Sara Garnett KBS K12 Summer Institute June 29 2012 Agenda Introduction to broader questions Game rules Play game Compile data and draw conclusions Followup discussion Competition Central to evolution by natural selection ID: 1018659
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1. Cannibalism: is it ever a good idea?Sara GarnettKBS K-12 Summer InstituteJune 29, 2012
2. AgendaIntroduction to broader questionsGame rulesPlay gameCompile data and draw conclusionsFollow-up discussion
3. CompetitionCentral to evolution by natural selection
4. Explaining Altruism?Some behavior seems unexpected if only individual survival and reproduction mattersKin selection helping relatives can benefit individual depending on circumstances
5. Why Cannibalism?Straightforward costs and benefits as behavioral strategy – what are some?
6. Costs and Benefits of CannibalismBenefitsProvides cannibal with meal Eliminates potential competitorCostsHigher risk of injury if more evenly matchedMay increase risk of diseaseOther indirect costs?
7. Spadefoot Toads
8. Spadefoot Toads
9. Basic Game RulesSeveral resources in “desert pond”You will be a tadpole from one familyOne minute to forage using stirrers and cup15 food items necessary to surviveSeveral rounds to simulate different conditions
10. Resources in EnvironmentPlant detritus (“general” food resource)Tadpoles from three families
11. Game RoundsRound One: Compete for general food on volleyball courtRound Two: Compete for resources on volleyball court using family strategyRound Three: Compete for resources on half of volleyball court using family strategy
12. Compiling Data (Rounds 2 and 3)Group Member# General Resources Eaten# Green Tadpoles Eaten# Red Tadpoles Eaten# Blue Tadpoles EatenTotal Resources Eaten
13. Off to the “pond!”
14. Discussion QuestionsCompare the results for rounds 2 and 3. Give a brief description of the patterns and propose an explanation for the results.Do any of the results surprise you? Why might this be?
15. Discussion QuestionsDid your individual success always correlate with family success? What does this tell you about evolution by natural selection?
16. Discussion QuestionsWhat sorts of traits or behaviors would you expect to see in species that tend to be cannibals? Why might these be useful?
17. Study ResultsCarnivore tadpoles spend less time around siblings than omnivoresCarnivores taste tadpoles and tend to release siblingsCarnivores prefer to consume non-siblings if given a choicePreference is weaker with increased hunger
18. Other Cannibalism Studies
19. Any questions?