Study Documents Behavioral Biology

Behavioral Biology Study Documents What is Behavior? • • Behavior is what an animal does and how it does it. Ethology- is the study of how animals behave in their natural habitat. Mechanistic basis for behavior: • • Identify the stimuli that triggers the behavior or Study the psychological, neuronal, and hormonal changes that underlie the behavior E.g., MIGRATION Distribution & Migration Map of Pacific Golden Plover Proximate Cause • • External stimuli- changes in day length and temp Internal stimuli - hormone levels Ultimate Causation - addresses the evolutionary significance for a behavior and why natural selection favors this behavior. • • • Why did a behavior evolve? Is it adaptive? Does it contribute to reproductive success? Example: birds that migrate have a selective advantage over birds that don't/didn't, selected for over time, could be due to long term climate changes, glaciation, disease, taking advantage of food sources, etc. Practice and exercise may explain the ultimate bases of play Play as a behavior has no apparent external goal, but may facilitate social development or practice of certain behaviors and provide exercise. BEHAVIOR: A male stickleback fish attacks other male sticklebacks that invade its nesting territory. PROXIMATE CAUSE: The red belly of the intruding male acts as a sign stimulus that releases aggression in a male stickleback. ULTIMATE CAUSE: By chasing away other male sticklebacks, a male decreases the chance that eggs laid in his nesting territory will be fertilized by another male. Nature versus Nurture: Nature Behaviors are: • Innate • Hard-wired • Instinctual • Genetically determined Nurture Behaviors are: • Learned • Flexible • Not genetically determined Behavior results from both genes and environmental factors To some extent ALL behavior has a Genetic Basis • • • some is totally genetic - which implies heritable some is learned but relies ENTIRELY on genetically based mechanisms Genes code for RNA and proteins. They do not directly code for a behavior. In general, behavior is a response to some environmental stimulus Mixed-Up Brothers of Bogata Switched at birth! Two sets of identical twins were raised as two sets of Fraternal Twins. Innate Behaviors/ Instinct – inherited, highly stereotypes (same each time for many individuals) • • • • The behavior is performed correctly the 1st time without prior experience (not learned) Triggered by some external Sign Stimulus Once started, run to completion with no further input (FAP) Breeding crosses produce hybrid behaviors Categories of Innate behaviors • • • Directed Movement- Kinesis and Taxis Reflex: movement of a body part in response to stimulus Fixed Action Pattern (FAP) Directed Movements • Kinesis: simple change in activity or turning rate in response to a stimulus • Taxis: automatic movement, oriented movement +/- from stimulus (eg. phototaxis, chemotaxis, geotaxis) FAPs Stereotyped and often complex series of movements, response to a specific sign stimulus/ releaser, hardwired, however, not purely genetic as may improve with experience examples: • • courtship behavior rhythms - daily (circadian); annual (circannual) Fruit Fly Courtship Nobel Prize in Physiology or Medicine 1973 Herring gull experiment by Niko Tinbergen Releaser Stimuli- stimuli that release FAP E.g., Chick and red dot on gull parents beak triggers feeding response- parent regurgitates food Laysan albatross feeding chick Tinbergen: Male three-spined stickleback shows aggression at models with red undersides Lorenz: Egg rolling behavior in geese is a Fixed Action Pattern Learning Behavior is modified based on experience Categories: • • o o o • • Habituation Associative Learning Classical Conditioning Operant Conditioning Imprinting Latent Learning Insight Learning Habituation Decline in response to a harmless, repeated stimulus. Prevents animal from wasting energy/attention on irrelevant stimuli Associative Learning- Classical Conditioning Classical Conditioning - animal learns to perform an "old" response to a new stimulus • • Pavlov's dog - place dried meat powder in dog mouth - salivation - associate with bell - salivation to bell Stimulus first, behavior second Associative learning: Operant Conditioning. o This is called trial-and-error learning - an animal learns to associate one of its own behaviors with a reward or a punishment. Operant Conditioning a. Skinner Box - levers, reward, electric shocks b. Behavior first, reward second What type of learning? Trial & Error & Observational Learning Observational Learning Social learning: learning by observing others Vervet monkeys learning correct use of alarm calls. Imprinting 1. A strong association learned during a specific developmental period "Sensitive Period" or "Critical Period" 2. learning a releaser for an innate behaviors California condors raised in captivity are reared by Condor puppets Goose imprinting by Conrad Lorenz Geese imprint on the first moving (with sound) object that they see after birth There is a selection of a specific period of time (critical period- within hours of hatching) for social attachment and mate recognition in geese (to ensure geese imprint on the same species) Latent Learning- learning is not evident until later • • • Mice Wander through a Maze unrewarded Mice developed a cognitive map of the maze Learning became evident when mice could run the maze quickly when motivated by food. Insight, reasoning 1. manipulating concepts in the mind to arrive at adaptive behavior 2. mental trial-and-error 3. internal memory stores are used as additional sensory/information source All examples of tool-using: • • • • chickadees/tits and opening milk bottles Egyptian Vulture - uses rocks Cocos Finch - uses splinters of wood North American Gulls, Northwestern Crow - smash clams on sandy beaches Insight Learning Cognition is the ability of an animal’s nervous system to perceive, store, process, and use information gathered by sensory receptors Spatial Learning Cognitive Map: internal representation of spatial relationship among objects in an animal’s surroundings Birds use spatial maps to relocate nut caches Niko Tinbergen Hypothesis: digger wasps use visual Landmarks to keep track of her nests Cognitive Map Visual cue is arrangement pattern rather than objects themselves Communication Pheromones – chemicals emitted by members of one species that affect other members of the species (eg. Queen bee, fruit fly, fish, termites, trees, humans) Visual signals – eg. Warning flash of white of a mockingbird's wing Tactile (touch) – eg. Male fruit fly taps female fly Auditory signals – screech of blue jay or song of warbler Honeybee dance language Used to inform other bees about distance and direction of travel to food sources Eating and Reproduction Foraging: food-obtaining behavior • • Recognize, search for, capturing, and consuming food Optimal Foraging Behavior- Minimize costs / Maximize benefits Energy costs and benefits in foraging behavior Balancing Risk and Reward • Risk of predation affects foraging behavior. - For example, mule deer are more likely to feed in open forested areas where they are less likely to be killed by mountain lions. Sexual selection • • Sexual Dimorphism Ornaments correlate in general with health and vitality Natural selection favors mating behavior that maximizes the quantity or quality of mating partners Courtship behavior consists of patterns that lead to copulation and consists of a series of displays and movements by the male or female. Mating systems differ among species. - • • • Promiscuous: no strong bond pairs between males and females. Monogamous: one male mating with one female. Polygamous: an individual of one sex mating with several of the other sex. o Polygyny where a single male mates with many females. o Polyandry one female mates with several males. In polygamous relationships, an individual of one sex mates with several individuals of the other sex. Species with polygamous mating systems are usually sexually dimorphic: males and females have different external morphologies. Polygamous relationships can be either polygynous or polyandrous. In polygyny - one male mates with many females. The males are usually more showy and larger than the females. Polygynous species – Male larger and more dominant • • • In polyandry = one female mates with many males. The females are often more showy than the males. Polyandry is a rare mating system. Polyandrous species – female has multiple partners • Parental investment refers to the time and resources expended for raising of offspring. - It is generally lower in males - Females usually invest more time into parenting (fecundity, egg size, care of offspring) - Females are usually more discriminating in terms of the males with whom they choose to mate. o Females look for more fit males (i.e., better genes), the ultimate cause of the choice. • Needs of the young are an important factor constraining evolution of mating systems. • Consider bird species where chicks need a continuous supply of food. - A male maximizes his reproductive success by staying with his mate, and caring for his chicks (monogamy). • Consider bird species where chicks are soon able to feed and care for themselves - A male maximizes his reproductive success by seeking additional mates (polygyny). • • • • • Females can be certain that eggs laid or young born contain her genes; however, paternal certainty depends on mating behavior. Certainty of paternity influences parental care and mating behavior. Paternal certainty is relatively low in species with internal fertilization because mating and birth are separated over time. Certainty of paternity is much higher when egg laying and mating occur together, as in external fertilization. In species with external fertilization, parental care is at least as likely to be by males as by females. Paternal care by a male jawfish Applying Game Theory • • • • • In some species, sexual selection has driven the evolution of alternative mating behavior and morphology in males. The fitness of a particular phenotype (behavior or morphology) depends on the phenotypes