WEEK 4 Jan 29 and Individual learning and how it interacts wit h nat ural select ion

Transcription

1 th th WEEK 4 Jan 29 and Individual learning and how it interacts wit h nat ural select ion Raghav Rajan Bio 335 Animal Behavior Jan 30th

2 Cent ral quest ion of animal behavior Why do animals behave t hey do? Proximate mechanisms Ult imate mechanisms Does it give t hem any advantage? Nat ural select ion works on variat ion present in t he populat ion Each animal is dif f erent f rom t he ot her An animal can also learn new t hings and become dif f erent f rom t he ot hers 2

3 How do animals learn? Learning f rom a single st imulus experience Sensit izat ion Habit uat ion Pavlovian condit ioning Inst rumental or operant condit ionning 3

4 Why do animals learn? Let us assume t hat learning is also anot her behavioral t rait Learning is also an adaptat ion Does it provide some survival or reproduct ive advantage? If yes, t hen potent ially nat ural select ion can work on t he abilit y to learn In ot her words, lets look at t heories of evolut ion of learning 4

5 Theories about evolut ion of learning Wit hin species st udies Populat ion comparisons Theories about evolut ion of learning in dif f erent environments 5

6 Wit hin species st udies Pavlov, Skinner, etc. Did not consider nat ural environment of animal Believed t hat all animals learn in t he same way Is t his t rue? What if nat ural select ion has worked on t he abilit y to learn? Individuals who learn appropriate cues usef ul in t heir specif ic environment nat ural select ion should f avour t hese individuals, right? 6

7 Garcia and colleagues experiments wit h rat s Rat s learn t o associat e only cert ain cues wit h cert ain behavioral out comes Maybe due t o behavioral relevance Also, learning occurs even when nausea occurs 75 mins af t er drinking wat er 7

8 Populat ion st udies Comparing individuals f rom dif f erent populat ions of same species Are t hey similar or dif f erent depending on t heir ecology, etc. 8

9 Zenaida dove populat ions in Barbados Group living populat ions 9 kms away solitary living doves Ecological condit ions should be similar? Doves f rom bot h groups brought t o t he lab were put on task t hat required pulling a ring to open a drawer to get f ood 9

10 Group living doves perf orm t his task better Improved learning Could be because of environment dif f erences Or nat ural select ion had made group living doves learn better 10

11 Anot her example of looking at dif f erent populat ions of t he same species St icklebacks f rom t wo dif f erent environments a high predat ion and low predat ion environment Fishes f rom bot h environments were raised in t he lab wit h no exposure to predators Are t heir ant i-predator st rategies dif f erent? Exposed f ishes to f ood Then simulated a heron attack and looked at how long f ishes took to avoid predat ion zone (also f ood zone) 11

12 High predat ion locale f ishes learnt f aster No dif f erences in f ood associat ion behavior No dif f erences in environment al condit ions 12

13 David St ephens' model f or evolut ion of learning Assumes t here is some cost associated wit h learning as against passing on a f ixed t rait 13

14 What animals learn... locat ion of home Locat ion of home learning to associate dif f erent cues wit h places Salmon use odor cues to learn about t heir home st reams 14

15 What animals learn... locat ion of mat es Learning about mates Learning t he locat ion of a mate may be related to parental care If only f emales provide parental care, t hen males should be better at learning t he locat ion of f emales Gourami (equal) and Japanese quail (only f emale) 15

16 What animals learn... who is relat ed and who is not? Learning who is kin May give reproduct ive advantage (inclusive f it ness) May lead to alt ruism, co-operat ive behavior 16

17 What animals learn... aggression Learning about aggression Blue gouramis can be t rained to associate light wit h int ruder Light cue is enough to make t hem increase aggression 17

18 What animals learn... aggression Trained males win more f ights Winner and loser ef f ects 18

19 Why do animals learn? Let us assume t hat learning is also anot her behavioral t rait Learning is also an adaptat ion Does it provide some survival or reproduct ive advantage? If yes, t hen potent ially nat ural select ion can work on t he abilit y to learn 19