5 Steps to a 5: AP Biology 2017 (2016)
Review the Knowledge You Need to Score High
Behavioral Ecology and Ethology
IN THIS CHAPTER
Summary: This chapter focuses on the interaction between animals and their environments (ecology) and introduces you to some of the basic terms used in behavioral ecology and ethology.
Learn the bold-faced terms in this chapter well because they show up often on the multiple-choice portion of the exam.
Types of animal learning: associative learning, fixed-action pattern, habituation, imprinting, insight learning, observational learning, and operant conditioning.
Three major types of animal movement: kinesis, migration, and taxis.
Behavioral patterns/concepts to know: agonistic behaviors, altruistic behaviors, coefficient of relatedness, dominance hierarchies, foraging, inclusive fitness, optimal foraging, reciprocal altruism, and territoriality.
Types of animal communication: chemical, visual, auditory, and tactile.
Behavioral ecology and ethology both involve the study of animal behavior. Behavioral ecology focuses on the interaction between animals and their environments, and usually includes an evolutionary perspective. For example, a behavioral ecologist might ask, “Why do two bird species that live in the same environment eat two different types of seeds?” Ethology is a narrower field, focused particularly on animal behavior and less on ecological analysis. Historically, ethology has involved a lot of experimental work, which has given us insight into the nature of animal minds.
CT teacher: “This chapter has a lot of multiple-choice-type questions in it. Learn the general concepts. . . .”
This chapter introduces you to some of the basic terms and concepts used in behavioral ecology and ethology.
Types of Animal Learning
Associative learning is the process by which animals take one stimulus and associate it with another. Ivan Pavlov demonstrated classical conditioning, a type of associative learning, with dogs. As will come to be a pattern in this chapter, some poor animals were tampered with to help us understand an important biological principle. Pavlov taught dogs to anticipate the arrival of food with the sound of a bell. He hooked up these dogs to machines that measured salivation. He began the experiments by ringing a bell just moments before giving food to the dogs. Soon after this experiment began, the dogs were salivating at the sound of the bell before food was even brought into the room. They were conditioned to associate the noise of the bell with the impending arrival of food; one stimulus was substituted for another to evoke the same response.
A fixed-action pattern (FAP) is an innate, preprogrammed response to a stimulus. Once this action has begun, it will not stop until it has run its course. For example, male stickleback fish are programmed to attack any red-bellied fish that come into their territory. Males do not attack fish lacking this red coloration; it is specifically the color that stimulates aggressiveness. If fake fish with red bottoms are placed in water containing these stickleback fish, there’s bound to be a fight! But if fake fish lacking a red bottom are dropped in, all is peaceful.
Habituation is the loss of responsiveness to unimportant stimuli. For example, as one of us started working on this book, he had just purchased a new fish tank for his office and was struck by how audible the sound of the tank’s filter was. As he sits here typing tonight about two months later, he does not even hear the filter unless he thinks about it; he has become habituated to the noise. There are many examples of habituation in ethology. One classic example involves little ducklings that run for cover whenever birdlike objects fly overhead. If one were to torture these poor baby ducks and throw bird-shaped objects over their heads, in the beginning they would head for cover each time one flew past them, but over time as they learned that the fake birds did not represent any real danger, they would habituate to the mean trick and eventually not react at all. One side note is that ethologists who study wild animals usually have to habituate their study subjects to their presence before recording any behavioral data.
Imprinting is an innate behavior that is learned during a critical period early in life. For example, when geese are born, they imprint on motion that moves away from them, and they follow it around accepting it as their mother. This motion can be the baby’s actual mother goose, it can be a human, or it can be an object. Once this imprint is made, it is irreversible. If given an essay about behavioral ecology, and imprinting in particular, the work of Konrad Lorenz would be a nice addition to your response. He was a scientist who became the “mother” to a group of young geese. He made sure that he was around the baby geese as they hatched and spent the critical period with them creating that mother–baby goose bond. These geese proceeded to follow him around everywhere and didn’t recognize their real mother as their own.
