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Lecture PowerPoint to accompany
Inquiry into Life
Twelfth Edition
Sylvia S. Mader
Chapter 32
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
32.1 Nature versus Nurture:
Genetic Influences
• Behavior
– Any action that can be observed and described
– Genes, to a degree, control behavior
32.1 Nature versus Nurture:
Genetic Influences
• Experiments with Lovebirds, Snakes, and Snails
– 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. They cut
strips and try to tuck them into feathers, but are unsuccessful
• These studies support the hypothesis that behavior has a
genetic basis.
Nest Building Behavior in Lovebirds
32.1 Nature versus Nurture:
Genetic Influences
• Experiments with Lovebirds, Snakes, and Snails
– 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
• This study suggests a genetic basis for feeding
preference
Feeding Behavior in Garter Snakes
32.1 Nature versus Nurture:
Genetic Influences
• Experiments with Lovebirds, Snakes, and Snails
– Garter Snake Experiments
• Determined that sensory receptors are specific for prey
– Researchers presented baby snakes with slug extract on cotton
swabs and then counted the number of tongue flicks
» Coastal snakes had a higher number of tongue flicks than
inland snakes
» Apparently, 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.
32.1 Nature versus Nurture:
Genetic Influences
• Experiments with Lovebirds, Snakes, and Snails
– Snail experiments
• Show role of endocrine system in behavior
• ELH- egg-laying hormone was isolated in Aplysia snails
• ELH 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
32.1 Nature versus Nurture:
Genetic Influences
• Experiments with Humans
– Twin Studies
• Look at characteristics of twins raised apart
• Many share common preferences in food, activity patterns,
and mate selection
32.2 Nature versus Nurture:
Environmental Influences
• Environmental influences also affect behavior
• Fixed Action Patterns (FAP): specific behaviors
elicited by a sign stimulus
• Learning: A durable change in behavior brought
about by experience
32.2 Nature versus Nurture:
Environmental Influences
• Learning in Birds
32.2 Nature versus Nurture:
Environmental Influences
• Learning in Birds
– Imprinting: a simple 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 are sensitive to parents vocalization even before
hatching
32.2 Nature versus Nurture:
Environmental Influences
• Learning in Birds
– 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
32.2 Nature versus Nurture:
Environmental Influences
• Associative Learning
– A change in behavior that involves an association
between two events.
– Classical Conditioning
• The presentation of two different types of stimuli at the same
time causes an animal to form an association between them.
– Operant Conditioning
• A stimulus-response connection is strengthened
Classical Conditioning
32.2 Nature versus Nurture:
Environmental Influences
• Associative Learning
– Operant Conditioning
• Training an animal by rewarding it
32.3 Adaptive Mating Behavior
• Sexual Selection: adaptive changes that
increase ability to attract a mate
• Biological Fitness: ability to produce surviving
offspring
32.3 Adaptive Mating Behavior
• Female Choice
– Female animals produce few eggs, choosing a mate
is a serious consideration.
– Two Hypotheses:
• 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
32.3 Adaptive Mating Behavior
• Female Choice
– The plumage of the
male Raggiana birds
of paradise may signal
health and vigor to the
females.
32.3 Adaptive Mating Behavior
• Male Competition
– Males can produce many offspring because
continuously produce sperm in large numbers
– Less time and energy invested in reproduction
– Males compete to inseminate as many females as
possible
32.3 Adaptive Mating Behavior
• Male Competition
– Cost / Benefits
• Baboons have dominance hierarchies. Dominant males
mate more often than subordinates. Yet the dominant male
is more likely to be in fights, therefore increasing the chance
of injury.
• Males red deer stags compete for a harem of a particular
territory. The harem master is large and powerful with little
body fat. Little body fat increases the chance of starvation if
food is scarce.
A Male Baboon Displaying Full Threat
Competition Between Male Red Deer
32.3 Adaptive Mating Behavior
• Mating in Humans
– Human Males Compete
• Women invest more time and energy in a child biologically
– Nine 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 a price. The average life span is seven years less
than females.
32.3 Adaptive Mating Behavior
• Mating in Humans
– Females Choose
• In one study, the ability to achieve financial success was
found to be the most preferred trait by females
• Other studies have shown that facial body symmetry is
important
– Men Also Have a Choice
• Men prefer youthfulness and attractiveness in females, signs
that their partner can provide them with children.
• By choosing younger women, older men can increase their
fitness.
32.4 Sociobiology and Animal
Behavior
• Sociobiology applies the principles of
evolutionary biology to the study of social
behavior in animals.
• Hypothesis: Living in a society has a greater
reproductive benefit than reproductive cost.
32.4 Sociobiology and Animal
Behavior
• Benefits of Group Living
– Helps an animal avoid predators, rear offspring, and
find food.
• Disadvantages to Group Living
– Competition among members of the group for
resources and exposes group members to illnesses
and parasites.
32.4 Sociobiology and Animal
Behavior
• Sociobiology and Human Culture
– Humans live in organized societies.
– The culture of a human society involves a wide
spectrum of customs.
– The earliest organized societies may have been the
“hunters-gatherers.”
– A predatory lifestyle likely encouraged the evolution of
intelligence and the development of language.
32.4 Sociobiology and Animal
Behavior
• Altruisms versus Self-Interest
– Altruism includes behaviors that sacrifice the
individual for the benefit of the group
– 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
• Helpers at the Nest
– Minimal short-term reproductive sacrifice made to
maximize future reproductive potential
– Helper contributes to survival of kin
Inclusive Fitness
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
Use of a Pheromone
(Chemical Communication)
A Chimpanzee with a Researcher
(Auditory Communication)
Visual Communication
Communication Among Bees
(Tactile Communication)