sinal honesty, communication channels, Evolution of displays
Terms
undefined, object
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- What is INFORMATION THEORY APPROACH?
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-communication and signaling is a reduction of uncertainty
-Any action by or charateristic of one organism which alters the probability pattern of behavior or other characters in another organism
-Sender --->receiver---->change in behavior - Why is information theory difficult to study?
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1)many animal signals are not detected easily by humans
2)it is frequently hard to ascertain what constitutes a "response" - How is information theory studied? (masuring what?)
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measuring the statistical association of putative signals and responses
X1 signal
X2 response
p(X1) probability of sender's act
p(X2) probability of receiver's act
info exchange occurred when:
p(X2), given X1(the signal) is NOT statitically equal to p(X2) in the ABSENCE of X1. - What is a BIT?
- the amount of infor needed to control two equally probable alternatives with 100% certainty (ON-OFF, YES-NO) 2 bits, control 4 alternatives, 3 bits, 8alternatives.
-
True/False
ALL animal signals are imperfect
Rates of info transmittion in bits/sec rather low (human speech avg 6-12bit/sec) - TRUE
- What is DISPLAYS?
- discrete signal patterns
- In most species, more displays or messages are possible? why?
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messages
animals use enrichment devices - What are enrichment devices?
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-change the intensity or duration
-composite signals(growling dog)
-syntax(not common) or Context -
TRUE/FALSE
Signals will NOT evolve unless the sender benfits (gains fitness) - TRUE
- What are the disadvantags of singals?
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-energetic cost of producing signal
-Illegitimate signalers or receivers
-propagation characteristics of the environment -
TRUE/FALSE
The value to sender depends on the RESPONSE of RECEIVER - TRUE
- What are 3 types of Sender/Receiver signaling relationships? (3)
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1.Helpful signaling (both benefit)
2.Deceiful(dishonesty) signaling(helps sender, hurts receiver)
3.Eavesdropping(helps receiver, hurts sender)-illegitimate receiver - What are the general examples of dishonest signals?
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-threat signals exchanged when individuals fight
-warning signals in predaor-prey interactions
-courtship signals -
TRUE/FALSE
Most signals where there is potential for conflict of interest between sender and receiver are subject to dishonesty. (majority of animal signals) - TRUE
- How to judge HONESTY of signal?(how much reliable info)
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judge "quality" of sender from signal INTENSITY
-Honest signal-HIGH info content
-Dishonest- no info content -
TRUE/FALSE
Theoretically all signals must have a cost - TRUE
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TRUE/FALSE
Signals MUST be costly to sender to be of value to reciever (receivers must require that a signal be costly as a test of sender's honesty) - true
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Describe "Handicap Principle"
(Zahavi)
examples? -
signalers demonstrate quality by their ability to survive with a handicap
Bright colors, long tails, antlers, bizaree structures usually worn by males
-females pick males with handicaps because these males obviously had other, compensatory qualities that enabled them to survive - What is a problem with "handicap principle?"
- offspring of females who pick handicapped mates will carry handicap genes and hence wil be less fit (PENALIZING the females who prefer handicaps)
- What did Maynard-Smith say about the handicap model?
- will work if handicaps have a higher fitness cost in a "low-quality" male than in a "high quality" male (signal must be an honest indicator of quality)
- What are 2 general types of signals (Maynard-Smith)?
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1.NOTICES (signal benefits both-no conflict of interest)
2.ADVERTISEMENTS(signal involved in a conflict of interest btw sender and receiver) - Describe VISUAL channel
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-well studied
-Modification of existing light (except bioluminescence)
-Instantaneous, high resolution transmission
-high rate of transmission(rapid modulation)
-complex composite signals, which can be sent simultaneously (facial expression)
-low energy cost, but can be expensive if modification of body parts is elaborate or muscle activity high (or bioluminescence used) - What are the problems with visual channel?
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-easily detected by illegitimate receivers
-requires a direct un-obscured line of signal btw sender and receiver - Describe AUDITORY Channel
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-well studied
-Production of sound
-Fast (esp in water)
-Rapid modulation possible
-can use highly variable frequencies and timing, can be highly specific
-NOT require direct line of sight
-less easy to locate than with vision, but many predators can localize sound. (directionality is highly dependent on sound quality -frequency) - What are 3 mechanims to localize sound?
