Life History Strategy
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LIFE HISTORY STRATEGY Life History Strategy A suite of traits that improve an individual's chances of surviving and reproducing in a particular environment COST/BENEFIT ANALYSIS 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’ Macarthur and Wilson (‘70’s) - Theory of Island Biogeography r strategists Opportunistic -rapidly colonizing, fast growth K strategists Equilibrium -slower colonizing, slow growth Attributes of r and K - selected organisms r - selected Climate Mortality Population Size Community Characteristics Lifespan Individual Attributes Allocation of Energy K - selected Attributes of r and K - selected organisms Climate Mortality Population Size Community Characteristics Lifespan Individual Attributes Allocation of Energy r - selected K - selected Variable, unpredictible Consistent, predictible 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 Characteristics Few species, recolonization More 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 Characteristics Few species, recolonization More 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 Characteristics Few species, recolonization More species, no recolonization Lifespan Short Long Individual Attributes Rapid 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 Characteristics Few species, recolonization More species, no recolonization Lifespan Short Long Individual Attributes Rapid 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 reproduction Greater % 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 Characteristics Few species, recolonization More species, no recolonization Lifespan Short Long Individual Attributes Rapid 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 reproduction Greater % to growth and maintenance Productivity 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 Few species, recolonization More species, no recolonization Lifespan Short Long Individual Attributes Rapid 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 reproduction Greater % to growth and maintenance Productivity Efficiency r - K continuum r-strategist K-strategist r - K continuum r-strategist Frequent disturbance K-strategist Less frequent disturbance Aclonal Life History recruitment Sexual reproduction Death Clonal Life History Sexual reproduction recruitment Fission Fission Fission Death 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 100 % success Gamete dispersal Gamete dilution 0.5 m Distance between individuals Fertilization Patterns 1. External (no copulation) Allee Effect Reproductive rate Number or Density Fertilization Patterns 2. Internal (no copulation) For oyster spawning video: www.umces.edu/ 2002Session/oyster.html Fertilization Patterns 2. Internal (copulation)
