3/12/15&1&Animal&Behavior&Gene 2 Trait 1 Gene 1 Gene 3 Environment The Nature vs. Nurture Fallacy Nothing&can&ever&be&purely&environmental&Nothing&can&ever&be&purely&gene;cally&determined&&&Environment behavior)is)the)product)of)thousands)of)gene3environmental)interac6ons)development)of)every)a8ribute)of)every)living)thing)requires)the)informa6on)contained)in)a)large)number)of)genes))Nature&–&causa;on&(genes)&=&“ins;ncts”&&&Nurture&–&development&(environment)&=&“learning”&3/12/15&2&Behaviors&evolve&via&the&same&mechanisms&as&physical&characteris;cs&Trait&1.&Varia;on&in&trait&&e.g.,&likelihood&of&fleeing&Fitness&Trait&2.&&Selec6on&=&NonLrandom,&differen;al&reproduc;on&3.&Trait&is&heritable&à&distribu;on&of&trait&shiNs&Communica;on&The&transfer&of&informa;on&through&the&environment&by&senders&that&influences&the&behavior&of&receivers&by&the&use&of&evolved&signals)&Signal&Types:&&&Visual,&Auditory,&Electrical,&Chemical,&Mechanical&3/12/15&3&Signal&=&a&trait&that&has&evolved&through&natural&selec;on&because&it&has&enabled&its&bearers&to&convey&informa;on&to&other&organisms.&Diagram of simple communication system Sender Receiver Environment Informa6on)Change&in&behavior&3/12/15&4&Why&communicate?&• Benefits&– Finding&mates&– Finding&food&– Avoiding&predators&&• Costs&– More&vulnerable&to&preda;on/aXack&– Physiological&costs&– Decreased&foraging&Communica;on&with&Predators&à&Defenses&• Behaviors&– Displays&– Camouflage&to&avoid&detec;on&• Mechanical&(Example:&spines)&Monarch&BuXerfly&Coral&Snake&• Aposema6c)colora6on)=&Warning!&signals&3/12/15&5&Warning&colora;on&and&predator&learning&Monarchs&sequester&toxic&compounds&from&milkweed&plants.&Naive&Blue&Jays&vomit&aNer&ea;ng&a&monarch&&&à&Learn&to&avoid&any&buXerfly&that&resembles&a&monarch&&But&geang&eaten&doesn’t&improve&fitness&(huge&cost)!&&&How&could&this&colora;on&evolve&(what’s&the&benefit)?&Hypotheses:&• Lower&mortality&of&close&rela;ves&or&offspring&• Not&always&fatal&3/12/15&6&Mimicry)à&Selec;ve&pressure&for&similar&color&paXerns&Mon&Monarch&BuXerfly&Toxic&model&Viceroy&BuXerfly&NonLtoxic&mimic&Eastern&Coral&Snake&Toxic&model&Scarlet&King&Snake&NonLtoxic&mimic&Sexual&Dimorphism&Male&&&Female&of&the&species&look&drama;cally&different&3/12/15&7&Sexual&Selec;on&Intrasexual&Selec;on&à&Male&compete&directly&with&each&other&Intersexual&Selec;on&à&Males&compete&for&female&aXen;on&Courtship&Displays&• Species&specific&&• Highly&repeatable&&• Similar&between&individuals&• Func;on&as&signals&• Favored&via&Natural&Selec;on&3/12/15&8&Female&Mate&Choice&=&Good&genes&1.&&Must&be&varia;on&in&male&quality&2. Some&correla;on&between&male&trait&and&quality&– Parasite&resistance;&Strength;&Compe;;ve&ability;&etc.&3.&&Females&who&show&preference&have&beXer&offspring&&Runaway&Selec;on&As&;me&goes&on…&– Male&trait&evolves&through&sexual&selec;on&by&female&– Female&preference&evolves&because&it&becomes&linked&to&male&trait&–
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