Another important way of thinking about life histories is bet hedging where variable environments don't allow for the evolution of one particular strategy. Consider the evolution of optimal clutch size ( how many eggs should I lay?). Again, the trade off between survivorship and reproduction may determine one clutch size, but in a variable environment , clutch sizes tend to be lower because there is an increased risk of losing an average investment in reproduction. A slightly smaller clutch can lead to a higher net reproductive rate (R o )because it can allow for more reproductive seasons than might be physiologically possible with larger clutch sizes. This argument applies iteroparous organisms ; the bet hedging in a semelparous orgnanism might involve hedging on how long to wait before reproducing because semelparous breeders will not have another clutch. Other alternative strategies for dealing with spatial and temporal heterogeneity Dormancy (wait out the bad times; seeds are good life history strategy
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This note was uploaded on 11/05/2011 for the course BIOLOGY MCB2010 taught by Professor Jessicadigirolamo during the Fall '10 term at Broward College.