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The Evolution of Dilution. Andrew Paitsel Allen Patton. Co-evolutionary Arms Race. Predator/Prey Survival Adaptions Faster prey = faster predators Better eyesight = better camoflauge Other Survival Adaptations -Warning calls -Mobbing behaviors -Traveling in herds (Dilution Effect). - PowerPoint PPT Presentation
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The Evolution of Dilution Andrew PaitselAllen Patton
Co-evolutionary Arms Race Predator/Prey Survival AdaptionsFaster prey = faster predatorsBetter eyesight = better camoflauge
Other Survival Adaptations-Warning calls-Mobbing behaviors-Traveling in herds (Dilution Effect)
Questions to AddressWhat is the Dilution Effect?What are the advantages/disadvantages?What species has practiced this trait?
What is the Selfish Herd theory?How does it affect the population?
What other ways do animals behave due to predation?
Dilution Effectthe assumption that everyone has an equal chance of survival while in large groups due to the fact that no individual is being singled out by a predator.
Advantages More eyes watching out for predatorsPredator not being able to choose the easiest preyPrey species spend more time foraging instead of scanning for predators
The frequency of scans as a result of relative dangerBednekoff et al, 1998.
DisadvantagesMore likely to be seen by predatorsMore competition over resourcesMore competition over mate selection
Examples
Stotting
StottingAlarm signal hypothesisSocial cohesion hypothesisConfusion effect hypothesisPursuit deterrence hypothesis
Disadvantages of StottingTime Cost
Energy Cost
Survivorship Cost
The Selfish HerdCompetition for safer positioning within the herd. Middle position has overall higher survival probability that individuals on the outer partsIncreasing your overall fitness at the expense of others
Future ResearchDetermine if traveling in herds is a learned or genetic traitLook into how predators counteract the Dilution EffectIs stotting a learned or inherited trait
Continue to evolve until someone gets the upper hand
ReferencesAlcock J. 2005. Animal Behavior: An Evolutionary Approach. Sinauer Associates, Inc. 8:176-199Bednekoff P.A., Lima S.L. 1998 Re-examining safety in numbers: interactions between risk dilution and collective detection depend upon predator targeting behaviour. The Royal Society. 265:2021-2026Caro T.M. 1986. The Functions of Stotting in Thomsons Gazelles: some tests of the predictions. Animal Behaviour. 34(3):663-684Caro T.M. 1985. Functions of Stotting. Animal Behaviour. 34(3):649-661Cresswell W., Jakobsson S., Kaby U., Lind J., Quinn J.L. 2003. Animal Behaviour. 66:643-648Garay J. 2008 Cooperation in defence against a predator. Journal of Theoretical Biology 257:45-51
References Cont.Pictureshttp://static.howstuffworks.com/gif/gazelle-body-language-1.jpghttp://www.teameveresttravel.com/main/images/stories//InternationalVacations/gallery-africa/Day3/Herds_Maasai_Mara.jpghttp://images.google.com/imgres?imgurl=http://www.travelphotos.in/thumbs/lrg-106-img_3500_cheetah_brothers.jpg&imgrefurl=http://www.serengeti.in/index.php%3Fcat%3D102&usg=__-6gpONj-zFPa-tqP3oSTLkZk2s0=&h=459&w=400&sz=76&hl=en&start=28&tbnid=ltIijJbwd6BUDM:&tbnh=128&tbnw=112&prev=/images%3Fq%3DCheetah%2Bvs.%2Bherd%26gbv%3D2%26ndsp%3D18%26hl%3Den%26sa%3DN%26start%3D18http://images.google.com/imgres?imgurl=http://scienceblogs.com/clock/upload/2006/06/zebra%2520lion.jpeg&imgrefurl=http://scienceblogs.com/clock/2006/06/bio101_lecture_7_physiology_co_1.php&usg=__4u3AfFA8W3wSxJwtO7X3est7kng=&h=323&w=448&sz=102&hl=en&start=2&tbnid=XCMpf2ZkAhcQLM:&tbnh=92&tbnw=127&prev=/images%3Fq%3DZebra%26gbv%3D2%26hl%3Denhttp://images.google.com/imgres?imgurl=http://lh4.ggpht.com/_ntEIaR868hs/RpwQkCU_I0I/AAAAAAAAA3w/nN0Qbe1dr3o/Africa-227.JPG&imgrefurl=http://picasaweb.google.com/lh/photo/O9qg8k9BUkfv5fxiJgZY6g&usg=__qmMBImFnwIvSowsez5V1Ayeaaig=&h=1068&w=1600&sz=11&hl=en&start=3&tbnid=CbmEpymRX0P63M:&tbnh=100&tbnw=150&prev=/images%3Fq%3DWildabeest%2Bherd%26gbv%3D2%26hl%3Den
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