Behavioral Biology Chapter 54

1. Behavioral BiologyChapter 54

2. Approaches • Behavior:the way an animal responds to stimulus in its environment • Two components of behavior • Immediate cause • Evolutionary origin • Proximate causation:“how” of behavior • Measure: hormone level - testosterone • Impulse of nerve signal

3. Approaches • Ultimate causation: “why” of behavior • Determine how behavior influences reproductive success or survival • Controversy: • Is behavior determined by individual’s genes • Or by learning and experience • Nature or nurture

4. Approaches • Innate behavior: instinctive, does not require learning • Preset paths in nervous system • Genetic: fixed action pattern Example: goose replacing an egg from her nest

5. Approaches • Egg retrieval behavior is triggered by a sign stimulus • Innate releasing mechanism or fixed action pattern is the stereotyped act • Not very specific: anything round will trigger the goose’s reaction • Once pattern begins, it goes to completion; even if the egg is removed

6. Approaches • Male stickleback fish will attack anything with a red underside • Does not need to be a fish • Supernormal stimuli: given a choice: animals respond to a larger stimuli over a normal size stimuli

7. Behavioral Genetics • Artificial selection data has shown that behavioral differences among individuals often result from genetic differences • Genetics of learning

8. Behavioral Genetics Human twin study • Identical twins: identical genetically • 50 sets, twins raised separately • Similarity in personality, temperament, leisure time activities • Indicates that genetics plays a role in determining behavior even in humans

9. Behavioral Genetics • Single gene: Drosophila • Alternative alleles for feeding behavior as larvae • One type moves around to eat • Second type remain in same area to eat • Courtship behavior also affected by a mutation in a single gene

10. Behavioral Genetics • Mice: fosB gene • Determines whether female mice nurture their young • Both fosB alleles disabled: ignore young • Normal mothers: protective maternal behavior • Protein expressed by fosB activates other enzymes and genes that affect neural circuitry within the hypothalamus

11. Behavioral Genetics • fosB present: mother cares for her young • fosB absent: young are ignored and eventually die

12. Behavioral Genetics (Cont.)

13. Behavioral Genetics • Prairie voles are monogamous • Montane voles mate and do not work together to raise young • Different response to oxytocin and vasopressin • Peptide receptors different

14. Behavioral Genetics (Cont.)

15. Learning • Learning: altered behavior as a result of previous experiences • Nonassociative learning: does not require an animal to form an association between two stimuli or between a stimulus and response • Habituation: decrease in response to a repeated stimulus • No positive or negative consequences

16. Learning • Associative learning: association between two stimuli or between a stimulus and a response • Conditioned behavior through association • Two major types: • Classical conditioning • Operant conditioning • Differ in the way associations are established

17. Learning Associative learning is involved in predator-prey interactions: after being stung the toad learns not to eat bumblebees.

18. Learning (Cont.) Associative learning is involved in predator-prey interactions: after being stung the toad learns not to eat bumblebees.

19. Classical conditioning: the paired presentation of two different kinds of stimuli with an association formed between them • Pavlovian conditioning • Unconditioned stimulus: meat • Unconditioned response: salivating • Conditioned stimulus: bell ringing • Conditioned response: After time, the dog salivates with only the ringing of the bell

20. Learning • Operant conditioning: animal learns to associate its behavior response with a reward or punishment • B.F. Skinner • Trial and error learning • Today it is believed that instinct guides learning by determining what type of information can be learned through conditioning

21. Learning • Instinct and learning • Innate predispositions toward forming certain associations • Pigeons can learn to associate food with colors, but not with sound • Learning is possible only within the boundaries set by instinct • In nature, adaptation by learning is important to survival

22. Learning • Clark’s nutcracker can remember the locations of up to 2000 seed caches months after hiding them • Uses spatial memory

23. Development of Behavior • Parent-offspring interactions influence cognition and behavior • Imprinting: formation of social attachment to other individuals or develop preferences that will influence behavior later in life • Filial imprinting: attachment between parents and offspring • Konrad Lorenz

