Communication  The Evolution of Signals

Communication The Evolution of Signals PowerPoint PPT Presentation


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Communication The Evolution of Signals

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1. Communication & The Evolution of Signals NSF GK12 Workshop: May 9, 2009 Nancy Burley Professor of Ecology & Evolutionary Biology University of California, Irvine

3. Examples of “Why” Questions Warning calls in Belding’s ground squirrels Interspecific imitation of mating signals by female fireflies

4. (def.) Signal – a trait that has evolved through natural selection because it has enabled its bearers to convey information to other organisms. Communication involves transmission of signals, either in intraspecific or interspecific context.

6. Belding’s ground squirrels as example of intraspecific communication

7. Examples of Interspecific communication Trumpet creeper? hummingbird Viceroy?butterfly (example of Batesian mimicry, in which a palatable species possesses an evolved resemblance to a toxic species) Photuris ?? Photinus communication

9. Two kinds of messages Signals – messages that serve an evolved function (which benefits the sender and may or may not benefit receiver) Signs or cues – messages that do not an evolved function (including intercepted signals)

11. How do signals originate? agnolotti Bollywood Crunk Ginormous Gray literature IED Polyamory Nocebo Perfect storm Speed dating Mouse potato

13. (def.) Intention Movement: incidental movement that “gives away” what animal is about to do. Sky pointing: about to take flight. This bird displaying a highly stylized version of sky pointing that is exaggerated.

14. Sequence of signal evolution

16. Parent-offspring communication in herring gulls Adult herring gulls have a red spot on beak. When hatchlings peck it, parents stimulated to regurgitate food.

17. Tinbergen: chicks respond to spots of many colors & locations. Thus, any spot on parent beak might have triggered offspring reaction.

18. Sequence of signal evolution

19. Examples of signal evolution that capitalize on receiver biases Bittern on nest Frog with “eyes” on back Lattern bug Orchid False coral snake Cichlid “egg dummies”

20. Deceit vs honesty of signals Obviously-deceptive signals common in interspecific communication. In intraspecific communication, signal honesty may evolve, because receivers evaluate reliability of signals and favor those that are reliable (“honest advertisement”).

21. Honest Advertising Multiple stages of assessment vigor of ritualized displays multiple stages of testing, each one escalated e.g., red deer

22. Difficulty of predicting receiver bias and meaning of novel signal. Example: estrildine finches

23. Degree of honesty of signal may change over time Example: begging call loudness in nestling birds

24. Summary Clear thinking about animal communication enhances understanding of evolution. Unpredictability of evolution Constraints on evolutionary response Signals evolve to benefit their bearers, not a “species” or group of species. Communication is the use of evolved signals to manipulate or influence others of same or different species. Signals may be “honest” or “deceitful”. Dynamics differ between interspecific and intraspecific systems. Response to “receiver bias” is an important route for evolution of novel signals.

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