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1."Sound Shadow"of head-works if wave length is less than head dimension
2.Phase changes between ears-head blocks the sound wave
3.Arrival time at different ears-very difficult to locate low frequency -
True/False
EASY to locate sounds with moderate to high frequency, with abrupt transition (typical bird song) - TRUE
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TRUE/FALSE
HARD to locate sounds with low to moderate frequency without abrupt transmissions. (Alarm.warning calls) - TRUE
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TRUE/FALSE
Senders can modify sound quality to minimize detection by particular predators - T
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TRUE/FALSE
Signal propagation depends on env. characters, background noise, etc - T
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TRUE/FALSE
Complexity of signal conflicts with range characteristics (high frequency are short-range but lots of info) - T
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TRUE/FALSE
Acoustic signals can be expensive to produce - T
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True/False
EASY to locate soounds with moderate to high frequency, with abrupt transition (typical bird song) - TRUE
- Describe Olfactory Channel
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-extremely important to most animals except birds
-effects may be subtle, delayed
-alarm, aggregation, individual or cology identity, trail-marking and oreintation, territorial markers, sex attractants, social control, status indication in group-living species
-primers(long-term responses or physiological changes) and releasers(short-term responses)
-messages linger(transmitted across time as well was across distance)
-can transmit through darkenss and around obstacles
-highly energy-efficient (tiny amout of chemical can linger for hours or diffuse impressive distance)
-may be extremely specific and hence hard for illegitimate receivers or senders to "break into" - What are the problems with olfactory channel?
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-transmission and range dependent on env.
-Water-borne phermones, dependent on currents since diffusion slow in water
-Signal complexity depends on having different chemicals for different messages(not always)
-chemical charactersitcis of pheromone greatly influence propagation and persistence. Must be complex enough to be specific. The bigger, slower, more expensive - What are the 3 key chemical/physiological aspects of pheromones? (persistence, range, fade time, directionlaity)
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-volatility (determined by chemical properties)
-Detection threshold (determined by sensitivity of olfactory system)
-Emission rate (physiology of sender) -
True/False
For longer range, Smaller moleculte is best (high sensitivity, high emission rate, high volatility) - T
- Communication in any modality is usually a compromise between_____ and_____
- costs and benefits
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LIGHT
1.speed
2.modulation
3.complexity
4.range
5.energy cost
6.risk -
1.speed-instant
2.modulation-fast
3.complexity-high
4.range-line of sight
5.energy cost-usually low
6.risk-high -
SOUND
1.speed
2.modulation
3.complexity
4.range
5.energy cost
6.risk -
1.speed-fast
2.modulation-fast
3.complexity-high
4.range-variable
5.energy cost-low to high
6.risk-moderate -
OLFACTION
1.speed
2.modulation
3.complexity
4.range
5.energy cost
6.risk -
1.speed-slow
2.modulation-slow
3.complexity-low
4.range-variable
5.energy cost-moderate
6.risk-low -
TACTILE
1.speed
2.modulation
3.complexity
4.range
5.energy cost
6.risk -
1.speed-moderate
2.modulation-moderate
3.complexity-moderate
4.range-very short
5.energy cost-low
6.risk-low -
ELECTRORECEPTION
1.speed
2.modulation
3.complexity
4.range
5.energy cost
6.risk -
1.speed-fast
2.modulation-fast
3.complexity-moderate
4.range-low
5.energy cost-moderate
6.risk-low -
True/False
Displays evolved from other behaviors that were not directly related to communication but could be used to predict behavior of the "sender". - T
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True/False
Communication is Reducation of uncertainty - T
- What are the pre-existing behavior or struture of DISPLAYS?
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Locomotion
Grooming or comfort movements
Feeding or food handling
Breathing, respiration, temperature control
defecation, urination, sweating etc
Conflict behvior, intention movements, redirected behavior
another display - What is ritualization?
- Evolutionary enhancement of communication function (often at expense of original function)
- How to study evolution of a display that is highly ritualized?
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use comparative studies of related species
-can "trace" evolution of a display by observing different stages of the display in different species - What is Secondary ritualization?
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transfer of communication from one display to another
or
a communication function can be "divided" among different displays