Insight learning is the ability to do something right the first time with no prior experience. It requires reasoning ability—the skill to look at a problem and come up with an appropriate solution.
Observational learning is the ability of an organism to learn how to do something by watching another individual do it first, even if they have never attempted it themselves. An example of this involves young chimpanzees in the Ivory Coast, who watch their mothers crack nuts with rock tools before learning the technique themselves.
Operant conditioning is a type of associative learning that is based on trial and error. This is different from classical conditioning because in operant conditioning, the association is made between the animal’s own behavior and a response. This is the type of conditioning that is important to the aposometrically colored organisms that we discuss in Chapter 18 on ecology. For example, a brightly colored lizard with a chemical defense mechanism (it can spray predators in an attempt to escape) relies on this type of conditioning for survival. The coloration pattern is there in the hope that the predator will, in a trial-and-error fashion, associate the coloration pattern with an uncomfortable chemical-spraying experience that it had in the past. This association might make the predator think twice before attacking in the future and provide the prey with enough time to escape.
There are three major types of animal movement that you should familiarize yourself with for the AP exam: kinesis, migration, and taxis.
Kinesis . This is a seemingly random change in the speed of a movement in response to a stimulus. When an organism is in a place that it enjoys, it slows down, and when in a bad environment, it speeds up. Overall this leads to an organism spending more time in favorable environments. In Chapter 19 , Laboratory Review, an example of kinesis involving pill bugs is discussed. These bugs prefer damp environments to dry ones, and when placed into a contraption that gives them the choice of being on the dry or damp side, they move quickly toward the damp side (where the speed of their movement slows).
Migration . This is a cyclic movement of animals over long distances according to the time of year. Birds are known to migrate south, where it is warmer, for the winter. It is amazing that these animals know where to go.
Taxis . These are cars taken by people who need transportation. Hmm . . . actually, taxis, the biological term, is a reflex movement toward or away from a stimulus. We always think about summer evenings, sitting on the porch with the bug light near by, watching the poor little moths fly right into the darn thing because of the taxis response. They are drawn to the light at night (phototaxis ).
BIG IDEA 2.E.3
Behaviors (such as migration) are regulated by various mechanisms and are important to natural selection .
Behave Yourselves, You Animals!
There are several typical behavior patterns that you should familiarize yourself with before the exam.
1. Agonistic behavior. Behavior that results from conflicts over resources. It often involves intimidation and submission. The battle is often a matter of who can put on the most threatening display to scare the other one into giving up, although the displays can also be quite subtle. Agonistic behaviors can involve food, mates, and territory, to name only a few. Participants in these displays do not tend to come away injured because most of these interactions are just that: displays.
2. Altruistic behavior. An altruistic action is one in which an organism does something to help another, even if it comes at its own expense. An example of this behavior involves bees. Worker bees are sterile, produce no offspring, and play the role of hive defenders, sacrificing their lives by stinging intruders that pose a threat to the queen bee. (Sounds to us like they need a better agent.) Another example involves vampire bats that vomit food for group mates that did not manage to find food.
3. Coefficient of relatedness. This statistic represents the average proportion of genes that two individuals have in common. Siblings have a coefficient of relatedness (COR) of 0.5 because they share 50 percent of their genes. This coefficient is an interesting statistic because it can be expected that an animal that has a high COR with another animal will be more likely to act in an altruistic manner toward that animal.
