Presentation on theme: "Proximate vs. Ultimate Causes"— Presentation transcript:
1 Ethology is the scientific study of animal behavior, and a sub-topic of zoology.
2 Proximate vs. Ultimate Causes Proximate causes-what mechanism enables the organism to exhibit the behavior?Ultimate causes-in terms of evolution, how and why did that behavior come to be?
3 The “proximate cause” is the immediate trigger for a behavior. For example, if a zebra is drinking at a water hole, and all of a sudden it hears another zebra nearby make an alarm call, it may stop drinking immediately and start running away instead.The “proximate cause” is the immediate trigger for a behavior.The proximate cause of the zebra running away would be the alarm call.But the ultimate cause, or real (evolved) reason why the zebra is running is survival. It is running away because it wants to survive. The alarm call is not the source of danger, but the alarm call alerts the zebra that danger, such as a lion, may be nearby and the lion can threaten the zebra's chance to survive.
4 Another example: The mouthless jellyfish-Mastigias paupua migrates upward in the water column during the day, and descends at night.Proximate Explanation-when the sun rises, the jellyfish switch from infrequent, undirected pulsing of their bells to a clear taxis, directing themselves toward the rising sun and pulsing continuouslyThis directed movement brings them to the surface, where they drift into the sunlight.Although they lack eyes, jellyfish are sensitive to light and are able to orient themselves toward itThis is because electrically coupled, photosensitive neurons control their swimming behavior and can direct the top of the animal toward the sun.Ultimate explanation-Although they are animals, Mastigias sp. do not eat.They are dependent upon photosynthetic algae called zooxanthelle which are imbedded in their tissues.Over millions of years, jellyfish that behaved in such a way as to maximize the photosynthesis of their symbionts left more offspring than others, and ultimately evolved coordinated muscle contractions to ensure that their symbionts had enough light.
5 Innate vs. Learned Behavior Innate behavior is developmentally fixed. Despite differing environments, all individuals that can exhibit the behavior do exhibit the behavior.This does not mean the environment does not play a role, innate behaviors are triggered by a stimulus which must occur within the context of the animals environmentLearned behaviors are modified by experience.There is no hard-and-fast distinction between the two, many learned behaviors have a strongly pre-determined chronology (I.e., language learning) and many innate behaviors are improved by experience (I.e., parasitoid foraging).
6 TAXIS vs KINESISA taxis is an innate behavioral response by an organism to a directional stimulus or gradient of stimulus intensity.A taxis differs from a tropism (“turning response”, often growth towards or away from a stimulus) in that the organism has motility and demonstrates guided movement towards or away from the stimulus source.It is sometimes distinguished from a kinesis, a non-directional change in activity in response to a stimulus.Example: For example, flagellate protozoans of the genus Euglena move towards a light source. Here the directional stimulus is light, and the orientation movement is towards the light. This reaction or behavior is a positive one to light and specifically termed "positive phototaxis”.
7 TAXIS vs KINESISKinesis, like a taxis, is a movement or activity of a cell or an organism in response to a stimulus.However, unlike taxis, the response to the stimulus provided (such as gas exposure, light intensity or ambient temperature) is non-directional.Example: Pillbugs are decreasingly active as humidity increases.
8 Fixed Action PatternsA FAP is a sequence of innate behavioral acts that is essentially unchangeable and usually conducted to completion once it is started.It is triggered by a sensory environmental stimulus called a sign stimulus (or releaser).Because the animal responds to the sign stimulus, rather than the environment as a whole, the animal may be tricked by signals that are out of their usual context.
9 Fixed Action Patterns Example of a FAP: Many mating dances, commonly carried out by birds, are examples of fixed action patterns. In these cases, the sign stimulus is typically the presence of the female.
10 Fixed Action PatternsAnother example of fixed action patterns is aggression towards other males during mating season in the red-bellied stickleback.A series of experiments carried out by Niko Tinbergen showed that the aggressive behavior of the males is a FAP triggered by anything red, the sign stimulus.
