This site is 100% ad supported. Please add an exception to adblock for this site.

sinal honesty, communication channels, Evolution of displays

Terms

undefined, object
copy deck
What is INFORMATION THEORY APPROACH?
-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?
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?)
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?
messages

animals use enrichment devices
What are enrichment devices?
-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?
-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)
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?
-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)
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
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
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)?
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
-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?
-easily detected by illegitimate receivers

-requires a direct un-obscured line of signal btw sender and receiver
Describe AUDITORY Channel
-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?
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
TRUE/FALSE
HARD to locate sounds with low to moderate frequency without abrupt transmissions. (Alarm.warning calls)
TRUE
TRUE/FALSE
Senders can modify sound quality to minimize detection by particular predators
T
TRUE/FALSE
Signal propagation depends on env. characters, background noise, etc
T
TRUE/FALSE
Complexity of signal conflicts with range characteristics (high frequency are short-range but lots of info)
T
TRUE/FALSE
Acoustic signals can be expensive to produce
T
True/False
EASY to locate soounds with moderate to high frequency, with abrupt transition (typical bird song)
TRUE
Describe Olfactory Channel
-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?
-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)
-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
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
True/False
Communication is Reducation of uncertainty
T
What are the pre-existing behavior or struture of DISPLAYS?
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?
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?
transfer of communication from one display to another
or
a communication function can be "divided" among different displays

Deck Info

48

permalink