4. Dominance hierarchies. A dominance hierarchy among a group of individuals is a ranking of power among the members. The member with the most power is the “alpha” member. The second-in-command, the “beta” member, dominates everyone in the group except for the alpha. It pretty much rocks to be at the top of the dominance hierarchy because you have first dibs (choice) on every thing (food, mates, etc.). The dominance hierarchy is not necessarily permanent—there can always be some shuffling around. For example, in chimpanzees, an alpha male can lose his alpha status and become subordinate to another chimp if power relationships change. One positive thing about these hierarchies is that since there is an order, known by all involved, it reduces the energy wasted and the risk from physical fighting for resources. Animals that know that they would be attacked if they took food before a higher-ranking individual wait until it is their turn to eat so as to avoid conflict. Keep in mind that dominance hierarchies are a characteristic of group-living animals.
5. Foraging. A word that describes the feeding behavior of an individual. This behavior is not as random as it may seem as animals tend to have something called a search image that directs them toward their potential meal. When searching for food, few fish look for a particular food; rather, they are looking for objects of a particular size that seem to match the size of what they usually eat. This is a search image. In an aquarium at mealtime, if you watch the fish closely, you will see them zoom around taking food into their mouths as they swim. Unfortunately, sometimes the “food” they ingest is the bathroom output of another fish that happens to be the same size as the food and is floating nearby. Simply because the fish dropping is the appropriate size and fits the search image, the fish may take it into its mouth for a second before emphatically spitting it out.
6. Inclusive fitness. This term represents the overall ability of individuals to pass their genes on to the next generation. This includes their ability to pass their own genes through reproduction as well as the ability of their relatives to do the same. Reproduction by relatives is included because related individuals share many of the same genes. Therefore, helping relatives to increase the success of passage of their genes to the next generation increases the inclusive fitness of the helper. The concept of inclusive fitness can explain many cases of altruism in nature.
7. Optimal foraging. Natural selection favors animals that choose foraging strategies that take into account costs and benefits. For example, food that is rich in nutrients but far away may cost too much energy to be worth the extra trip. There are many potential costs to traveling a long distance for some food—the animal itself could be eaten on the way to the food, and the animal could expend more energy than it would gain from the food. You know that you have displayed optimal foraging behavior before. “Hey, do you want to go to Wendy’s?” “Uhh . . . not really, it’s a really long drive . . . let’s go to Bill’s Burgers down the road instead.”
8. Reciprocal altruism. Why should individuals behave altruistically? One reason may be the hope that in the future, the companion will return the favor. A baboon may defend an unrelated companion in a fight, or perhaps a wolf will offer food to another wolf that shares no relation. Animals rarely display this behavior since it is limited to species with stable social groups that allow for exchanges of this nature. The bats described earlier represent a good example of reciprocal altruism.
9. Territoriality. Territorial individuals defend a physical geographic area against other individuals. This area is defended because of the benefits derived from it, which may include available mates, food resources, and high-quality breeding sites. An individual may defend a territory using scent marking, vocalizations that warn other individuals to stay away, or actual physical force against intruders. Animal species vary in their degree of territoriality (in fact, some species are not territorial), and both males and females may exhibit territorial behavior.
Animals communicate in many ways. Communication need not always be vocal, and we will discuss the various communication mechanisms in this next section: visual, auditory, chemical, and tactile.
Chemical communication . Mammals and insects use chemical signals called pheromones, which in many species play a pivotal role in the mating game. Pheromones can be powerful enough to attract mates from miles away.
BIG IDEA 3.D.1
Communication can involve signals from other organisms or the environment .
Visual communication . We mentioned a few visual communication examples earlier, such as agonistic displays. Another example of a visual display is a male peacock’s feather splay, which announces his willingness to mate.
Auditory communication . This mode of communication involves the use of sound in the conveying of a message. In many parts of the United States, if one sits on one’s porch on a summer night, one hears the song of night frogs and crickets. These noises are often made in an effort to attract mates.
Tactile communication . This mode of communication involves touch in the conveying of a message and is often used as a greeting (handshake in humans). A major form of primate tactile communication involves grooming behavior.
BIG IDEA 3.E.1
Individuals can act on information and communicate it to others .