11 Fixed Action PatternsAnother well known case is the classic experiments by Tinbergen and Konrad Lorenz on the Graylag Goose.Like similar waterfowl, it will roll a displaced egg near its nest back to the others with its beak.The sight of the displaced egg triggers this mechanism.If the egg is taken away, the animal continues with the behavior, pulling its head back as if an imaginary egg is still being maneuvered by the underside of its beak.However, it will also attempt to move other egg shaped objects, such as a golf ball, door knob, or even an egg too large to have possibly been laid by the goose itself.
12 All behaviors are influenced by both genes and the environment The extent to which genes control the manifestation of a behavior differs from one behavior to the next.Example: Alcoholism can actually be broken into two behaviors; teen-onset alcoholism and adult-onset alcoholism.Cross-fostering studies using children placed in foster homes indicate that teen onset alcoholism has a very strong genetic basis.The same studies indicate that adult-onset alcoholism has a stronger environmental basis.All genes, including those whose expression underlies an innate behavior, require an environment to be expressed.If the same study had been conducted in Saudi Arabia, there may have been no alcoholics at all (strong cultural reasons not to drink, and alcohol less readily available).
13 Example of Genetic Variation for a Behavior-Roving vs. Sitting Some behavioral differences are known to be caused by variation at a single gene.In the fruit fly, Drosophila melanogaster, larvae exhibit two different behaviors.“Rovers” crawl around constantly, moving several centimeters after feeding in a particular location.“Sitters” basically stay put.The two different behaviors are found in natural populations, as well as in laboratory strains.By isolating rovers and sitters, it was possible to breed pure strains for the two behaviors.
14 LearningLearning can be defined as a more or less permanent change in the behavior or potential behavior of an animal based upon experience.Learning is pervasive in the behavior of birds and mammals, but other animals are capable of learning as well.Example; learning in the sea anemone Stomphia sp. Chemostimulation, paired with mechanical pressure, will cause a sea anemone to detach and swim off. With repeated trials, pressure alone will cause the anemone to detach itself. YouTube video
15 Simple non-associative learning Habituation is the relatively persistent waning of a response to a stimulus when the expected result does not occur.Sensory Adaptation is sometimes called habituation, it is the phenomenon where environmental noise is filtered out by the nervous system over time and the animal no longer responds to it.Sensitization is the growing sensitivity of an animal to repeated stimuli. In essence, it is the opposite of sensory adaptation-it occurs when the stimulus is rewarded or is of adaptive significance.A search image is an image an animal becomes especially adept at recognizing, as a result of repeatedly searching for it and being rewarded for finding it.
16 Associative LearningThese are processes by which an animal comes to associate events in its environment with consequences or objects with stimuli.Associative learning is the process by which an association between two stimuli or a behavior and a stimulus is learned. The two forms of associative learning are classical and operant conditioning.
17 Classical (Pavlovian) conditioning involves strengthening of the stimulus-outcome association. Classical conditioning (also Pavlovian conditioning or respondent conditioning) is a form of learning in which one stimulus, the conditioned stimulus or CS, comes to signal the occurrence of a second stimulus, the unconditioned stimulus or US.The US is usually a biologically significant stimulus such as food or pain that elicits a response from the start; this is called the unconditioned response or UR.The CS usually produces no particular response at first, but after conditioning it elicits the conditioned response or CR.
18 Ex: R. Menzel- associative learning in honeybees Bees were trained to enter restraining tubes.Sugar water was offered as a CSthe orienting response is an extension of the proboscis by the bee.A variety of smells and colors were offered as US.Bees could learn to associate a variety of smells and colors with sugar water-i.e., they would eventually extend their proboscis in the absence of the sugar water
19 Operant conditioning is the use of consequences (reinforcement/punishment ) to modify the occurrence and form of behavior.In Operant conditioning, the behavior emitted by the organism is strengthened or weakened by its consequences (e.g. reward or punishment).1. Reinforcing a voluntary behavior. Positive reinforcement: A child receives a 'gold star' at school for behaving well.2. Negative reinforcement: A child does his or her homework to stop her parents from nagging. Punishment: Grounding a child for behaving inappropriately
20 EX: Operant conditioning EX: Skinner Box. An operant conditioning chamber permits experimenters to study behavior conditioning (training) by teaching a subject animal to perform certain actions (like pressing a lever) in response to specific stimuli, like a light or sound signal.When the subject correctly performs the behavior, the chamber mechanism delivers food or another reward.In some cases, the mechanism delivers a punishment for incorrect or missing responses.With this apparatus, experimenters perform studies in conditioning and training through reward/punishment mechanisms.
