Reading Essentials for Biology Glencoe (794133), страница 90
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How do animalsknow when to migrate? Write your thoughts on the lines below.______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.What is behavior?A peacock displaying his colorful tail, a whale spending the winter months in the ocean off the coast of southern California, and alizard seeking shade from the hot desert sun are all examples ofanimal behavior.
Behavior is anything an animal does in responseto a stimulus. A stimulus is an environmental change that directlyinfluences the activity of an organism. The presence of a peahenstimulates the peacock to open its tail feathers. A change in thelength of daylight hours may cause the whale to leave its summertime arctic habitat. Heat stimulates the lizard to seek shade.Identify MainIdeas This section introducesinnate behavior.
Skim thesection and highlight threeimportant facts about innatebehavior.Inherited BehaviorInheritance plays an important role in the ways animals behave.You would not expect to see a hummingbird tunnel undergroundor a mouse fly. Yet, why does a mouse run away when a catappears? Why does a hummingbird fly south for the winter?These behaviors are genetically programmed. An animal’s geneticmakeup determines how that animal reacts to certain stimuli.Does natural selection favor certain behaviors?Often, a behavior exhibited by an animal species is the result ofnatural selection.
A variety of behaviors among individuals affectstheir ability to survive and reproduce. Individuals with behaviorthat makes them more successful at surviving and reproducingusually produce more offspring. These offspring inherit the geneticbasis for the successful behavior. Individuals with less successfulbehavior produce fewer offspring or none at all.READING ESSENTIALS1. How does naturalselection favor certainbehaviors?________________________________________________________________________Chapter 33397NameDateClassSection33.1Innate Behavior, continuedInherited behavior of animals is called innate (ih NAYT)behavior.
A toad captures prey by flipping out its tongue. Tocapture prey, a toad must first be able to detect and follow theprey’s movement. Toads have “insect detector” cells in the retinasof their eyes. As an insect moves across the toad’s line of sight,the “insect detector” cells signal the brain, causing an innateresponse; the toad’s tongue flips out. This is an innate behaviorknown as a fixed-action pattern. A fixed-action pattern is anunchangeable behavior pattern that, once begun, continuesuntil completed.What is the basis of innate behavior?2. What does innate behavior include?________________________________________________________________________Scientists have found that an animal’s hormonal balance andits nervous system affect how sensitive the individual is to certainstimuli.
The sense organs responsible for sight, sound, touch,and odor identification are especially important. In fire antcolonies, a single gene influences the acceptance or rejection ofthe ant queen, thereby controlling the colony’s social structure.Innate behavior includes fixed-action response, automaticresponse, and instincts.3. What controls the fightor-flight response?________________________________________________________________________398Chapter 33What happens if something is thrown at your face? Your firstreaction is to blink and jerk back your head. Even if a protectiveclear shield is placed in front of you, you cannot stop yourselffrom behaving this way.
This reaction is called a reflex, the simplest form of innate behavior. A reflex (REE fleks) is a simple,automatic response to a stimulus that involves no conscious control. If you accidentally touch a hot stove, you will automaticallyjerk your hand away. Before you even have time to think about it,the reflex movement saves your body from serious injury.Another automatic response, called fight-or-flight response,has adaptive value. Think about a time when you were suddenlyscared. Your heart began to beat faster. Your skin got cold andclammy and your breathing rate increased. You were having afight-or-flight response.
A fight-or-flight response mobilizes thebody for greater activity. Your body is being prepared to eitherfight or run from the danger. A fight-or-flight response is automatic and controlled by hormones and the nervous system.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Automatic ResponsesNameDateClassSection33.1Innate Behavior, continuedInstinctive BehaviorCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.The fixed-action response of the toad capturing prey, thereflex response to a hot stove, and the fight-or-flight response arequick, automatic responses to stimuli.
Some behaviors, however,take a longer time because they involve more complex actions.An instinct (IHN stingt) is a complex pattern of innate behavior.Instinctive behavior begins when the animal recognizes a stimulusand continues until all parts of the behavior are completed. Forexample, a female greylag goose instinctively retrieves an egg thatshe sees has rolled out of the nest.Much of an animal’s courtship behavior is instinctive. Courtshipbehavior is the behavior that males and females of a species carryout before mating. Like other instinctive behaviors, courtshiphas evolved through natural selection.
Courtship behavior helpsmembers recognize other members of the same species. That isimportant for the survival of the species. In courtship, behaviorensures that members of the same species find each other andmate. Such behavior has adaptive value for the species. For example, different species of fireflies can be seen at dusk flashing distinct light patterns. Female fireflies of one species respond onlyto those males flashing the species-correct patterns.Some courtship behaviors prevent females from killing malesbefore they have had the opportunity to mate. For example, insome spider species, the male is smaller than the female and risksbeing eaten if he gets close to her. Before mating, the male insome species presents the female with an object, such as an insectwrapped in a silk web.
While the female is unwrapping and eatingthe insect, the male is able to mate with her without being attacked.Sometimes, after mating, the female eats the male anyway.4. How has courtship behavior evolved?________________________________________________________________________Can instinctive behavior reduce aggression?A territory is a physical space an animal defends against othermembers of its species. It may contain the animal’s breeding area,feeding area, potential mates, or all three. Animals that haveterritories will defend their space. They will drive away otherREADING ESSENTIALSChapter 33399NameDateClassSection33.1Innate Behavior, continued5.
What are the benefits ofterritorial behavior?________________________________________________________________________individuals of the same species. For example, a male sea lionpatrols the area of beach where his harem of female sea lions islocated. He does not bother a neighboring male that has a haremof his own. Both males have marked their territories and eachrespects the boundaries.
However, if a young, unattached maletries to enter the sea lion’s territory, the owner of the territorywill attack and drive the intruder away.Setting up territories reduces conflicts, controls populationgrowth, and provides for efficient use of environmental resources.When animals space themselves out, they don’t compete for thesame resources within a limited space. This behavior improvessurvival rates. If the male has selected an appropriate site and theyoung survive, they may have inherited his ability to select anappropriate territory. Territorial behavior has survival value, notonly for individuals, but also for the species.Pheromones are chemicals that communicate informationamong individuals of the same species.
Many animals producepheromones to mark territorial boundaries. For example, wolfurine contains pheromones that warn other wolves to stay away.Pheromones work day and night, and they work whether or notthe animals that made the marks are present.Animals sometimes act aggressively. Aggressive behavior isused to intimidate another animal of the same species. Animalsfight or threaten one another in order to defend their young,their territory, or another resource, such as food.
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