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The Living World Fourth Edition GEORGE B. JOHNSON 33 Behavior and the Environment PowerPoint® Lectures prepared by Johnny El-Rady Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.1 Approaches to the Study of Behavior Behavior can be defined as the way an organism responds to stimuli in its environment The most complex behaviors are exhibited by animals with nervous systems Proximate causation – How does it work? Focus of the field of psychology Ultimate causation – Why did it evolve? Focus of the field of ethology (evolutionary behavior) Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.1 Approaches to the Study of Behavior The study of behavior has had a long history of controversy Is behavior the result of nature (instinct) or nurture (learning)? This is no longer considered an “either-or” proposition We now know that instinct and learning play significant roles Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.2 Instinctive Behavioral Patterns Early research in animal behavior focused on patterns that appeared to be instinctive or innate These are the same in all individuals of a species Appear to be based on preset paths in the nervous system Ethology is the study of animal behavior in natural conditions Its founders were Karl von Frisch, Konrad Lorenz, and Niko Tinbergen Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Examples of Innate Behavior Egg retrieval by geese Behavior is triggered by a sign stimulus Egg out of nest Innate releasing mechanism provides the neural instructions that detect stimulus Fig. 33.2a A fixed action pattern is triggered Intricate egg retrieval behavior Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Sign stimuli are often not very specific Male stickleback fish develop red coloration on their undersides during breeding season React aggressively to approach of other males Red color is the sign stimulus Fish displayed aggressive postures when challenged with unfishlike models with red strips! Fig. 33.2b Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.3 Gene Effects on Behavior Behavioral genetics is the study of how genes influence behavior Many behaviors are inherited in Mendelian fashion Crosses of two species showing different behaviors yields hybrids with “intermediate” behavior A study of human twins revealed the following Identical twins separated at birth and raised apart developed many similarities in personality Fraternal twins raised together had personalities no more similar than those raised apart Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.3 Gene Effects on Behavior Normal mother In 1996, the fosB gene was discovered in mice It seems to determine whether female mice will nurture their young Fig. 33.3 Mother with two mutant fosB alleles Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.4 How Animals Learn Learning is the modification of animal behavior as a result of previous experiences Non-associative learning No requirement for an association between two stimuli or between a stimulus and a response Sensitization Repeating a stimulus produces greater response Habituation Decrease in response to a repeated stimulus Learning not to respond to a particular stimulus Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Associative learning Involves formation of an association between two stimuli or between a stimulus and a response The behavior is conditioned Classical conditioning Paired presentation of two stimuli causes an animal to create an association between them Pavlovian conditioning Operant conditioning An animal learns to associate its behavioral response with a reward or punishment Trial-and-error learning Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Imprinting Social attachments to other individuals that will profoundly influence behavior later in life Filial imprinting occurs between parents and offspring Birds will follow the first object they see after hatching They direct their social behavior toward that object as their mother Konrad Lorenz Fig. 33.4 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.5 Instinct and Learning Interact to Determine Behavior Some animals have innate predisposition toward forming certain associations Pigeons learn to associate food with colors but not sounds However, they associate danger with sounds not colors This learning preparedness demonstrates that learning is possible only within the boundaries set by instinct (genes) Knowledge of an animal’s ecology is key to understanding what an animal is capable of learning Clark’s nutcracker have an extraordinary spatial memory These birds have a large hippocampus Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Courtship songs sung by mature birds are species-specific White-crowned sparrows that heard no song at all during rearing, had a poorly developed song as adults The same was true if they heard only the song of a different species, the song sparrow However, birds that heard the song of their own species, sang a fully-developed “whitecrowned” song as adults Fig. 33.5 Thus, song development involves both instinct and learning Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.6 Animal Cognition A central question in animal behavior is whether nonhuman animals show cognitive behavior Do they process information and respond in a manner that suggests thinking? Some examples provide evidence of conscious planning Japanese macaques can separate grain from sand Chimpanzees use twigs to probe entrance to termite nest Sea otters bash clams against rocks to break them open Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display There is also compelling evidence that animals can solve problems Chimpanzees could not get to bananas by jumping They ultimately got to it by placing boxes on top of each other and climbing on them! Ravens figured out how to get to meat at the end of a string They pulled up a bit of string and stepped on it This process was repeated until the food was within reach! Fig. 33.6 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.7 Behavioral Ecology The study of animal behavior can be divided into 1) A study of its development 2) A study of its physiological basis 3) A study of its function Behavioral ecology is the study of how natural selection affects behavior Focuses on the adaptive significance of behavior How behavior may increase survival and reproductive success, or fitness Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.7 Behavioral Ecology Adaptive traits confer evolutionary advantages in different ways Some behaviors reduce predation Egg-shell removal by gulls reduce predation by crows Other behaviors enhance energy intake This allows more offspring to be supported Other behaviors increase resistance to disease Still others enhance the ability to acquire a mate Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.8 A Cost-Benefit Analysis of Behavior Every behavior that offers a survival advantage for an individual comes with an associated cost Foraging behavior allows an animal to choose what food to select, and how far to go seeking it Optimal foraging theory Animals select foods that maximize their net energy intake per unit of foraging time However, avoiding predators is an important consideration Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Territoriality is behavior in which individual members of a species maintain exclusive use of an area Territories are defended by displays and overt aggression Sunbirds increase nectar availability by defending flowers However, a defensive cost is increased predation Fig. 33.8 Thus, for a behavior to