Behavioral Biology

							CLASSIC CONCEPTS IN BEHAVIOR 37.1 Behavioral biologists study the actions of animals in their natural environments
• Behavioral biology is the study of what animals do when interacting with their environment

• Behavior can be interpreted in terms of proximate causes (immediate interaction with the environment) or ultimate causes (evolutionary differences)

• Early insights into the nature of behavior came from studies by Nobel laureates Karl von Frisch, Konrad Lorenz, and Niko Tinbergen
• They were among the first experimentalists in behavioral biology

• Tinbergen and Lorenz performed experimental studies of innate behavior and simple forms of learning

• A classic Tinbergen experiment deals with the nesting behavior of the digger wasp
– The female wasp often excavates and cares for four or five separate nests

• Tinbergen used this experiment to test his prediction that digger wasps use landmarks to keep track of the location of their nests

• In the experiment, Tinbergen placed a circle of pinecones around a nest opening

Nest

1

Figure 37.1, Part 1

• After the female flew away, Tinbergen moved the pinecones a few feet to one side of the nest opening
– When the female wasp returned, she flew to the middle of the circle of pinecones rather than to the actual nest opening

Nest

No Nest

2

Figure 37.1, Part 2

• Tinbergen next arranged the pinecones in a triangle around the nest and made a circle of small stones off to one side of the nest opening
– This time the wasp flew to the stones

Nest

No Nest

3

Figure 37.1, Part 3

• The wasp cued in on the arrangement of the landmarks rather than the landmarks themselves

• This experiment demonstrated that the wasp did use landmarks and that she could learn new ones to keep track of her nest

• Behavioral ecologists are especially interested in the ultimate causes of behavior, which are evolutionary  Natural selection preserves behaviors that enhance fitness

37.2 Behavior results from both genes and environmental factors • Animal behavior often involves a combination of genetic programming (innate behavior) and environmental experiences (learning)
both genes and the environment influence the development of behavioral phenotypes- just like any other traits

• The gathering of nest materials by lovebirds has genetic and environmental components

Single long strip carried in beak (Fischer’s lovebird)

Several short strips tucked under feathers (peach-faced lovebird)

Tucking failure

Strip in beak Hybrid behavior Figure 37.2

37.3 Innate behavior often appears as fixed action patterns • Sign stimuli (often a simple cue in an animal’s environment) trigger innate, essentially unchangeable fixed action patterns (FAPs) • The genetic programming underlying FAPs ensures that such activities are performed correctly without practice

• The graylag goose always retrieves an egg that has been bumped out of her nest in the same manner
– This is a fixed action pattern – She carries this sequence to completion, even if the egg slips away during the process
Figure 37.3A

• Several key events in the life cycle of the European cuckoo are determined by fixed action patterns
– Egg-laying behavior

1

2

3
Figure 37.3B

– The behavior of the cuckoo hatchling ejecting the host eggs from the nest

– The feeding behavior of a foster mother to the cuckoo chick

Figure 37.3B

37.4 Learning ranges from simple behavioral changes to complex problem solving • Learning is a change in behavior resulting from experience • Habituation is one of the simplest forms of learning
– An animal learns not to respond to a repeated stimulus that conveys little or no information
– For example, birds eventually become habituated to scarecrows and no longer avoid nearby fruit trees

Table 37.4

37.5 Imprinting is learning that involves both innate behavior and experience
• Imprinting is irreversible learning limited to a sensitive period in an animal's life; it enhances fitness by enabling rapid learning
• Example: Lorenz used the graylag goose to demonstrate imprinting. He took over the maternal role for a group of goslings

• Not all examples of imprinting involve parentoffspring bonding
– Although newly hatched salmon do not receive any parental care, they imprint on the complex mixture of odors unique to the freshwater stream where they hatch – This allows salmon to find their way back to the stream to spawn after spending a year or more at sea

• Imprinting plays an important role in song development for many kinds of birds

Figure 37.5B

37.6 Many animals learn by association and imitation • Associative learning is learning that a particular stimulus or response is linked to a reward or punishment
– These ducks have learned to associate humans with food handouts – They congregate rapidly whenever a person approaches the shoreline

Figure 37.6A

• Trial-and-error learning is a common form of associative learning
– An animal learns to associate one of its own behavioral acts with a positive or negative effect

Figure 37.6B

• Imitation is learning by observing and mimicking the behavior of others
– This form of learning is not limited to a sensitive period – Many predators, including cats and coyotes, seem to learn some of their basic hunting tactics by observing and imitating their mother

37.7 Animal cognition includes problem-solving behavior • Some animals exhibit problemsolving behavior
– Examples: chimpanzees and ravens