of other individuals in the population. Game theory evaluates alternative strategies where the outcome depends on each individual’s strategy and the strategy of other individuals. For example, each side-blotched lizard has a blue, orange, or yellow throat, and each color is associated with a specific strategy for obtaining mates. There is a genetic basis to throat color and mating strategy. Like rock-paper-scissors, each strategy will outcompete one strategy, but be outcompeted by the other strategy. The success of each strategy depends on the frequency of all of the strategies; this drive frequency-dependent selection. Male polymorphism in the side-blotched lizard Agonistic behavior • Agonistic behavior is a contest involving threats. - Submissive behavior. - Ritual: the use of symbolic activity. - Generally, no harm is done. Inclusive fitness can account for the evolution of altruistic social behavior • • • • Natural selection favors behavior that maximizes an individual’s survival and reproduction. These behaviors are often selfish. On occasion, some animals behave in ways that reduce their individual fitness but increase the fitness of others. This kind of behavior is called altruism, or selflessness. Altruism Example: Under threat from a predator, an individual Belding’s ground squirrel will make an alarm call to warn others, even though calling increases the chances that the caller is killed. Inclusive Fitness Altruism can be explained by inclusive fitness. Inclusive fitness is the total effect an individual has on proliferating its genes by producing offspring and helping close relatives produce offspring. - Hamilton’s Rule and Kin Selection. o William Hamilton proposed a quantitative measure for predicting when natural selection would favor altruistic acts. o Hamilton’s rule states that natural selection favors altruistic acts. Worker bees Hamilton’s Rule and Kin Selection • Natural selection favors altruism when: rB > C Three key variables in an altruistic act: - Benefit to the recipient (B) Cost to the altruist (C) Coefficient of relatedness (the fraction of genes that, on average, are shared; r) Reciprocal Altruism • • Altruistic behavior toward unrelated individuals can be adaptive if the aided individual returns the favor in the future. This type of altruism is called reciprocal altruism. Reciprocal altruism is limited to species with stable social groups where individuals meet repeatedly, and cheaters (don’t reciprocate) are punished. Reciprocal altruism has been used to explain altruism between unrelated individuals in humans. Social Learning • • • Social learning is learning through the observation of others and forms the roots of culture. Culture is a system of information transfer through observation or teaching that influences behavior of individuals in a population. Culture can alter behavior and influence the fitness of individuals. Case Study: Mate-Choice Copying • • • In mate-choice copying, individuals in a population copy the mate choice of others. This type of behavior has been extensively studied in the guppy Poecilia reticulata. Females who mate with males that are attractive to other females are more likely to have sons that are attractive to other females. Case Study: Social Learning of Alarm Calls • • Vervet monkeys produce distinct alarm calls for different predators. Infant monkeys give undiscriminating calls but learn to fine-tune them by the time they are adults. Sociobiology places social behavior in an evolutionary context Social behavior is any kind of interaction between two or more animals, usually of the same species. Orca and Weddell Seal Orcas chasing Dusky Dolphin Competitive social behaviors often represent contests for resources Sometimes cooperation occurs. Reconciliation behavior often happens between conflicting individuals. • Dominance hierarchies involve a ranking of individuals in a group (a “pecking order”). - Alpha, beta rankings exist. o The alpha organisms control the behavior of others. • Territoriality is behavior where an individual defends a particular area, called the territory. - Territories are typically used for feeding, mating, and rearing young and are fixed in location. Evolution and Human Culture • • No other species comes close to matching the social learning and cultural transmission that occurs among humans. However, our social and cultural institutions may provide the only feature in which there is no continuum between humans and other animals. Learning You should now be able to: 1. Distinguish between the following pairs of terms: kinesis and taxis, classical and operant conditioning. 2. Suggest a proximate and an ultimate cause for imprinting in newly hatched geese or other behaviors. 3. Explain how associative learning may help a predator avoid toxic prey. 4. Describe how cross-fostering experiments help identify the relative importance of environmental and genetic factors in determining specific behaviors. 5. Describe optimal foraging theory. 6. Define and distinguish among promiscuous, monogamous, and polygamous mating systems.