Chapter 51: Animal Behavior

Featuring Star Teachers:Ryan O’KaneTorpey White

and Zakk Drumm

51.1 Discrete Sensory Inputs Can Stimulate Both Simple and Complex Behaviors

• Ethology – the study of how animals behave in their natural environments

• Four questions in understanding behavior:1) What stimulus elicits the behavior, and what physiological

mechanisms mediate the response?2) How does the animal’s experience during growth and development

influence the response?3) How does the behavior aid survival and reproduction?4) What is the behavior’s evolutionary history?

Proximate and Ultimate Causation

• Proximate causation – how a behavior occurs or is modified (questions 1 and 2 on the last slide)– Ex. How do seasonal changes affect mating?

• Ultimate causation – why a behavior occurs in the context of natural selection (questions 3 and 4)– Ex. Why does reproduction only take place in summer?

• Behavioral ecology – the study of the ecological and evolutionary basis for animal behavior, combination of proximate and ultimate causation

Fixed Action Patterns

• Fixed action pattern – a sequence of unlearned acts that is essentially unchangeable and, once initiated, usually carried to completion– Ex. Male three-spined stickleback fish see red and automatically

attack it (experiment by Niko Tinbergen)• Sign stimulus – an external cue that triggers a fixed action

pattern

Oriented Movement

• Kinesis – a change in activity or turning rate in response to a stimulus– Sow bugs respond to humidity, becoming less active in humid areas

and more active in dry areas• Taxis – an oriented movement toward or away from a stimulus– Toward the stimulus is a positive taxis and away is a negative taxis– Trout orient themselves upstream

• Migration – regular, long-distance change in location– Can track position using sun, circadian clock, North Star, magnetic field

Behavioral Rhythms

• Circadian rhythm normally synchronized with light and dark cycles, role in daily activities

• Circannual rhythms – behavioral rhythms linked to the yearly cycle of seasons, still influenced by light and dark cycles

• Other animals track lunar cycles– Fiddler crabs

Signals

• Signal – a stimulus transmitted from one animal to another• Communication – the transmission and reception of signals• Stimulus-response chain – the response to each stimulus is the

stimulus for the next behavior

Forms of Communication

• Visual communication – sight– Male fruit fly sees female

• Chemical communication – transmission and reception of signal molecules– Female releases chemicals to attract male

• Tactile communication – touch– Male taps female with foreleg

• Auditory communication - sound– Male uses wings to perform courtship song

Bee Communication

• Symbolic language used to share information• Bees perform “dances” to show where and how far food

sources are– Round dance used if food source close to hive, follower bees search

for food– Waggle dance shows distance and direction of food relative to sun– Additional information: Figure 51.8

Pheromones

• Pheromones – chemical substances used for communicating through odor

• Common among mammals and insects for reproduction• Can reach several kilometers away• Not necessarily for reproduction– Catfish release an alarm substance when harmed to warn other fish

51.2 Learning Establishes Specific Links Between Experience and Behavior

• Innate behavior – behavior that is developmentally fixed and under strong genetic control

• Learning – the modification of behavior based on specific experiences

Habituation

• Habituation – a loss of responsiveness to stimuli that convey little or no new information– One of the simplest forms of learning

• Stops wasting energy on stimuli that are irrelevant so animal can focus on signals of food, mates, or danger– Contributes to individual fitness

Imprinting

• Imprinting – the formation of a long-lasting behavioral response to a particular individual or object at a specific stage in life

• Contains innate and learned components• Has a sensitive period– Sensitive period (critical period) – a limited developmental phase when certain

behaviors can be learned• Young imprints on parent and learns basic behaviors• Imprinting stimulus – something to which the imprinting response is

directed– Greylag geese imprint on nearby object that is moving away

Spatial Learning

• Spatial learning – the establishment of a memory that reflects the environment’s spatial structure– Wasps able to use landmarks to find nest

• Cognitive map – a representation in the nervous system of the spatial relationships between objects in an animal’s surroundings– Clark’s nutcracker hides seeds at the halfway point between

landmarks

Associative Learning

• Associative learning – the ability to associate one environmental feature with another– Eating prey with a bad taste dissuades animals from eating similar looking prey

• Two types of associative learning:– Classical conditioning – an arbitrary stimulus becomes associated with a particular

outcome (Pavlov’s dogs)– Operant conditioning – trial and error learning, behaviors associated with a

reward or punishment• Predators learn to avoid prey that have been associated with painful experiences in the past

• Some features can’t be linked– Pigeons can associate color with food, but not with danger

Cognition and Problem Solving

• Cognition – the process of knowing represented by awareness, reasoning, recollection, and judgment– Present in many animals, including insects

• Problem solving – the cognitive activity of devising a method to proceed from one state to another when faced with obstacles– Highly developed in some mammals, especially primates and

dolphins– Many learn to solve problems by observing others

Development of Learned Behaviors

• Some behaviors learned in stages– White-crowned sparrows memorizes the song of its species during

the sensitive period– Juvenile bird compares its own singing with the memorized song until

they match and the song crystallizes

51.3 development of behavior• Experience and behavior• Cross-fostering study- the young of one species is placed with parents of another species.

Used for identifying environmental contributions to the development of behavior. Measured by how much a particular animal’s behavior deviates from the norm of its species.

• This test was performed with mice in California. One species of mice was particularly aggressive, the other was a more passive species. When pups from each species were put with the other species, their behavior changed. In other words, the less aggressive mice became aggressive and vice versa with the other species.

• A common way to test humans for genes responsible for behavior is with twin studies. • Twin study- researchers compare the behavior of twins to see if behavior is identical. The

similarities are used to calculate the likely hood that behavior is controlled by genetics.

