Critical thinking questions 1. what is the difference between weather and climate in terms of temporal variation? 2. how could spatial heterogeneity be perceived by an organism as temporal heterogeneity? 3. why do we have to consider the mean fitness across all environments when evaluating whether evolving a phenotypically plastic genotype will be favored over a non-plastic genotype? 4. how would the presence of unreliable environmental cues affect the evolution of phenotypically plastic responses to environmental variation? 5. would the frequency of experiencing predator versus no-predator environments affect the evolution of phenotypically plastic traits? 6. if predators reduce prey abundance to very low levels, how might variable predator environments affect the evolution of flexible mating strategies? 7. if a plant can improve its ability to obtain water by growing more roots, why shouldn't the plant always grow more roots? 8. how could you experimentally determine whether migrating birds use day length or temperature as an environmental cue for migration? 9. what is the relationship between correlation and causation? 10. when determining whether to feed on small, medium, or large prey, why should predators evaluate both the energy obtained from each prey item, the abundance of each prey item, and the handling time of each prey item? 7