BZ 300 1st Edition Lecture 4 Outline of Last LectureI. Single gene effectsII. Evolution and BehaviorIII. Bees expressing Hygienic behaviorIV. Evolution and BehaviorV. SwiftletsVI. Multigenic Effects:VII. Cross-fostering experimentsVIII. Twin/Adoption StudiesIX. Artificial SelectionX. Single Gene MutationsXI. Quantitative GeneticsXII. VarianceXIII. HeritabilityXIV. Parent Offspring RegressionXV. Polygenic ControlXVI. EpistasisXVII. The Puzzle of Consistent BehaviorOutline of Current Lecture I. HomeostasisII. Drive TheoryIII. Behavior regulationIV. Displacement BehaviorV. Redirected BehaviorVI. Self Directed BehaviorVII. Biological Rhythms VIII. DefinitionsIX. Properties of Biological RhythmsX. Types of Biological RhythmsXI. EvidenceCurrent LectureHomeostasis: Drive theory is the internal motion in the body, used in assessing stress and welfare. Not testable and cannot be proven, but has yielded important concepts about behavior. The drive theory asks us to imagine a source of internal energy. Homeostasis comes into play whenever it is related to behavior regulation. The drive then gets reflected in the behavior.Behavioral regulation is the gateway between the external world and the internal world. Behavior is a way to regulate the internal state. Must require a feedback loop. The drive theory is out of fashion but yields concepts important to welfare. The notion of drive is useful but is fuzzy around the edges and cannot be measured. But through behavior regulation, we can measure the stress caused by behaviors. The hydraulic model is the idea that energy builds up to a certain threshold and a behavior kicksin and releases the energy back to a non-motivated state. Similar to the energy of the water when flushing a toilet.How do you dissipate the build up of energy? Behaviors cannot always be in the same direction, can have conflicting drives. Animals can be both fascinated and afraid of a situation. Some behaviors can be hypothesized to indicate stress, which is important for assessing welfare. All behaviors are related to homeostasis and the internal state of the animal. There are three types of behaviors indicating stress:Displacement behavior occurs when an animal performs an act that is irrelevant to the context it is in. An animal tries to do two exclusive things but cannot, thus creating stress and resulting in an irrelevant behavior. Ex. Grooming behaviors in an odd situation that is irrelevant, likely to displace a stressful situation. Redirected behavior happens in similar conditions to displacement. Usually aggressive, cannot be targeted towards directed object, so is redirected to another object. The drives are conflicting, so the aggression is redirected. Much of any aggression is a result of a frightened, stress animal.Self-Directed behavior (SDB) is when animals perform behaviors on themselves, without involving other animals, as a result of stress. Different from displacement behavior because it does not have to be included in the action or situation, simply a result from the stress created. Can SDBs be tools for measuring stress?Stress is decreased, if the behavior is stopped. When the stress is mitigated, behavior will change. Physical effects, low growth, high blood pressure are all useful measures for measuring stress. High level of the hormone corticosteroids are released in stressful situations, similar to those released in fight or flight scenarios.By changing the source of stress, there should be a change in behavior. Examples in changing the source of the stress would be: habitat enrichment, hunting, opportunities to play, remove source of stress, provide a social environment.Medication? Many of the stress medications, anxiety, and depression used in humans, can be used in animals as well. Although they have positive effects in decreasing stress, the same drugsmay increase aggression. Biological Rhythms occur when animal activities and behavioral patterns can be directly related to environmental factors that are predictably frequent. These changes in behavior throughoutthe day are both the manifestation by the biological clock and are regulated by it. Definitions to know for biological rhythms:Biological clocks- internal timing mechanism that is a self sustaining physiological pace maker that gives it a general rhythm and synchronizer in order to fine tune the rhythm and to stay in touch with environmental stimuli. Zeitgeger (time giver)- external cue to reset the biological clock, and keep they rhythm regular and in tune to what is going on outside the body, oftentimes light.Cycles- repeating unit that composes the biological rhythm.Period- length of time required to complete the cycle.Amplitude-difference between peak of the trough or valley of the cycle when graphed.Phase- certain part of a cycle of the period that is recognizable. This can have either an active orsedentary phase.Free-running rhythm- the rhythm addressed with absence of the cue (Zeitgeger). The cue is necessary to keep it on the cycle, without the cue it may not stay in rhythm.Properties of biological rhythms: They are temperature compensated, insensitive to temperature and do not change regardless ofhot or cold. Daily rhythm and patterns are unaffected by metabolic poisons and inhibitors.Occurs along with one or more regular features of the environment. Circa is Latin for approximately and is the root for many types of Biological Rhythms. Biological rhythms are self sustaining and continuous in the absence of other features. They can also be entrained, set and adjusted by some form of outside influences. Types of Biological Rhythms:Epicycles (ultradian)- very short durations, not well understood. Happens often with specific worms. Tidal- Exhibit twelve hour rhythms between the tidal phase, main psychological rhythms will be affected by the tides going in and out. Salinity levels and other features linked with tides affect mating and feeding in specifically marine animals.Lunar- affected by cycle of the moon, which is 29 days. A lot of insects will pupalate at the end of the lunar cycle. Related to the tidal rhythms. Circadian rhythm- affects most animals, generally 24 hours in duration. Circadian rhythms are governed by a self-sustaining pacemaker. Diurnal is the peak activity of any system or behavior during the day, this is affected by available light not necessary sunlight. Nocturnal is referred to animals peak activity occurring during the night. Crepuscular is referred to