Exam 1

Question 0

Scientific approaches to animal behavior

Answer 0

– Inside the skin: physiologists study the machinery of behavior. Nervous system, endocrine system, skeleto-muscular system.
– Outside the skin approach: comparative psychologists – lab oriented; use a few species to formulate general rules. Ethologists– study behavior in the wild. Behavioral ecologist – study behavioral interactions among animals and interactions between animals and their environment

Question 1

What is behavior?

Answer 1

Any sort of reaction to stimuli

Question 2

Why study animal behavior?

Answer 2

– Wildlife management/conservation
– Improves understanding/care for domesticated/companion animals/ourselves
– Improves understanding of biological principles such as natural selection, community ecology, etc.

Question 3

Konrad Lorenz

Answer 3

Discovered principle of imprinting

Question 4

Niko Tinbergen

Answer 4

With Lorenz, founded ethology, the scientific study of animal behavior in nature

Question 5

Carl von Frisch

Answer 5

Animal communication (honeybees)

Question 6

Jacob von Uexkull

Answer 6

– Animals experience umvelten (perceptual worlds) Different from us and from each other. For example, insects/birds see ultraviolet wavelengths. Elephants here infra sound

Question 7

Charles Darwin

Answer 7

– Theory of natural selection: no two individuals alike, some of this variation has heritable basis from alternative alleles.
– – Offspring are overproduce, strongest survive through competition, predation, climate, disease – all are selective pressures
– Some offspring have heritable traits that confers survival and reproductive advantages.
– – These traits become more prevalent in populations over time and individuals carrying less advantageous traits are removed
– Natural selection produces adaptations: traits that enhance an individuals ability to survive and reproduce in its environment

Question 8

Fitness

Answer 8

Lifetime reproductive success. Ability to contribute genes to next generation. Measured by: lifetime production of viable offspring. Unit of selection: the individual

Question 9

First observational experiment in ethology

Answer 9

– The Bee wolf

- Timbergen used subtle environmental manipulation to figure out how bee wolfs find their burrow in the burrow field

Question 10

Tinbergens 4 questions

Answer 10

Defined research process to determine what animals are doing and why.

1. Causation - (Proximate question – anything relating to it is a proximate explanation) (ex-Physiological explanation) Example for bee wolves, proximate explanation would be that bee wolves use landmarks to find burrows
2. Development (ontogeny). (Proximate question) Physical process. Behaviors can develop and particular ways in a species/individual. Example: when do be wolves begin doing it? Does it involve a particular hormone during a certain stage of development? Isn’t learned or innate?
3. Function (Ultimate question/explanation) Does it advance reproductive sexcess? Play a role in feeding, defense, mate attraction?
4. Evolution (phylogeny) ( Ultimate question) Deeper questions – through what evolution process did this behavior arise? Did behavior originally arise under natural selection and then co-opted for other purpose other than the original one?

Question 11

How do you get at an animals behavior at all levels guided by Tinbergens 4 questions

Answer 11

Ex - prairie voles are monogamous why?

In the central palladium of the male vile, there is a high concentration of receptors for hormone that helps them to feel “warm and fuzzy” after mating, to feel attachment to mate. “Reward center”

• -why is this? Prairie voles have gene erosion of avpr1a that up-regulates these receptors (transcribes more of these receptors - makes them respond more even when very little of the hormone is present, makes them more sensitive to it)
• -can make predictions based on this
• –ex: if extra copies of this gene are introduced to central palladium and different parts of the brain and measured how often voles spend time with own mate vs. a strange female. Voles with extra copy in central palladium (with up-regulation) showed difference, ones in different part had no effect.
• —resulted in exaggerated version of behavior vs. control gene in same area or same gene in diff area
• —did same thing for a diff non-monogamous species and got same results
• —this is a proximate explanation to determine what the gene does and how it produces the reinforcement for the males to stay with their mates - proximate stimulus.
• Deeper evolutionary question: infanticide occurs often in rodents as well. But not in Prairie voles. Could it be a result of this behavior/reduce infanticide and increase odds of your own offspring surviving?

Question 12

Fixed action patterns

Answer 12

Innate, stereotyped (Done the same way by everyone in population/species) Behaviors carried through to completion once triggered without any prior experience (Lorenz and Tinbergen)

• –Today called modal action patterns
• –Stimulated by simple key stimuli

Question 13

Proximate causation: stimuli. First ethologists studied instinctive behavior

Answer 13

– Example: geese egg rolling eggs back into nests. Do geese know that’s their egg/what they’re doing?
– Example: red breasts in male European Robin triggers aggression and other male robins. What’s the stimulus that’s most important to the Robin? Is it just the red, or do they know they’re responding to another male?

