1. Behavioral Biology Class 19

2. Behavior  What do you understand by behavior?  Learning  Animal cognition  Migratory behavior  Ecology  Reproduction

3. 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

4.  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 ((experience)  Nature (instinct) or nurture (experience) Approaches

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

6. 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

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

8. 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 in humans, Behavioral Genetics

9. 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

10.  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 Learning

11.  Classical conditioning: the paired presentation of two different kinds of stimuli with an association formed between them ◦ Ivan Pavlov: ◦ 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

12.  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 Learning: Operant conditioning

13. Development of Behavior  Parent-offspring interactions influence cognition and behavior  Imprinting:  Imprinting: formation of social attachment to other individuals or develop preferences that will influence behavior later in life  Filial imprinting:  Filial imprinting: attachment between parents and offspring Konrad Lorenz Noble Price 1973

14.  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 critical period in development ◦ Can not learn the song unless they hear it at a critical period in development Development of Behavior

15. Animal Cognition: Animal Cognition: What type of behavior demonstrates cognition-thinking?  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

16. 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 Migration involves population moving large distances: Monarch butterflies fly from North America to Mexico

17.  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 Orientation and Migratory Behavior

18. 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 behavior of one individual releases a behavior by another individual ◦ Stimulus-response chain: behavior of one individual releases a behavior by another individual

19. 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 Communication

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

21.  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 Communication

22.  Behavioral ecology: study of how natural selection shapes behavior ◦ Adaptive significance of behavior ◦ Reproductive success, fitness  Questions asked ◦ Is behavior adaptive ◦ How is it adaptive  Enhance energy intake, increase mating success, decrease predation Behavioral Ecology

23.  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 Behavioral Ecology Nobel Price 1973- shared with Lorenz Focus on: Development Physiological basis Function: including evolutionary significance

24. Foraging behavior can directly influence individual fitness  Foraging involves a trade-off between food’s energy content and the cost of obtaining the food  Optimal foraging theory: natural selection favors individuals whose foraging behavior is energetically efficient Behavioral Ecology Optimal foraging assumes that: Behavior maximizes energy Behavior maximizes energy acquisition if the increased energy reserves lead to increases in reproductive success i.e. Avoid predators, Find mates Optimal behavior has evolved by natural selection

25. Sexual Selection  Reproductive strategies:  decisions about mating ◦ How many mates to have ◦ How much time devoted to rearing offspring ◦ How much energy devoted to rearing offspring  Evolved partly in response to cost of reproduction

26.  Mating systems reflect adaptations for reproductive success  Energy costs, food resources, nest sites, distribution of opposite sex  Mating systems ◦ Monogamy: one male one female ◦ Polygyny: one male many females ◦ Polyandry: one female many males Sexual Selection

27.  Altruism: the performance of an action that benefits another individual at a cost to the actor  Question: if altruism imposes a cost to an individual, how could an allele be favored by natural selection?  Group selection: rare ◦ Among groups: leads to a decrease in allele’s frequency ◦ Within groups: may favor the allele Altruism

28.  Society: a group of organisms of the same species that are organized in a cooperative manner  Advantages ◦ Kin selection: greater odds of alleles surviving in the gene pool ◦ Greater protection from predators ◦ Increase feeding and mating success Social Systems