24. Development of Behavior • Goslings follow Konrad Lorenz as if he were their mother • 1973 Nobel Prize

25. Development of Behavior • Instinct and learning may interact as behavior develops • White-crowned sparrow males sing species-specific courtship song during mating • Genetic template: innate program to learn the appropriate song • Can not learn the song unless they hear it at a critical period in development

26. Development of Behavior • Exposed to own species song during development • Not exposed to song

27. Development of Behavior • Cuckoos are raised by a different species • Learn their own song: innate

28. Animal Cognition • Do animals show cognitive behavior • What type of behavior demonstrates cognition? • Japanese macaques learned to wash sand off potatoes • Chimps pull the leaves of off a tree branch to use it as a tool for picking termites • Some birds learn to take off milk caps from bottles

29. Animal Cognition

30. Animal Cognition (Cont.)

31. Animal Cognition (Cont.)

32. Orientation and Migratory Behavior • Orientation: goal-oriented movements • Track stimuli in the environment • Homing instinct • Taxis: movement toward or away from a stimulus • Kineses: more or less active when stimulus intensity increases

33. Orientation and Migratory Behavior • Migration involves population moving large distances • Monarch butterflies fly from North America to Mexico

34. Orientation and Migratory Behavior It takes 2 - 5 generations for the migration

35. Orientation and Migratory Behavior Bobolinks have changed their migration by adding a new segment

36. Orientation and Migratory Behavior • Migrating animals must be capable of orientation and navigation • Navigation: the ability to set or adjust a bearing • Sun and stars: general direction • Earth’s magnetic field: specific path • Information from the stars overrides the magnetic information if they conflict

37. Orientation and Migratory Behavior Migratory behavior of starlings

38. Communication • Communication can play a key role in behaviors • Among members of the same species • Between species • Successful reproduction depends on appropriate signals and responses • Stimulus-response chain: behavior of one individual releases a behavior by another individual

40. Communication Long-distance communication • Pheromones: chemical messengers • Sex attractant • Males have sensory receptors • Some insect pheromones can be detected as far as 7km away • Acoustic signals • Vocal calls, wing clicking • Light signals: firefly

41. Communication Bioluminescent displays of lampyrid beetles are species-specific. Each number represents the flash pattern of a male of a different species

42. Communication Communication facilitates group living • Guards: set off an alarm call so group can seek shelter • Social insects produce pheromones that trigger attack behavior • Ants deposit trail pheromones between nest and food source

43. Communication The waggle dance of honeybees

44. Communication • James L. Gould devised an experiment to trick hive members into going in the wrong direction • Supported von Frisch’s explanation of the bees using the Sun as their reference position • Eliminated Wenner’s challenge that it was flower odor that drew the bees to the food location • Robot bees are now being used

45. Communication Primate language: Vocabulary to communicate identity of specific predators

46. Communication • Chimpanzees and gorillas can learn to recognize a large number of symbols and use them to communicate abstract concepts • Complexity of human language • Differences are superficial • 3000 languages draw from the same set of 40 consonant sounds

47. Communication • Signals vary in their degree of specificity • Level of specificity: relates to the function of a signal • Mark territories with pheromones • Species and other species specific • Pursuit-deterrent signals: predator has been seen and should not waste time chasing the prey

48. Communication Cleaner Fish. The grouper has entered the cleaner fish’s “station” and adopted a posture that allows the cleaner fish to enter the mouth and gills and feed on attached parasites

49. Behavioral Ecology • Niko Tinbergen divided the investigation of behavior into the study of • Development • Physiological basis • Function: including evolutionary significance

50. Behavioral Ecology • Evolutionary analysis: survival value of behavior • Tinbergen observed gull nestlings hatch and parents remove the shells of the eggs • Placed broken eggs by the nests • Predators (crows) found nests with broken eggs and ate the hatchlings • Nests without egg shells had less predation