Bees provide an example of communication that involves chemical, tactile, and auditory components. The beehive is a dark and crowded place, and when a worker bee returns after having found a good food source, how in the world is it going to get the attention of all of the co-workers? Unfortunately, intercom systems in hives are yet to be developed. What these bees do instead is a little dance; a dance in a tight circle accompanied by a certain wag signifies to the co-workers “Hey guys . . . food source is right down the street.” But if the food is farther away, the bee changes the dance to one that provides directional clues as well. The bee will instead perform a different combination of funky moves. This dance provides distance and directional information to the other workers and helps them find the faraway source. The ever so pleasant chemical component to this process is the regurgitation of the food source to show the other bees what kind of food they are chasing. Imagine if humans did that . . . “Dude, I just found the greatest burger place like two miles from here . . . (burp) here . . . try this burger . . . it’s delightful!”
1 . When horses hear an unusual noise, they turn their ears toward the sound. This is an example of
A. a fixed-action pattern.
C. associative learning.
2 . Why do animal behaviorists have to account for a habituation period when undertaking an observational study?
A. They have to make sure that the study animals do not imprint on them.
B. They have to wait until their presence no longer affects the behavior of the animals.
C. The animals need a period of time to learn to associate the observer with data collection.
D. Before insight learning can be observed, the animals must practice.
E. The animals must remain cautious of the observer at all times.
3 . Which of the following is an example of an agonistic behavior?
A. A subordinate chimpanzee grooms a dominant chimpanzee.
B. Two lionesses share a fresh kill.
C. A female wolf regurgitates food for her nieces and nephews.
D. A blackbird approaches and takes the feeding position of another blackbird, causing it to fly away.
E. Two fish in a stream pass each other without changing course.
4 . In which of the following dyads do we expect not to see any altruistic behavior?
A. Two sisters who are allies
B. Two half-brothers
C. Two individuals migrating in opposite directions
D. Two group members who have frequent conflicts and reconciliations
E. Two adolescents who are likely to eventually transfer into the same group
5 . Which of the following is not a requirement for reciprocal altruism to occur?
A. Ability to recognize the other individual
B. Long lifespan
C. Opportunity for multiple interactions
D. Good long-term memory
E. High coefficient of relatedness
6 . A female tamarin monkey licks her wrists, rubs them together, and then rubs them against a nearby tree. What kind of communication is this probably an example of?
For questions 7–10, please use the following answers:
A. Fixed-action pattern
D. Associative learning
E. Operant conditioning
7 . This type of learning is the lack of responsiveness to unimportant stimuli that do not provide appropriate feedback.
8 . Trial-and-error learning important to animals displaying aposometric coloration.
9 . Process by which animals associate one stimulus with another.
10 . Innate behavior that is learned during a critical period in life.
Answers and Explanations
1 . A —This is a fixed-action pattern—an innate behavior that is a programmed response to a stimulus that appears to be carried out without any thought by the organisms involved.
2 . B —If the scientist does not allow for a period of habituation, the behavioral observations will be inaccurate since the behavior of the animal will be altered by the presence of the scientist.
3 . D —An agonistic behavior is a contest of intimidation and submission where the prize is a desired resource. In this case, the resource is the feeding position.
4 . C —Altruistic behavior cannot be expected from two migrating individuals for a couple of reasons: (a) there is no reason for either of them to believe that they will see the other in the future, taking the “If I help them now, perhaps they will help me sometime in the future” element out of play; and (2) if they are migrating in different directions, it is reasonably likely that they are probably not related, which takes the “I’ll help because it’ll increase the chance that more of my genes get passed along” element out of play.
5 . E —Reciprocal altruism need not occur between related individuals.
6 . A
7 . B
8 . E
9 . D
10 . C
Quickly review the following terms:
Behavioral ecology: study of interaction between animals and their environments.
Ethology: study of animal behavior.
Types of Animal Learning
• Fixed-action pattern: preprogrammed response to a stimulus (stickleback fish).
