trade-off: when a choice must be made between two, or multiple things that are either incompatible or in shortage, then an increase in one thing might lead to a decrease in another. In the evolutionary context, the currency is survival/reproduction.
17 octubre, 2023
Evolutionary trade-offs
Evolutionary trade-offs
One-trait trade-off - Result of an opposing selection on that one trait via a different environment or through a limiting resource.
Ex: the head of the newborn baby - the bigger the better for development but the more risky at the labour.
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Evolutionary trade-offs
Multiple-trait trade-off - Having a single resource where it is impossible to use this resource to increase more than one trait at once.
Ex: in the howler monkey, the bigger a male’s vocal organ/louder the roar, the smaller their testes/less sperm production.
What is optimal behaviour/strategy?
DEF: an action that maximizes the difference between the costs and benefits (benefits > costs); generated by trade-offs
Three variables in optimality models of behaviour:
- constraints (various ecological/biological limitations)
- currency (to be maximized)
- decision (evolutionary output),
Optization in practice
1 Define the behaviour -> f(x | c(x))
2 Find the function extremum
3 Interpret it and conlcude
Optization in practice
Pareto front
The boxed points represent feasible choices, and smaller values are preferred to larger ones. Point C is not on the Pareto frontier because it is dominated by both point A and point B. Points A and B are not strictly dominated by any other, and hence lie on the frontier.
Shoval, O., H. Sheftel, G. Shinar, Y. Hart, O. Ramote, A. Mayo, E. Dekel, K. Kavanagh, and U. Alon (2012). Evolutionary trade-offs, pareto optimality, and the geometry of phenotype space. Science 336:1157–1160.
Optimal foraging theory
Situation:
- discrete patches of resources (eg. food)
- the patches separated by resource-free space
- diminishing returns (MVT: Marginal Value Theorem)
- decision to be made: GUT/GUP (Giving-Up Time/Giving-UP resource Density)
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Optimal foraging theory
Ex: foraging in fruit orchard
Optimal foraging theory
Ex: birds and snails - empirical value 5.2 (Zach 1979)
Optimal foraging theory
Ex: birds and snails - empirical value 5.2 (Zach 1979)
Optimal model in another situation
Ex: copulating flies - empirical value: 35 min, 80% eggs
Optimal model in another situation
Ex: copulating flies - empirical value: 35 min, 80% eggs
Model type: Marginal Value Theorem (MVT)
References
Agrawal AA et al (2010) Tradeoffs and Negative Correlationsin Evolutionary Ecology BT - Evolution
Since Darwin. Evol Since Darwin 243–268
Conner JK (2002) Trade-Offs in Evolutionary Ecology. Ecology 83:2356–2357
Dunn JC et al (2015) Evolutionary trade-off between vocal tract and testes dimensions in howler monkeys. Curr Biol 25:2839–2844
Garland T (1995) Trade-offs. Curr Biol 24:R60–R61
Kazancioǧlu E, Alonzo SH (2012) The evolution of optimal female mating rate changes the coevolutionary dynamics of female resistance and male persistence. Philos Trans R Soc B Biol Sci 367:2339–2347
Zach R (1979) Shell dropping:decision-making and optimal foraging in northwestern crows. Behavior 68:106–117
Shoval, O., H. Sheftel, G. Shinar, Y. Hart, O. Ramote, A. Mayo, E. Dekel, K. Kavanagh, and U. Alon (2012). Evolutionary trade-offs, pareto optimality, and the geometry of phenotype space. Science 336:1157–1160.