be favored by natural selection, the benefits have to outweigh the costs Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.9 Migratory Behavior Many animals breed in one part of the world, and spend the rest of the year in another Long-range two-way annual movements like this are called migrations Migratory behavior is particularly common among birds Ducks and geese Warblers Starlings Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.9 Migratory Behavior Compass sense – An innate ability to move in a particular direction (called follow a bearing) Map sense – A learned ability to adjust a bearing depending on the animal’s location Experiments on starlings indicate that inexperienced birds migrate with an innate compass sense On the other hand, older experienced birds use a learned map sense to aid their navigation Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 33.9 Starlings learn how to navigate Transport of captured birds Flight of experienced birds Flight of inexperienced birds Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.9 Migratory Behavior How is the compass sense achieved? Migrating birds detect the earth’s magnetic field and orient themselves with respect to it Sun and stars may also be used for orientation How is the map sense achieved? Recognition of certain cues, like the position of mountains and coastlines Migration through featureless terrain presents more of a puzzle Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.10 Reproductive Behaviors Reproductive behaviors encompass a variety of animal behaviors, including courtship Competition for mating opportunities has been termed sexual selection Intrasexual selection Competition between members of one sex (usually males) Intersexual selection Essentially, mate choice Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Intrasexual selection leads to evolution of structures used in combat with other males Deer’s antlers or ram’s horns Intersexual selection leads to evolution of complex courtship behaviors and “ornamental” structures Female peahens prefer to mate with males with greater number of eyespots in their tail feathers Fig. 33.10 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display The benefits of mate choice for the female 1. The male that provides the best offspring care 2. The male that provides the best territory 3. The male that provides the best genes The typical number of mates an animal has during its breeding season is called the mating system Monogamy – One male and one female Polygyny – One male and many females Polyandry – One female and many males Polygyny is more common than polyandry Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display An animal’s reproductive strategy involves “decisions” regarding the following The choice of mates The number of mates The time and energy to devote to rearing offspring (parenting) The two sexes of a species often have different reproductive strategies In most animal species, females exercise more mate choice and parental investment Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.11 Communication Within Social Groups Many insects, fish, birds and mammals live in social groups Communicated information includes Alarm calls indicate predators Alarm pheromones trigger attack behavior Trail pheromones organize cooperative foraging Fire ants Fig. 33.11 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display European honeybees use a very complex dance language to direct hivemates to rich nectar sources A scout returning from a foraging trip performs a waggle dance that resembles a figure eight The direction of the food source relative to the direction of the sun is indicated by the angle of the straight run The distance to the food source is indicated by the tempo, or degree of vigor, of the dance Fig. 33.12 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Primate language Some primates have a “vocabulary” that allows individuals to communicate the predator identity The vocalizations of African vervet monkeys distinguish between leopards and eagles Each distinctive call elicits a different and adaptive escape behavior Fig. 33.13 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display All of the roughly 3,000 human languages draw from the same set of 40 consonant sounds Language develops at an early age in humans Individuals who have not heard certain consonant sounds as infants can only rarely produce them as adults Language acquisition goes through several stages “Babbling” Vocabulary of thousands of words Simple sentences that convey information Learning the rules of grammar Nonverbal communication includes “body language” Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.12 Altruism and Group Living Altruism is the performance of an action that benefits another individual at a cost to the actor Helpers at the nest in some bird species Sentinels that give predator-alarm calls in some mammalian species Fig. 33.14 Meerkat The existence of altruism among animals is rather perplexing Natural selection should operate against it Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Altruistic behavior may not be truly altruistic after all The actor may benefit Nest helpers may get parenting experience or inherit territory Sentinels may be able to escape predators in the confusion following the alarm call Individuals may benefit directly if there is a mutual exchange of altruistic acts In reciprocal altruism, “cheaters” (nonreciprocators) are discriminated against These individuals are cut off from receiving future aid Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display An altruist compensates for the reduction in its own reproductive success by increasing that of relatives Selection that favors altruism directed toward relatives is called kin selection The more closely related two individuals are, the greater the potential genetic payoff White-fronted beeeaters Helpers tend to be close relatives Helpers’ assistance increases with genetic relatedness Fig. 33.15 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.13 Vertebrate Societies Vertebrate social groups are usually less rigidly organized and cohesive than insect societies Some vertebrate complex social systems exhibit both reciprocal and kin-selected altruism However, vertebrate societies tend to display more conflict among members than insect societies Conflict (and aggression) center on access to food and mates Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display The organization of vertebrate societies is influenced by ecological factors such as food and predation African weaver birds Savanna-dwelling species build colonial nests Have a polygynous mating system Forest-dwelling species build solitary nests Monogamous pairs form and cooperate to find limited food resources Fig. 33.16 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Naked mole rats are rare among vertebrates in that they form large organized societies These underground colonies have a true division of labor A single female or “queen” does all the breeding Fig. 33.17 Workers, consisting of both sexes, keep the tunnels clear and forage for food Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 33.14 Human Social Behavior Sociobiology is the study of the evolution of social behavior in animals Pioneered by Edward O. Wilson, this field has proven highly controversial No animal exhibits cultural differences to the degree seen in human populations Both genetics and learning play key roles in complex human social behavior However, the extent of each is hotly-debated Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display