsFew species,
recolonizationMore species, no
recolonization
Lifespan Short Long
Individual AttributesRapid development, early reproduction, high rate of increase, small body size
Slow development, late reproduction, low rate of increase, larger body size
Allocation of EnergyGreater % to reproduction
Greater % to growth and maintenance
Attributes of r and K - selected organisms
Productivity
r - selected K - selected
Climate Variable, unpredictible Consistent, predictible
Mortality Density independent,
uncertain adult survival
Density dependent, uncertain juvenile
survival
Population Size Variable, below K Consistent
Community CharacteristicsFew species,
recolonizationMore species, no
recolonization
Lifespan Short Long
Individual AttributesRapid development, early reproduction, high rate of increase, small body size
Slow development, late reproduction, low rate of increase, larger body size
Allocation of EnergyGreater % to reproduction
Greater % to growth and maintenance
Attributes of r and K - selected organisms
Productivity Efficiency
r-strategist K-strategist
r - K continuum
r-strategist K-strategist
Frequent disturbance Less frequent disturbance
r - K continuum
Death
recruitment
Aclonal Life History
Sexual reproduction
Death
recruitment
Clonal Life History
FissionFissionFission
Sexual reproduction
Fertilization Patterns
1. External (no copulation)
Fertilization Patterns
1. External (no copulation)
Problems
Gamete output
Synchrony
Gamete dispersal
Gamete dilution
Fertilization Patterns
1. External (no copulation)
Problems
Gamete output
Synchrony
Gamete dispersal
Gamete dilution
% success
Distance between individuals
0.5 m
100
Fertilization Patterns
1. External (no copulation)
Allee Effect
Reproductiverate
Number or Density
Fertilization Patterns
2. Internal (no copulation)
For oyster spawning video: www.umces.edu/ 2002Session/oyster.html
Fertilization Patterns
2. Internal (copulation)