Chapter 27: Animal Behavior What is behavior? The response an organism or group of organism’s have towards their environment is called “behavior.” In the

Chapter 27: Animal Behavior

What is behavior?•The response an organism or group of organism’s have towards their environment is called “behavior.” In the wild there is both group behavior and individual behavior.

•Example of individual behavior: hunting, mating calls, sleeping habits, etc.

•Example of group behavior: migrating, flocking, schools of fish, etc.


Behavior lets organisms respond rapidly and adaptively to their environment. Usually in a beneficial way.Examples?

Plant bends toward light

Pufferfish inflates when threatened

Cat comes when you use a can opener

Toad releases poison when grabbed


Why is behavior important and how does it work?

• Detecting and responding to stimuli is key to an individual’s survival. There are two types of stimuli:

• Internal stimuli tell an animal what is occurring in its own body.– hunger– thirst– pain


• External stimuli give an animal information about its surroundings.– sound– sight– changes in day length or temperature


• Specialized cells that are sensitive to stimuli detect sensory information.– information is transferred to the nervous system– nervous system may activate other systems in response

• Animal behaviors help to maintain homeostasis.


Turn to your neighbor: Review! What are the types of cells found within the nervous system?


• There are two examples of movement-related behaviors:

– Kinesis is an increase in random movement.Example: Pill bugs increase activity as they dry out to find moist

areas

– Taxis is movement in a particular direction either toward or away from a stimuli

–Example: plants growing toward light, deer running away from rustling in the brush


Why do particular behaviors occur? Internal and external stimuli usually interact to trigger specific behaviors.

• Most behaviors are a response to both internal and external stimuli– Combination, not just one stimuli

• External stimuli may trigger internal stimuli.• Green anole reproductive behavior is triggered by internal

and external stimuli.– External: males become aggressive and court females– Internal: females release hormones that make females

receptive


Turn to your neighbor: How could internal and external stimuli cause you to wake up in the morning?


Some behaviors occur in cycles.

• A circadian rhythm is the daily cycle of activity.– occurs over a 24-hour period– run by a biological clock


• Turn to your neighbor: Turn to your neighbor: When people travel, they often complain that the jet-lag is messing with their “Circadian Rhythm.” Explain what they mean.


• Behaviors may occur daily, monthly, seasonally, or annually.– During hibernation, an animal enters a seasonal dormant

state.


• Turn to your neighbor: What kind of stimuli might trigger hibernation?


• Behaviors may occur daily, monthly, seasonally, or annually.

– During migration, animals move seasonally from one portion of their range to another.

– During hibernation, an animal enters a seasonal dormant state.


• Turn to your neighbor: Is migration an individual or group behavior?


Nature vs. NurtureBoth genes and environment affect an animal’s behavior.


What is an “instinct” ?

• An instinct is a complex inborn behavior.

• Instinctive behaviors shareseveral characteristics.– innate, or performed

correctly the first time– relatively inflexible– Why would instincts be

necessary?– Baby Swimming Reflex


Many behaviors have both innate and learned components.

• Learning takes many forms.• Imprinting is an example of learned behavior.• Imprinting: when an organism copies behavior they

observe, usually shortly after their birth• Example: Graylag geese imprint 12 hours after hatching:

they learn to follow around their parents. Scientists who work with these geese have to be careful not to let hatchlings imprint on them instead of their geese parents.


Turn to your neighbor: Why might this person be wearing a goose costume?


• Imitation: When organisms copy behaviors they see displayed by others– young male songbirds

learn songs by listening to adult males

– Children learning to talk– snow monkeys and

potato-washing behavior…younger teaches older


Conditioning

• The behavior of an organism is not constant: it can change depending on the organism’s surroundings. Conditioning describes the way an organism’s behavior changes based on whether the behavior results in a positive or negative outcome. There are two types of conditioning:


– Classical conditioning: previously neutral stimulus associated with behavior triggered by different stimulus

– Ivan Pavlov and salivating dog


– Operant conditioning: behavior increased or decreased by positive or negative reinforcement

– B.F. Skinner and “Skinner boxes”


• Turn to your neighbor: Explain how bells are used to condition student behavior.


All behaviors have benefits and costs

• The benefits of a behavior are increased survivorship (# of individuals that survive from one year to the next) and reproduction rates.– both increase an individual’s fitness; favored by natural

selection– both have costs


• Behavioral costs can be divided into three categories.

– energy costs: energy not available for other tasks– opportunity costs: time spent cannot be used on another

task– risk costs: need food but risk getting eaten

Some behaviors seem harmful but are beneficial


• Turn to your neighbor: If a song-bird spends an entire day trying to attract a mate, what is one opportunity-cost of this behavior?


Animals perform behaviors whose benefits outweigh their costs.

• Behaviors evolve only if they improve fitness.• Territoriality refers to the control of a specific area.


Living in groups also has benefits and costs.

• Social behaviors evolve when the benefits of group living outweigh its costs.– benefits: improved

foraging, reproductive assistance, reduced predation

– costs: increased visibility, competition, disease contraction

• Group living requires learning social structure and membership.


Are humans more intelligent than other animals?

• Insight is the ability to solve a problem mentally without repeated trial and error. – observed in primates, dolphins, and corvids– chimpanzee retrieving hanging bananas


Cognitive ability may provide an adaptive advantage for living in social groups.

• Intelligence in animals seems to be correlated with two characteristics.

1. relatively large brains for their body size

2. live in complex social groups


• Cultural behavior spreads through a population by learning, not by selection.– taught to one generation by another– aided by living in close proximity

Documents

Chapter 27: Animal Behavior What is behavior? The response an organism or group of organism’s have towards their environment is called “behavior.” In the