Question 14

Sign stimuli (SS)

Answer 14

– External stimuli that triggers FAP’s. Also called “releasers”.
– Example: reflexive pecking behavior in black backed gull chicks, who pack at red dot on parents beaks to trigger regurgitation.

Question 15

Rove beetle

Answer 15

Ants use tactile cues to communicate with other ants; can tap on other aunts mouthparts to get food from other ants. Rove beetles use the signal to get ants to regurgitate food for them in the same manner – controlled the stimuli to get response.

Question 16

Supernormal stimuli

Answer 16

Exaggerated sign or stimuli or releasers. When presented with exaggerated stimulus, animals will preferentially respond to it. Built in bias from nervous system. Can explain brood parasitism in birds/flashiness and males

Question 17

Effects of sign stimuli on behavior

Answer 17

• elicit (triggers behavior)
• maintain
• orient
• inhibit

Question 18

Innate releasing mechanism (IRM)

Answer 18

• Internal decision-maker located somewhere in nervous system
• Sign stimuli –> innate release mechanism –> fixed action pattern

– – However, animals don’t always respond to sign stimuli in their environments. Example: stickleback fish. Redbelly ask as releasor only during mating season. Will responds to read because during mating season when males are defending territories, they develop a bright red stomach. Only reacts to redbelly during mating season, not outside of it when not defending territory

Question 19

What explains animals changing motivations

Answer 19

– FAP’s may also occur in absence of SS or vice versa
– – Lorenz’s theory: Action specific energy (ASE). Builds up as time you lapses since last performance of behavior. Lowers animals threshold of response to releasers. Example: if go a long time without eating, will devour food.

• now we know it has to do with homeostatic model

Question 20

Homeostatic model

Answer 20

– Negative feedback: Corrects deviation from homeostatic setpoints
– stimulus -> receptor -> integrator (brain control centers such as the hypothalamus) (comparison with “set point”) -> appetitive (ex-water seeking), consummatory behaviors (ex- drinking that returns body to set point) -> back to beginning (stimulus, etc)
– It is a negative feedback because no matter which way things deviate, body must correct back to set point

Question 21

Internal stimuli

Answer 21

– Also trigger behavior. Internal sensory receptors, hormonal activity.
– Both are activated by: deviations from homeostasis, seasonal/reproductive cycles, maturation

– Internal stimuli modulates the IRM
- SS -> IRM -> FAP

Question 22

Reaction to stimulus requires

Answer 22

Sensory perceptions/sensation, command for action, and motor response

Question 23

What is the detection/response system required to respond to a stimulus

Answer 23

– Nervous system (endocrine system can chime in too, but more slowly - can change responsiveness of nervous system on short-term basis)

Question 24

What is the basic nervous system cell

Answer 24

Neuron
- Dendrites: receive signals, one neuron can have many dendrites
– Cell body: contains the nucleus;controls basic cell functions
– Axon: conduct signals away, only one axon per neuron. Can branch but there is only one

Question 25

What is a nervous signal

Answer 25

– Action potential: electrical, all or none signal
– – At rest, neuron membranes are negatively charged on inside; positively charged on outside
– – Neurons are essentially only batteries; separation of charges allows for the ability to do electrical work
– – Charges are attracted to each other; generally are separated, but work can be generated when they are brought together

Question 26

What is the difference in charge (membrane potential) between neuron membranes based on

Answer 26

– Buildup of an NA+ on outside, K+ on inside
– – Set up by the sodium/potassium pump
– –– Continuously running. Pump sodium out, potassium in, which sets initial conditions
– – Potassium keeps leaking out down its concentration gradients. Occurs through “leak channels”. Large negative proteins build up along inside of membrane and try to follow the potassium ions, but can’t escape

– Sodium on outside attracted to inside by negative proteins and by concentration gradient
– – But sodium ions can’t leak as easily as potassium, build up along outside of membrane

When neuron is stimulated, special gates will open to allow in sodium

Question 27

Resting membrane potential

Answer 27

-70mV (Equilibrium point between all forces)

Question 28

Three types of potential charges

Answer 28

– Depolarization: inside becomes more positive. Sodium rushes in when gated channels open, which is caused by stimulus
– Repolarization: Inside returns to resting potential after depolarization. Potassium rushes out through gated channels to restore negative charges around narrow zone inside of membrane
– Hyperpolarization: membrane potential drops below resting. Excess potassium rushes outs: inside of membrane becomes briefly more negative.