22 QUIZ: http://www.ar.cc.mn.us/biederman/courses/p1110/conditioning2.htm Classical and Operant Conditioning Examples:1. Every time someone flushes a toilet in the apartment building, the shower becomes very hot and causes the person to jump back. Over time, the person begins to jump back automatically after hearing the flush, before the water temperature changes.Answer to Example 12. Your father gives you a credit card at the end of your first year in college because you did so well. As a result, your grades continue to get better in your second year.Answer to Example 23. Your car has a red, flashing light that blinks annoyingly if you start the car without buckling the seat belt. You become less likely to start the car without buckling the seat belt.Answer to Example 34. You eat a new food and then get sick because of the flu. However, you develop a dislike for the food and feel nauseated whenever you smell it.Answer to Example 45. An individual receives frequent injections of drugs, which are administered in a small examination room at a clinic. The drug itself causes increased heart rate but after several trips to the clinic, simply being in a small room causes an increased heart rate.Answer to Example 56. A lion in a circus learns to stand up on a chair and jump through a hoop to receive a food treat.Answer to Example 67. A professor has a policy of exempting students from the final exam if they maintain perfect attendance during the quarter. His students’ attendance increases dramatically.Answer to Example 78. You check the coin return slot on a pay telephone and find a quarter. You find yourself checking other telephones over the next few days.Answer to Example 89. Your hands are cold so you put your gloves on. In the future, you are more likely to put gloves on when it’s cold.Answer to Example 910. John Watson conducted an experiment with a boy named Albert in which he paired a white rat with a loud, startling noise. Albert now becomes startled at the sight of the white rat.Answer to Example 10
23 ImprintingImprinting occurs when an animal learns to make a particular response to a particular object.Process is very rapid.Can be altered, but the usual pattern is an instantaneous and irreversible alteration of behavior.Konrad Lorenz
24 CognitionThe extent to which animals ”think” is unknown, although it is becoming increasingly obvious that the human mind differs from those of other animals largely by the extent of our cognitive ability, rather than the simple rule humans think, animals don’t.Some hallmarks of cognitive abilityability to classifyability to recognize attributes of objectsability to countability to remember the locations of objects in spaceability to use language
25 Some animals for which cognitive ability has been studied Parrots-classification, recognition of attributes, and languageBees, Chimps, Gorillas, Various Monkeys, Hyenas-LanguageAnts, Bees, Ravens, Various Other Birds-Spatial Mapping.Ex: honeybees “waggle dance” NatGeo video
26 PLAYMost mammals, some birds, and possibly some other animals (including elephant-nosed fish) exhibit play behavior.Play is an inexact term that covers a range of behaviors exhibited by young animals.1) social play-such as wrestling and chasing other animals2) exercise play-such as running, hanging from tree limbs, etc..3) object oriented play-involves manipulating a novel objectThe most obvious thing these behaviors have in common is that they have no immediate adaptive value.
27 Functions of PlayIt is frequently hypothesized that the function of play behaviors is to practice adult activities in a context where the consequences of failure are not serious or fatal.Ex: kittens playing with toys, wrestling with each otherEstablish their relative positions in the dominance hierarchy
28 Other Kinds of Behavior kinesis (moves more/less in response to stimulus) and taxis (moves to/away from stimulus)cognitive maps- animal uses cognition to take shortest trip, to plan shortest route, or to remember location of objects.use of landmarks- animal orients behavior patterns to objects in the environmentmigration- seasonal movement of individuals or whole populationsdormancy- seasonal or environmentally induced slowdown of metabolismantipredator behavior/ predatory behaviorcourtshipsocial behaviorsagonistic behaviors-aggressive interactionscooperative foragingcommunication
29 References, credits:University of Illinois, Chicago