Figure 37.7A, B

ECOLOGICAL ROLES OF BEHAVIOR 37.8 An animal's behavior reflects its evolution • Behavior is an evolutionary adaptation that enhances survival and reproductive success
• Behavior evolves as natural selection finetunes an animal to its environment
– The hunting and reproduction behaviors of jaguars – Nest location by digger wasps – Imprinting of goslings

37.9 Biological rhythms synchronize behavior with the environment • Animals exhibit a great variety of rhythmic behavior patterns • Circadian rhythms are patterns that are repeated daily
– Sleep/wake cycles in animals and plants

• Circadian rhythms appear to be timed by an internal biological clock

• In the absence of environmental cues, these rhythms continue
– But they become out of phase with the environment
12:12 (natural) Constant darkness

Figure 37.9A

37.10 Animal movement may be oriented to stimuli or landmarks • Movement in a directed way enables animals to
– avoid predators
– migrate to a more favorable environment

– obtain food – find mates and nest sites

TYPES of ANIMAL MOVEMENT
1. kinesis- simplest type of animal movement random movement in response to a stimulus

2. taxis- another simple type
– A more or less automatic movement directed toward or away from some stimulus

–

Examples include rheotaxis (current) chemotaxis, and phototaxis

3. Some animals use landmarks to find their way within an area

37.11 Movement from place to place often depends on internal maps
• Many animals formulate cognitive maps
– Internal representations of spatial relationships among objects in their surroundings (wasp example)

• Some animals undertake long-range migrations
– Examples: whales, sea turtles, birds, monarch butterflies

• Animals navigate using the sun, stars, temperature gradients, landmarks, or Earth's magnetism

• Migrating gray whales use coastal landmarks to stay on course
FEEDING GROUNDS Siberia Alaska Arctic Ocean

NORTH AMERICA Pacific Ocean

Atlantic Ocean

Baja California
BREEDING GROUNDS Figure 37.11A

• The indigo bunting learns a star map and navigates by fixing on the North Star

Paper Ink pad Funnelshaped cage

Figure 37.11B

37.12 Behavioral ecologists use cost/benefit analysis in studying feeding behavior • Animals are generally selective and efficient in their food choices
– Some animals, such as gulls, are feeding “generalists” – Other animals, such as koalas, are feeding “specialists”
Figure 37.12A, B

• The mechanism that enables an animal to find particular foods efficiently is called a search image

• Natural selection seems to have shaped feeding behavior to maximize energy gain and minimize the expenditure of time and energy
– This is the theory of optimal foraging

• Whenever an animal has food choices, there are a number of tradeoffs
– A bass can get more usable energy from minnows, but crayfish are easier to catch – However, it may take more time to eat a crayfish because of its tough exoskeleton

Figure 37.12C

• The kangaroo rat selects high-energy foods (seeds) in a manner that reduces time spent above the ground, where it is exposed to predators

Figure 37.12E

SOCIAL BEHAVIOR AND SOCIOBIOLOGY 37.13 Sociobiology places social behavior in an evolutionary context
• Social behavior is defined as the interaction among members of a population

• The discipline of sociobiology studies social behavior in the context of evolution

37.14 Rituals involving agonistic behavior often resolve confrontations between competitors • Agonistic behavior is social behavior consisting of threats and combat that settles disputes between individuals in a population • Agonistic behavior can directly affect an individual's evolutionary fitness
– The victor often gains first or exclusive access to mates

Figure 37.14

37.15 Dominance hierarchies are maintained by agonistic behavior • Many animals live in social groups maintained by agonistic behaviors • Dominance hierarchy is the ranking of individuals based on social interactions

• Chickens establish a “peck order”

• Resources are often partitioned based upon the dominance hierarchy

Figure 37.15

37.17 Territorial behavior parcels space and resources • Humans tend to space themselves out when they are close to others
– They establish what we might call personal territories

Figure 37.17A

• Many animals exhibit territorial behavior
– It is a form of social behavior that partitions resources

• A territory is an area that individuals defend and from which other members of the same species are usually excluded
– The size of the territory varies with species, the function, and the available resources – Territories are typically used for feeding, mating, and/or rearing young

• Territoriality is often maintained by agonistic behavior
– These New Zealand gannets maintain their individual nesting territories by calling and pecking at each other

Figure 37.17B

• Territoriality can enhance fitness if the benefits of possessing a territory outweigh the energy costs of defending one

• Territorial rights are proclaimed continually in a variety of ways
– Bird songs – Noises, such as the bellowing of sea lions and the chattering of squirrels

– Defecation in open areas – Scent markers, such as urine
Figure 37.17C