All these happen every time there is an action potential

Question 29

Action potentials (APs)

Answer 29

– All or nothing waves of the polarization that travel from trigger zone to axon tip. Returns to normal after wave has passed as it travels down next time. Initiation must occur in trigger zone – sodium gates open, cause positive feedback where more sodium gates then open, creating the wave of depolarization. Potassium gates immediately open and slam shut afterwords to allow membrane state to return to normal.

Threshold potential, refractory zone

Question 30

Nerve conduction is saltatory

Answer 30

– Myelin sheath: insulates axons. Lipid that wraps around and lets action potential skip entire parts of the axon – this is called saltatory conduction, speeds rate of conduction
– Found throughout the nervous system, peripheral nervous system/white matter of brain are also myelinated
– Takes time to develop – in people, it can take several years after birth to develop

Question 31

Types of neurons by conduction

Answer 31

– Sensory: receive and transduce (Turn into action potentials/turn stimuli into action potential language) stimuli
– Motor: cause effector tissues/organs to respond
– Association neurons: relay action potentials between neurons. Form neural networks – specific neuronal connections that control specific behaviors.

––all these connect together in different ways to form neural circuits. Certain neural circuits can control specific actions.

Question 32

Simplest neural network

Answer 32

– Reflex arcs
– Example: and sex responding to sound. Direct circuit from ear to muscles that controls flight. Fixed action pattern – here predator, flyway from sound. Here mate - fly towards sound.
– Brain doesn’t need to process

Question 33

Diverging circuits

Answer 33

Signal originating with single or limited number of neurons connected with multiple neurons at different layers to amplify signal (or vice versa) the deeper you go into network. (Ex - Retinas. Cones and rods converge to fewer and fewer neurons.)

Question 34

Reverberating circuits

Answer 34

Last one feeds back on first one to continue behavior until off switch is hit. Do not need ongoing presence of original stimulus.
– Example: when sea slug Tritonia encounters starfish. Neurons stimulated by pressure of starfish and sets off circuit that causes the slug to reflexively writhe/twist back-and-forth to move away. If it touches land or somewhere else, it is turned off.

– Tritonia slug escape response is controlled by the central pattern generator (reverberating circuit). Example: why we can still breathe while sleeping without thinking about it.

Question 35

Synapses

Answer 35

– junctions between neurons
– One-way transmission from presynaptic cell to postsynaptic cell
– Most are chemical.
– – Neurons don’t pass action potentials directly to one another.
– – 1. AP triggers calcium influx at the synapse
– – 2. Neurotransmitter released from presynaptic cell.
– – 3. NT crosses the synaptic cleft
– – 4. NT binds with receptors on postsynaptic cell
– – 5. Causes a change in membrane potential, either excitatory – depolarize – or inhibitory – hyperpolarize

Question 36

Neurotransmitter examples

Answer 36

Acetylcholine, serotonin (distress), dopamine (euphoric), GABA (occurs at inhibitory synapses - alcohol inhibits it)

Question 37

Release of neurotransmitter is by

Answer 37

Exocytosis

Question 38

What happens to the neurotransmitter after transmission

Answer 38

– Can be reabsorbed/reused by a presynaptic cell, can be degraded by an enzyme, diffuse away

Question 39

Each synapse is either excitatory (depolarizes the post synaptic cell) Or inhibitory (Hyperpolarizes the postsynaptic cell)

Answer 39

– Cannot do both. Needs balance of inhibition and excitation at all times. Stimulus to presynaptic cell fires one action potential, causes postsynaptic cell to depolarize, but is not strong enough. Must get up this threshold to fire (excitatory). Stimulus causes postsynaptic cell to hyperpolarize a little bit, goes back to resting (inhibitory)

Question 40

If APs are all-or-none, how are stimuli of different intensities distinguished?

Answer 40

Summation

• neurons fire APs (action potentials) at greater rate (temporal summation) (ex: hand in lukewarm water, presumptive cells fire at a selected rate. Will fire more rapidly at warmer temps.)
• more neurons are stimulated to fire (spatial summation)
• summary: for a whole neural circuit to respond to stimulus, stimulus must be strong enough to make neurons fire rapidly or make multiple neurons fire.

Question 41

Synaptic integration

Answer 41

Determines whether animals detect and respond to stimuli. Whether an AP occurs in the postsynaptic cell depends on sum of all excitatory and inhibitory inputs.

