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Inquiry into LifeEleventh Edition

Sylvia S. Mader

Chapter 32Lecture Outline

Prepared by: Wendy VermillionColumbus State Community College

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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32.1 Nature versus nurture: genetic influences

• Experiments with lovebirds, snakes, and snails– Behavior-any action that can be observed and described

• Often dependent upon anatomy and physiology- genetically determined

• Genes also play a role

– Lovebird nesting behavior• Fischer lovebirds, Agapornis fischeri, cut strips from leaves and

carry them to their nest site

• Peach-face lovebirds, Agapornis roseicollis, also cut strips but tuck them into their rump feather and carry them that way

• Hybrid lovebirds exhibit intermediate behavior- cut strips and try to tuck them into feathers, but are unsuccessful

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Nest-building behavior in lovebirds

• Fig. 32.1

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Nature versus nurture: genetic influences cont’d.

• Garter snake experiments– Genetic role in food preference

• Inland populations of garter snakes are aquatic and feed in the water on fish and frogs

• Coastal populations are terrestrial and feed on slugs

• In the laboratory, inland snakes refused slugs, while coastal snakes readily accepted them

– Hybrid snakes exhibited intermediate acceptance of slugs as food

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Feeding behavior in garter snakes

• Fig. 32.2

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Nature versus nurture: genetic influences cont’d.

• Further garter snake studies – Determined that sensory receptors are specific for prey

• Presented baby snakes with slug extract on Q-tips and counted number of tongue flicks

– Coastal snakes have many receptors on their tongues for taste and smell of slugs

– Inland snakes do not

• A genetic difference between the two populations results in a physiological difference in nervous systems

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Nature versus nurture: genetic influences cont’d.

• Snail experiments– Show role of endocrine system in behavior– ELH- egg-laying hormone isolated in Aplysia snails controls all

aspects of egg laying behavior• After mating, snail pulls egg string with mouth, winds it in a loose

ball, and attaches it to an object

• When given ELH, snail exhibits all behaviors even without mating

• Human experiments– Twin studies-look at characteristics of twins raised apart

• Many share common preferences in food, activity patterns, and mate selection

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32.2 Nature versus nurture: environmental influences

• Environment also influences behavior• Fixed action patterns (FAP)-specific behaviors elicited by

a sign stimulus– Learning can improve the behavior

• Defined as a durable change in behavior brought about by experience

• Learning in birds– Begging behavior in laughing gull chicks

• Sign stimulus-beak swinging by parent; elicits begging behavior

– Pecking accuracy by chick improves over time-learning component

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Pecking behavior in laughing gulls

• Fig. 32.3

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Nature versus nurture: environmental influences cont’d.

• Learning in birds cont’d.– Imprinting- a form of learning

• Young birds follow the first moving object they see– Sensitive period- time during which imprinting may occur

• Social interactions between parent and offspring during the sensitive period are important

– Young birds sensitive to parent vocalization even before hatching

– Song learning• White-crowned sparrows-species-specific song with different

dialects; experiments show learning plays a role• Birds that heard no songs- sang an undeveloped song as adults• Birds that heard species song-sang in that dialect as long as tape

was played during a sensitive period• Birds that had adult tutor-sang the tutor’s song even if a different

species and no matter when tutoring began

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Nature versus nurture: environmental influences cont’d.

• Associative learning– A change in behavior from an association between 2 events– Classical conditioning-Pavlov’s dogs

• Associate ringing bell with food

• Can train animal to associate any response with any stimulus

– Operant conditioning• Stimulus-response connection is strengthened

• Skinner’s experiments with rats-give a food reward to reinforce a behavior

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Classical conditioning

• Fig. 32.4

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Nature versus nurture: environmental influences cont’d.

• Human culture– Defines proper modes of behavior– Learning of cultural norms is necessary– Cultural traits undergo evolution

• Have both genetic and environmental components

• Traits that had the greatest survival benefits became norms

– Division of labor among humans-possible evolutionary pattern• Human infant is born helpless and requires much care

– Women bear babies, so they always know the baby is their own

» Therefore invest more time in care historically than men

– Women therefore need a long-lasting relationship with men to provide resources

– Led to a division of labor

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32.3 Adaptive mating behavior

• Sexual selection-adaptive changes that increase ability to attract a mate

• Biological fitness-ability to produce surviving offspring• Female choice-few eggs produced so quality is important

– Good genes hypothesis-females choose mates on basis of traits that improve survival

– Run-away hypothesis-females choose mates in bases of traits that improve appearance

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Raggiana Bird of Paradise

• Fig. 32.6

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A male olive baboon displaying full threat

• Fig. 32.7

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Adaptive mating behavior cont’d.

• Male competition– Can produce more offspring because continuously produce

sperm in large numbers– Less time and energy invested in reproduction– Quantity more important than quality because at least some will

survive– Males compete to inseminate as many females as possible; cost

must be less than the benefit• Dominance hierarchies

• Territoriality

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Competition between male red deer

• Fig. 32.8

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Adaptive mating behavior cont’d.

• Mating in humans– Human males compete

• Women invest more time and energy in a child biologically

– 9 month pregnancy and then lactation

• Men only need to contribute sperm during sex act

• Result- men are more available for reproduction than women

– Because more men are available, they must compete

• Humans are dimorphic-men are larger and stronger likely as result of past selection by females

– Males pay price-average life span is 7 years less than females

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Adaptive mating behavior cont’d.

• Females choose– Male mating success correlated best with income in recent study

• Male who can provide resources can help ensure offspring survival

• Males choose– Males generally choose females who can produce the most

offspring

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32.4 Sociobiology and animal behavior

• Sociobiology– Benefits of living in a group

• Predator avoidance

• Finding food

• Rearing of offspring

– Disadvantages • Disputes, aggression increase

– Dominance hierarchies help

• Decreased access to resources for subordinates

• Increased exposure to diseases, parasites

– Social groups will only exist if benefits outweigh disadvantages

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Sociobiology and animal behavior cont’d.

• Altruism versus self-interest– Altruism includes behaviors that sacrifice the individual for the

benefit of the group– Direct selection-adaptation to environment as a result of

reproductive success of an individual– Indirect selection-adaptation as a result of reproductive success

on an individual’s relatives– Inclusive fitness of an individual includes personal reproductive

success as well as that of relatives• Measured by how many genes individual contributes to next

generation

– Behaviors once thought to be altruistic are now recognized to be indirect selection

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Sociobiology and animal behavior cont’d.

• Examples of indirect selection– Older offspring staying behind to help rear new litters– Worker bees, wasps, and ants aiding reproduction by the queen

• Helpers at the nest– Minimal short-term reproductive sacrifice made to maximize

future reproductive potential– Helper contributes to survival of kin

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Inclusive fitness

• Fig. 32.10

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32.5 Animal communication

• Communication- an action by a sender that influences the behavior of the receiver– Chemical communication-pheromones

• Powerful chemical signals passed in low concentration

• May be released into the air or used in territory marking

– Auditory communication• Very rapid and can be modified for specific situations

– Visual communication• Most used by diurnal species-must be able to be seen

• Plumage, courtship “dances”, aggressive displays, etc.

– Tactile communication• Occurs when one individual touches another

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Use of a pheromone

• Fig. 32.11

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A chimpanzee with a researcher

• Fig. 32.12

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Communication among bees

• Fig. 32.13