• Habituation: loss of responsiveness to unimportant stimuli or stimuli that provide no feedback.
• Imprinting: innate behavior learned during critical period early in life (baby ducks imprint to mama ducks).
• Associative learning: one stimulus is associated with another (classical conditioning—Pavlov).
• Operant conditioning: trial-and-error learning (aposometric predator training).
• Insight learning: ability to reason through a problem the first time through with no prior experience.
• Observational learning: learning by watching someone else do it first.
Types of Animal Movement
• Kinesis: change in the speed of movement in response to a stimulus. Organisms will move faster in bad environments and slower in good environments.
• Migration: cyclic movement of animals over long distances according to the time of year.
• Taxis: reflex movement toward or away from a stimulus.
• Agonistic conflict behavior over access to a resource. Often a matter of which animal can mount the most threatening display and scare the other into submission.
• Dominance hierarchies: ranking of power among the members of a group; subject to change. Since members of the group know the order, less energy is wasted in conflicts over food and resources.
• Territoriality: defense of territory to keep others out.
• Altruistic action in which an organism helps another at its own expense.
• Reciprocal altruism: animals behave altruistically toward others who are not relatives, hoping that the favor will be returned sometime in the future.
• Foraging: feeding behavior of an individual. Animals have a search image that directs them to food.
• Optimal foraging: natural selection favors those who choose foraging strategies that maximize the differential between costs and benefits. If the effort involved in obtaining food outweighs the nutritive value of the food, forget about it.
• Inclusive fitness: the ability of individuals to pass their genes not only through the production of their own offspring, but also by providing aid to enable closely related individuals to produce offspring.
• Coefficient of relatedness: statistic that represents the average proportion of genes two individuals have in common. The higher the value, the more likely they are to altruistically aid one another.
• Chemical: communication through the use of chemical signals, such as pheromones.
• Visual: communication through the use of visual cues, such as the tail feather displays of peacocks.
• Auditory: communication through the use of sound, such as the chirping of frogs in the summer.
• Tactile: communication through the use of touch, such as a handshake in humans.
Behavioral Ecology and Ethology
1 . If a greylag goose’s egg becomes displaced from the nest, the greylag rolls it back to the nest with its beak. If the egg is removed from the goose during the performance of egg-rolling, the bird often continues with the behavior, pulling its head back as if an imaginary egg is still being maneuvered by the underside of its beak. The greylag will also attempt to retrieve other egg-shaped objects, such as a golf ball, doorknob, or even a model egg too large to have possibly been laid by the goose itself. This is an example of which of the following types of animal learning?
(C) Fixed-action pattern
(D) Operant conditioning
2 . Which type of behavior results from conflicts over resources?
(A) Agonistic behavior
(B) Altruistic behavior
3 . Which of the following represents the overall ability of an individual to pass his or her genes along to the next generation?
(A) The coefficient of relatedness
(B) Inclusive fitness
(C) Genetic power
(D) Hereditary efficiency
4 . An action in which one organism helps another, even if it comes at its own expense, is known as
(A) associative learning.
(B) optimal foraging.
(C) altruistic behavior.
(D) agonistic behavior.
Answers and Explanations
1 . C —This is a classic example of a fixed-action pattern, which is a preprogrammed response to a stimulus.
2 . A —Agonistic behaviors often involve intimidation and submission. The battle is often a matter of who can put on the most threatening display to scare opponents into giving up, although the displays can also be quite subtle. Agonistic behaviors can involve food, mates, and territory. Participants in these displays do not tend to come away injured because most of the interactions are just displays.
3 . B —Inclusive fitness involves an individual’s ability to pass his or her own genes along through reproduction, as well as the ability of the individual’s relatives to do the same. Genetic power and hereditary efficiency sound fancy, but they are not real terms. The coefficient of relatedness is a statistic used to represent the average proportion of genes that two individuals have in common.