Question 42

Example of temporal summation

Answer 42

That detection by moths
Moth has reflex arc between hearing apparatus and flight muscles that control flight direction.
Sensory neurons in moths ear are constantly firing action potential, same as sensory neurons in our ears/skin that are firing at baseline rate, but certain stimuli increases the firing rate/cause more to fire.
Mark has a one and a two receptors – A1 heard quiet bat clicks, increases firing click, and goes back to baseline. More rapid bat cause more rapid firing. Causes a temporal summation that connects to motor neuron and causes temporal summation. Postsynaptic cell activates rest of reflex arc at high-intensity stimulus.
When A1 and A2 are both firing rapidly at the same time, both temporal and spatial summation occurs – one activates temporal, one activates spatial. Both postsynaptic cells fire at rapid rate. Causes a different response and moth.

Summary: A1 receptor fires more rapidly and response to louder bat clicks. Does not respond to steady sounds, causes moth to turn away from source. A2 receptor fires more rapidly only if clicks become very loud. Causes moth to fly erratically. Example of summation being required for response.

Question 43

Differences in behavior begin with differences in

Answer 43

Selective detection of stimuli (By the peripheral nervous system)
– Stimulus filtering: Ability to selectively receive and processes stimuli
– – Peripheral stimulus filtering: selective detection of stimuli by the peripheral nervous system
– –– More receptors dedicated to important stimuli. Receptors more sensitive to important stimuli a.k.a. tuning. Act as adaptation to environment. Density of certain sensory receptors adapted to animals ecology

Question 44

How can you explain why animals do what they do at a causation level

Answer 44

By explaining the nervous systems, what stimuli they respond to and are capable of firing action potentials from, and in turn finding out what types of muscle responses are possible

Question 45

Central stimulus filtering

Answer 45

Selective attention to stimuli. Some stimuli command more attention than others. Occurs at two levels, what gets in and what gets selectively processed
– Cocktail party effect: can pay attention to one thing/sound and tune out other sounds. Can still pick up something else important to you if it occurs.
– Preferential attention to supernormal stimuli: an example would be brood parasitism, host bird will preferentially feed the larger parasite chick because of its size or brighter mouth color

Question 46

What does it mean when the brain has more gray matter for processing stimuli from certain areas of the body

Answer 46

It represents a proportionate amount of brain dedicated to that

Question 47

What regulates the timing of behavior and how does the nervous system prioritize behaviors

Answer 47

– Command centers: clusters of neurons that control other neurons. Either located within CNS (central nervous system) or ganglia. ganglia: mostly found in invertebrates, are clusters outside of the central nervous system

Question 48

What to command centers to?

Answer 48

Inhibit inappropriate behavior. Allow appropriate behavior to proceed. Control duration of behavior until homeostatic setpoint is restored/physiological needs fulfilled. In humans: hypothalamus, prefrontal cortex, medulla oblongata are all command centers.

Question 49

Praying mantis nervous system

Answer 49

– Only three important command centers for prioritizing behavior: proto-cerebral ganglion (which is inhibitory), subesophageal ganglion (excitatory), Abdominal ganglia (Innervate each segment – one for each segment)
– Arranged like gas pedal/brake pedal. Constant stream of excitation coming from esophageal ganglion to abdominal ganglion. Protocerebral ganglion inhibits inappropriate abdominal ganglia. Is connection severed, mantis performs multiple behaviors simultaneously. If whole head severed, all behaviors cease except mating. Adaptive!

Question 50

What allows animals to time behavior appropriately giving competing commands all at once

Answer 50

– At proximate level, controlled by command centers. On a longer timescale, controlled by biological rhythms – repeated cycles of behavior. Behavior is timed with favorable conditions. And/or it may be synchronized to group behavior.

Question 51

Types of biological rhythms

Answer 51

Circadian, Circannual, lunar, tidal

Question 52

Circadian rhythms

Answer 52

Animals active at different times of day. Nocturnal, diurnal, crepuscular.
– Controlled by endogenous clock, which is the physiological mechanism. Doesn’t require external cues to run.
– – Example: animals under constant light/darkness, will continue to exhibit predictable cycles, called free running rhythms. Not quite 24 hours long, will eventually drift away from the day-night cycle

Question 53

Zeitgeber

Answer 53

Environmental cues that entrain the timing of biological rhythms
– Light/darkness is the zeitgeber for circadian rhythms
– Example: honeybee entrainment – honeybees flown from NY to CA. Found that it took a few days for the bees to adjust – based on foraging times. Time of foraging initially at old time before slowly adjusting to the new time zone

Question 54

Where is the endogenous clock located

Answer 54

Suprachiasmatic nucleus (SCN) of the hypothalamus.
– Cyclical gene activity (PER) In the SCN.
– SCN stimulates other brain regions via the release of PK2 (prolineticin), that puts brain into sleep mode.
– Cycle: PER protein peaks, some degraded by tau protein, some feeds back to inhibit PER transcription
– In fruit flies, there is the same PER gene that works in the same way. Mutant flies with messed up PER genes can have longer active period than normal or mutants Can have arrhythmic sleep/wake cycle, or be a short-period mutant.

