130 likes | 242 Views
Application of Options Theory: Reproductive Strategies Based on Costs. Comparison of Organisms Relative to Size and Time to Maturity:. Smallest / Least time To Maturity. Largest / Longest time to Maturity. Relative to all Organism. What does this mean?.
E N D
Application of Options Theory:Reproductive Strategies Based on Costs
Comparison of Organisms Relative to Size and Time to Maturity: Smallest / Least time To Maturity Largest / Longest time to Maturity Relative to all Organism
What does this mean? Is there a correlation between the relative size of the organism and it’s strategy for producing offspring? • R-selection strategy • Characterized by strong variability in population size, tendency for high fertility • K-selection strategy • Near constant population size, slow development, delayed reproduction, and single broodedness Why do organisms choose one over the other?
Reasons Can be found in Costs Due to limited resources, parents must consider the costs associated with producing offspring. Costs can be expressed in terms of: • Resources (R) • include food & shelter • Time (T) • term of pregnancy, raising young, opportunity cost • Cognitive Development (C) • survival skills (hunting), identify & avoid predators
Cost of Producing Offspring Expressing Fixed Cost (FC) as a function of the individual costs components, we have: FC = R + T + C
Reasons for Asexual and Sexual Reproduction in Terms of Cost Asexual reproduction (r-selection strategy) less costly compared to sexual reproduction, can afford high variability/volatility in survival rate of offspring from large population Sexual reproduction (k-selection strategy), cost intensive to parents, increased likelihood of survival for trade-off in lower number of offspring produced
Asexual vs. Sexual Reproduction Meiosis (Sexual) Mitosis (Asexual) DNA double Helix uncoils Splitting chromosome Pair into two separate strands After fertilization, chromosomes recombine 2 daughter cells 4 gametes
Output to Different Levels of Fixed Costs Where output is measured as the number of offspring successful produced: Fixed Costs Rate of Success Offspring
Phenomenon also seen in Allometry In its most general sense, allometry is the study of size and it’s consequence. Source: The Allometry of Growth and Reproduction
Similarity with Options Theory Rate of Return Output Low Fixed Cost High Fixed Cost
Uncertainty and Costs High Volatility Variable Costs Low Volatility Level of Fixed Costs
Affects of Uncertainty on Reproduction High Volatility Low Volatility Death Rate As Level of Fixed Costs Increases Level of Fixed Costs
Uncertainty and the Value of the Option to Reproduce Referring to the options theory where the: dS =rdt + dz S Where (S) denotes the growth rate of the species (r) is the growth term associated with the rate of success in producing offspring, and () is the volatility in offspring survival. This shows that the growth of the species is dependent on: -the increase of (r), and decrease of ()