Lecture 11 – 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 Energy committed to one function is not available for others.

COST/BENEFIT ANALYSIS Energy committed to one function is not available for others. 2. Every evolutionary ‘choice’ has costs and benefits Settles on wave exposed shore Costs Benefits -energy in holding on -less exposure to predators -restricted movement for food gathering -more food delivery -less energy directed to growth -size restriction

COST/BENEFIT ANALYSIS 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’ Periclimenes yucatanicus Colour - bright & obvious to predators - disruptive Hides in anemone – restricted foraging but has protection Exoskeleton – restricts movement but offers protection

Macarthur and Wilson (‘70’s) - Theory of Island Biogeography R.H. Macarthur Macarthur and Wilson (‘70’s) - Theory of Island Biogeography r strategists K strategists E.O. Wilson Opportunistic -rapidly colonizing, fast growth Equilibrium -slower colonizing, slow growth

Attributes of r and K - selected organisms r - selected K - selected Consistent, predictible Density dependent, uncertain juvenile survival Consistent More species, no recolonization Long Slow development, late reproduction, low rate of increase, larger body size Greater % to growth and maintenance Climate Variable, unpredictible Consistent, predictible Density independent, uncertain adult survival Density dependent, uncertain juvenile survival Mortality Variable, below K Consistent Population Size More species, no recolonization Community Characteristics Few species, recolonization Lifespan Short Long Rapid development, early reproduction, high rate of increase, small body size Slow development, late reproduction, low rate of increase, larger body size Individual Attributes Greater % to growth and maintenance Allocation of Energy Greater % to reproduction

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

Look at our original energy allocation graphs More r - like More K - like

r - K continuum r-strategist K-strategist Frequent disturbance Less frequent disturbance

Aclonal Life History recruitment Sexual reproduction Death

Clonal Life History recruitment Death Sexual reproduction Fission

Life history pattern -- a genetically inherited pattern of resource allocation to that optimizes the passing of genes to the next generation EGG AND SPERM PRODUCTION FERTILIZATION PATTERNS TYPES OF DEVELOPMENT LARVAL DISPERSAL STRATEGIES SETTLEMENT PATTERNS