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Flashcards in Lecture 9 Deck (27)

Define anthropomorphism

assigning human emotions and feeling to animals that don't run with our spectrum of visual and emotional cues.


What are some species in the animal kingdom that suffer limited predatory threat?



Predation is almost ________



among group living species, some individuals may produce what?

vocalizations or other warning sounds to alert the conspecifics in the area to a potential threat (produce a predictable change in behavior among group)


Describe reciprocal altruism?

consistent groupings
individual recognition
Some form of cost/benefit assessment


What are some functional hypotheses of alarm calling?

individual selection
kin selection


Describe individual selection

Manipulate action of conspecifics
--facilitate group formation and cohesion
--silence group members to decrease predator detection
--reduce chance of future attack


Benefits to individual selection hypothesis?

Alarm signals represent a form of mate investment
--invite predator pursuit
--deter predator pursuit
--confuse predator orientation when alone


Describe the kin selection hypthesis?

warn kin of varying degrees of relatedness
to defend offspring


what's the difference between vocalizations used to attract mates and alarm calls?

vocalizations for mates are easy to locate and are low frequency and have clear start and stop points to help with localization.
--alarm calls need to be difficult to locate


What are some factors that influence the detectability of alarm calls?

Amplitude of the signal at the sound source
 2. Attenuation characteristics of the environment
 3. Signal-to-noise ratio at the perceiver
 4. Discrimination ability of the perceiver against the background noise
 5. Auditory sensitivity of the perceiver


why should production capabilities of the sender and perception capabilities of the receivers matter?

Conspecifics must be able to avoid predation
 Predators must be confused or challenged by the same signal


__________ noise is easier to localize than __________ noise

broadband, narrowband (pure tones are difficult to localize)


what kinds of calls are more readily localized?

frequency modulated calls (like sage grouse stridulation)


how does environment impose its own effects on signal structure:

most alarm calls under lab conditions (in the absence of broadband noise) appear to be frequency-modulated


the composition of similar species (sympatric species) in a given area should what?

should create a situation where alarm calls overlap; calls should be understood across species boundaries


why should alarm calls show distinct overlap

Since environmental pressures are similar and sound producing equipment is similar;


What did marler observe about alarm calls.

Single, brief duration “seeet” call  Low amplitude
 High frequency (narrowband)
 Gradual onset


marler found that alarm calls in birds causes what?

others to seek cover. Alarm calls in different bird species have similar structure:


unlike alarm calls, mobbing calls are made of what?

Repeated series of loud “chuck” calls
 Wide range of frequencies (broadband)
 Sudden sharp onset and offset


when does mobbing behavior occur?

when predators perch in an area and the threatened species work together to drive away the intruder


what did molar suggest about alarm calls?

shaped by strong selection pressures. Alarm calls reveal a clear trade-off between detectability and localizability


What kinds of sounds are hard to localize?

narrow band of frequencies and gradual onsets and offsets are hard to localize


What are the 5 points of Marler's hypothesis?

1. Small animals are better at detecting high frequencies than larger animals (e.g., predators)
 2. Sounds with gradual onsets and offsets are hard to localize
 3. Narrowband sounds are harder to localize than broadband
 4. High frequencies are linked to fear rather than attack
 5. Mobbing calls are repeated in a loud voice to attract others


________ _______ are linked to fear rather than attack.

high frequencies


What is the best course of action for alarm calling?

Use brief, high-frequency sounds without sharp onsets to avoid localization  Use longer, more intense, broadband sounds to attract attention


what does alarm call detection depend on?

1. Amplitude of signal at the source
 2. Attenuation characteristics of environment
 3. Signal-to-noise ratio at the receiver
 4. Sensitivity and discrimination ability of the receiver