Question 55

Action potentials (APs)

Answer 55

– All or nothing waves of the polarization that travel from trigger zone to axon tip. Returns to normal after wave has passed as it travels down next time. Initiation must occur in trigger zone – sodium gates open, cause positive feedback where more sodium gates then open, creating the wave of depolarization. Potassium gates immediately open and slam shut afterwords to allow membrane state to return to normal.

Threshold potential, refractory zone

Question 56

How does the SCN communicate with brain regions that directly control wakefulness/sleepiness

Answer 56

– Cyclical PER activity causes cyclical release of PK2 (prokineticin 2) from SCN
– PK2 activates other brain regions
– The SCN receives input from retinas allowing environmental light to serve as zeitgeber

Question 57

Zeitgebers for circannual rhythms

Answer 57

Photoperiod – Most important. Temperature, rainfall, social environment (zeitgebers trigger hormone changes; hormones then directly regulate behavior)

Question 58

Example of species whose circannual physiology is connected to photoperiod and who is also sensitive to food

Answer 58

Red crossbill. Can start breeding early in spring. In male, changing photoperiod triggers testes to change size as days get longer in spring. Maximally large in summer. At end of breeding season, testes are reabsorbed. Repeats every breeding season
– day length increases -> testes grow -> promotes sperm production, suppresses immune system, stimulates aggressive behavior -> testosterone increases -> testosterone directly regulates reproduction
– Crossbill breeding also responsive to food availability. Geared to take advantage of unusual increases in food supply. Males will begin breeding earlier in spring if food is abundant

Question 59

Example of species whose circannual physiology is connected to social cues

Answer 59

Infanticidal behavior by male house micr organized by time since last copulation: infanticide rate high from immediately after mating until three weeks after. Declines after three weeks. Increases again after seven weeks. What’s the ultimate explanation? Offspring grown and dispersed at that point.
– Here’s the approximate explanation: sensitive to number of day night cycles. Scientists put some males on shorter day night cycles, lengthened the cycles of other males to prove this

Question 60

Sometimes the relationship can be complicated between hormone environmental cue and behavior

Answer 60

Garter snakes reveal complicated relationship between zeitgebers and hormones
– Warmspring temperatures wake them up. Start cording and mating but testosterone isn’t high during spring. Temperature and NOT photoperiod wakes them up (cold blooded, only able to be active up warmer temps, plus have underground hibernacula)
- is testosterone therefore unimportant? No. If you remove testes, the courtship behavior will decline. Shows testosterone is important, but not as important as in birds and some other animals for triggering the behavior. Don’t need a surge of it to start mating in spring.

Question 61

spatial organization of behavior

Answer 61

Orientation: the way in which an animal positions itself in relation to external cues
Navigation: movement from an origin to a specific destination through knowledge of direction and position
Homing: returning to a specific site following a displacement, requires navigation.

Question 62

Types of orienting movements

Answer 62

Kinesis: nondirectional response to a change in stimulus intensity (Example – insect crawling faster until a suitable place is reached, but no specific direction)

Taxis: directional response to a stimulus source

Question 63

Types of taxis

Answer 63

Phototaxis - moving towards or away from light
Chemotaxis – Example: avoiding another animals urine
Geotaxis – example: cicadas crawling up when the time to emerge is reached is an example of negative geotaxis

Question 64

How do animals navigate non-reflexively

Answer 64

Landmarks, magnetic fields, olfaction, celestial cues like sun and stars (biological clock required for celestial navigation)

Question 65

How do you test compass hypothesis

Answer 65

Example: Monarch butterflies. Use circular statistics, which is where number of animals that orients on certain compass direction are calculated whether the orientation is significantly different from an expected average. Butterflies on different light cycle orient differently from the ones on the normal cycle

Question 66

How do you test magnetic compass hypothesis

Answer 66

Artificial magnetic fields. Example: put see turtles and temporary plastic poles and exposed them to artificial magnetic field – one gave them perception that they were further north than they really were. Made them orients more south than the control group

Question 67

Navigation to foraging sites by honeybees

Answer 67

Flower patch direction: landmarks, sun compass if landmarks are unfamiliar
Flower patch distance: may use energy expenditure, or movement of landmarks across eyes
The dance communicates direction and distance: round dance if food is within 50 m, waggle dance if greater than 50 m
– Angle of waggle portion from vertical equals angle of food from the sun. Duration of waggle portion equal food distance