Regulatory genes and behavior

• Scientists are searching for genes that control behavior. One gene, fru, has been shown to be responsible for male courtship rituals in fruit flies.

• Fru has been labeled as a regulatory gene that controls a series of genes responsible for the actions of male courtship. It programs the fly for male courtship behavior by overseeing a male-specific wiring of the central nervous system.

• Experiment- Charles Henry crossed two identical species of lacewings that sang different songs. He wanted to see if a single gene controlled the song. The cross resulted in a hybrid that had the chirp of one species but the interval between the chirps of the other species. Because the song has elements of both species, Charles Henry concluded that it was controlled by multiple genes.

Genetic based variation• Genetically based behavioral variation• Variation in migratory patterns• Study performed by Peter Berthold showed that differences in migratory patterns

in the same species of birds were genetic. • Variation in prey selection • Prey choice was shown to be genetic by taking new born snakes and offering them

selection of prey. They only picked pray similar to the prey of their parents and species. • Influence of single locus variation • Many genes control behavior, but a change in one can have drastic effects. One

gene for behavior differs in two closely related species of voles. One causes males to care immensely for their young; in the other the males practically ignore them.

51.4 sexual selection and behavior

• Foraging behavior• Foraging -the act of obtaining food • Evolution of foraging behavior• In a species of fly, two genes can be expressed to control

foraging behavior. It has been shown that population size dictates which one is expressed. One gene makes flies travels large distances to obtain food, this is expressed in smaller populations. In larger populations, the sitter gene is expressed. Fly that express this gene don’t travel far for food.

• Optimal foraging behavior• Optimal foraging model- a model that describes the ideal

situation of foraging for an animal. • Scientists use a cost benefit scale similar to one used in economics. • Balancing risk and reward• Many factors determine the foraging patterns of animals. The

biggest consideration is predation. Foraging patterns often correlate to predation patters. Animals tend to feed where there is a low risk for predation.

• Mating systems and Parental care• Promiscuous matting- matting that forms no lasting bonds, seen in most species. • Monogamous- one male one female• Polygamous- on individual of one sex mating with many of the other. • Polygyny- one male multiple females, most common polygamy• Polyandry- one female, multiple males • Evolutionary advantages to each, varies from species to species.• Monogamy allows one parent to gather resources and the other parent to protect the

young. • Polygamy- allows for greater reproductive success. Common in species where males

protect the females and the young, such as lions.

Monogamy

Polygamy

Polyandry

• Mate choice by females• Selective reproduction by females usually leads to more positive traits being

passed down. Such as feather color, or the size of certain appendages.• Male competition for mates• In many species, males compete for the “right” to mate. • Agonistic behavior- behavior between males that determines who gets

to mate. • Game theory• Game theory- evaluates the consequences of decisions animals didn’t

make when selecting for mates.

51.5: How altruistic behavior fits in with Darwinian evolution

• Most animal behaviors are inherently selfish.• However, many organisms will act altruistic• Altruism: -animals fitness, +population’s• Ex. Naked Mole Rat Colonies• Bees• Warning cries (book uses squirrels as example)

• Inclusive Fitness: the total effect an individual has on proliferating its genes by producing its own offspring AND by providing aid that enables other close relatives (who share similar DNA) to survive and reproduce.

• This idea of inclusive fitness is one of the simplest of reasons that altruism is evolutionarily advantageous.

• Was proposed by biologist William Hamilton.

Kin Selection

• Hamilton’s 3 key variables for altruism: Cost to altruist (C), benefit of recipient (B), and coefficient of relatedness (R).

• Coefficient of relatedness (r): fraction of genes that are shared between siblings on average.

• Natural Selection favors rB>C• Called ‘Hamilton’s Rule’

• Kin Selection: the natural selection that favors altruistic behavior by enhancing reproductive success of relatives

• Weakens with heredity distance; British Geneticist J.B.S. Haldane joked he would lay his life down only for 2 brothers or 8 cousins.

• Explains all the previously stated altruistic behaviors in the examples.

More Altruism

• Sometimes, especially in human behavior, organisms act out to help non related organisms.

• While seems counter-productive, game theory proves it is a winning strategy: called ‘tit-for-tat’

• Not in book- a recent article/study shows that ‘tit-for-tat-with-forgiveness’ is successful in the long run- explains forgiving behavior in humans.

Social Learning

• Social Learning: type of learning that occurs through observing others

• Forms the beginning of culture: as system of information transfer through social learning or teaching that influences the behavior of individuals in a population.

• Mate-choice copying: a behavior in which individuals in a population copy the mate choice of others.

• Ex. Guppies• Social Learning Ex. Vervet monkey’s warning calls

Sociobiology

• Sociobiology: the discipline of study dealing with human culture as it is related to evolutionary theory.

• Human behavior is influenced by genetics and evolution, but not as rigidly as those lower species.

• We are special- says narcissistic socio-biologists everywhere.

Quiz Time! Essays!

• These may include content we did not teach- this is what the AP Test is like. Deal with it.

• 2007 AP Bio Essay Form B Question 1• 1. Without adaptive behaviors, animals would not survive

a. Describe what innate and learned behaviors are. Explain the adaptive value of each of these two categories of behavior to an individual animal.

b. During mating season, male snakes exhibit tracking behavior when they follow chemical pheromone trails deposited on the ground by females. Design a controlled experiment to determine whether a male garter snake will track only a female of his species or will also follow a female of a related species.

• Now, my essay:• Its much easier, lets not make fun of me (Torpey White) for the

bad question. • A. Explain and describe how animal behavior is linked to

evolutionary biology. Give at least 3 examples. • B. Define Altruism. How is altruism allowable given natural

selection and evolutionary forces, and explain how game theory has lead to discoveries in this field.