UNIT 10

Animal Behavior

Introduction

Humans have always studied animal behavior Knowledge of animal behavior = human survival

For example, understanding behavior of animals hunted for food

Behavioral ecology – Studies how animal behavior is controlled and how it develops, evolves, and contributes to survival and reproductive success For example, does play serve a developmental function? How does migration contribute to reproductive success

An organism’s behavior is tied to survival & successful reproduction

Introduction (Page 2)

Ethology – Study of behavior & its relationship to its evolutionary origins The study of how animals behave, especially in their

native habitat

3 Important Ethologists: Karl von Frisch – Honeybee communication & waggle

dance Niko Tinbergen – Fixed action pattern Konrad Lorenz - imprinting

2 Levels of Behavioral Studies

Proximate causes of behavior “How” questions Include the effects of heredity on behavior, genetic-

environmental interactions

Ultimate causes of behavior “Why” questions Studies of the origin of behavior Utility of behavior in terms of reproductive success

Behavior, what is it?

Is it part of an organism’s phenotype or genotype?

Are hormonal secretions considered behavior?

Behavior is…

Fixed Action Pattern (FAP)

Commonly called innate behaviorHighly stereotypic behaviorTriggered by a sign stimuli (external stimulus)When stimuli are exchanged between members of

the same species, the stimuli are called releasers Once begun, the behavior will continue to

completion

Example: Stickleback fish Sign stimulus: red underbelly (only males have red underbelly)

in another male’s territory Behavior triggered: Male attacks red-bellied stickleback fish or

model

Stickleback Fish

Which models will produce an aggressive response?

Learning

Def – sophisticated process in which the responses of the organism are modified as a result of experience

Def 2 – modification of behavior based on specific experience

Capacity to learn can be tied to Length of life span

Animals with a short life span (eg Drosophila) have no time to learn, so these species rely on FAP behaviors

Complexity of the brain Dolphins – more convolutions in the brain than any other

species, so an increased reliance on learned behavior

Habituation

One of the simplest forms of learningDef – loss of responsiveness to stimuli that

convey little or no influenceExample: Cry-Wolf effect

Although animal may recognize an alarm call for predators But there will be no continued response if the alarm call is

not followed by an actual attack

Example 2: If hydra is in a container, and the side is tapped = recoiling If no harm is encountered after repeated tappings, the

hydra will ignore the tapping – it has habituated to the stimulus

Associative Learning

Def – Type of learning where a stimulus is associated with another through experience

2 Types of Associative Learning1. Classical Conditioning – Ivan Pavlov

-- Pavlov rang bell whenever dog was fed-- Soon even if no food was present, dog salivated when

bell was rung-- Dog was conditioned to associate bell sound with food

2. Operant Conditioning – (trial and error learning)-- An animal learn to associate one of its behaviors with a reward or punishment-- Animal then repeats (rewarded) or avoids (punishment) the behavior

Operant Conditioning

B.F. Skinner (1930’s)NOT Principal Skinner from “The Simpsons”

Rat placed in a cage that contained a lever than when depressed = food pellet

At first, rat depressed by accident = food by accident

Soon, rat associated lever depressing with food appearance

Examples of Operant Conditioning

Imprinting

Def – Learning that occurs during a sensitive or critical period in the early life of an individual

Irreversible

Example: Konrad Lorenz & Geese hatchlings Example of Imprinting: geese hatchlings closely follow their

mother Mother-offspring bonding in animals is crucial to safety &

development of the offspring Geese hatchlings follow the first thing they see that moves Lorenz ensured that he was the first moving organism seen by the

hatchlings Hence, the geese hatchlings had imprinted on Lorenz

Wherever he went, the hatchlings followed

Imprinting (Page 2)

Questions

1. The Stickleback fish is an example of …

2. What are the 2 types of associative learning?

3. Which type of behavior is unlearned?

4. What type of learning allows an organism to ignore a particular stimulus?

5. Lorenz attempted to mimic what learning type?

Examples

Give an example, NOT from the notes, of:

1. Imprinting2. Operant Conditioning (trial and error)3. Habituation4. Classical Conditioning5. Fixed Action Pattern (FAP)

Social Behavior

Def - Any kind of interaction among two of more animals, usually of the same species

Relatively new field of study

5 Social Behaviors to focus on:1. Cooperation2. Agonistic3. Dominance Hierarchy4. Territoriality5. Altruism

Cooperation

Enables individuals to carry out a behavior performed more successfully by a group than individuals Hunting in a pack – enables a number of individuals to

take down a larger prey than any individual would be capable of

Example:

Agonistic Behavior

Aggressive behaviorThreats or actual combat to settle disputes among

individualsAccess to mating, food, or shelterUsually involves ritualistic or symbolic behavior,

instead of actual combat Dogs will bear teeth to try to scare the opponent Loser will display submissive behavior (putting tail between

their legs and running away

Once a dispute has been settled by agonistic behavior, future encounters will not (usually) involve further agonistic behavior

Examples of Agonistic Behavior

Dominance Hierarchy

Pecking Order behaviorDictates social position an animal has in a

cultureAlpha male & female in a populationBeta is next in line in social position

Alpha is assured of first choice of any resource Food after a kill Best territory Most fit mate

Territoriality

Territory – area an organism defends & from which other members of the community are excluded

Territories are established & defended through agonistic behaviors

Territory is important for capturing food, mating opportunities, and rearing young

Size of territory is highly variable due to resources available, and function of the territory

Mating Systems

1. Promiscuous No strong pair bonds

2. Monogamous 1-male & 1-female

3. Polygamous 1 individual mates with several others

Inclusive Fitness

Def – total effect an individual has on proliferating its genes BY

1. Producing its own offspring2. Providing aid to other close relatives to produce

offspring

This behavior is favored by natural selection since it enhances the the reproductive success of relatives

Called Kin Selection

Altruism

Does altruism exist?

Altuism = selflessness Behavior that reduces an individual’s reproductive

fitness, but increases the fitness of the group or familyFor example: when a honeybee stings an intruder,

while it may die, the colony is benefitted Kin selection – Potential explanation for

seemingly altruistic behavior While the individual is sacrificed, the kin are selected as a

result of performance of the behavior So while the entire genome is not passed on, enough is passed

on for the behavior (altruism) to be considered an evolutionary mechanism

Altruism

So does altruistic behavior exist?

Isn’t the honeybee’s offspring benefiting?So the honeybee is not being selfless, but the behavior

eventually results in selection for the organism’s offspring or kin

A more controversial case: A father in India decides that he will donate a kidney for $15,000.

-- Is this altruistic behavior?