Flashcards in Lecture 7 Deck (70)
How do whales communicate?
very specific song patterns
If blue whales are found in pairs they may be several...?
Does sound travel faster in water or air?
Sound travels up to 5 times faster in water than in air.
What is the breadth of blue whale calls?
Whales can produce calls as low as 14 Hz and as loud as 180 dB
Due to noise pollution what has happened to the hearing ability of blue whales?
they can only hear 100 miles away as oppose to 1000 miles away in 1940
Male songs have dropped in pitch by 30% since 1960s.
Right whales now communication at frequencies ______________ higher than they did a century ago.
2/3 of an octave
What do blue whales do when they find food?
tend to emit mid-frequency calls and communicate with conspecifics in the area
What study did Goldbogen conduct?
Performed a series of studies on the disruptive effect of mid-frequency sonar on blue whales
what sound does military sonar emit?
emits sounds between 1-10 KHz
What has military sonar frequencies been linked to?
mass strandings and large scale mortality, especially in beaked whales
The mid frequencies are ________ than the most sensitive auditory perceptive range in most toothed whales.
the mid frequencies are _______ that the long distance calling frequencies.
What kind of effect did military sonar have on whales that surface fed?
they showed little to no change in behavior pattern
What kind of effect did military sonar have on whales that deep dive fed?
suddenly terminated feeding
switched to mid water dive
increased swimming speed
swan away from sonar emission
what gender produces loud songs and why?
only male blue whales sing loud songs to find mates
Two types of hearing:
how do particle detectors work?
long thin organs that move when barraged by many particles
--only work in near field
Give an example of an animal with a particle detector
--courtship dance of male flies that females can detect and monitor near filed signals with an arista
What is an example of particle detector in male mosquitos?
Plumose antennae are used to detect the species specific wing beat of females.
What's an example of a particle detector in roaches and crickets?
Very fine hairs at the tips of their abdomens
• Variations in the lengths of these hairs is correlated with the particular near field sound frequencies to which each hair is sensitive
how do particle detectors provide mechanical advantage to an animal?
long hairs and antennae that attach to the cuticle of the animal.
--small force distributed over the axis of hair is sent to sensory cells as small displacement but one of great force.
What are some other advantages of particle detectors
very weak sound field can be detected by these types of receivers
mosquito antenna are one of the most sensitive auditory receptors among anthropods.
What are some cons of particle detectors?
signal amplitude and direction are confounded
dipolar near fields dont produce particle movements whose axis points at the source
What are the characteristics of particle detectors?
• lower frequencies
• Dynamic ranges and temporal tracking ...
• slowly varying waveforms well
• Provide relatively undistorted signals to sensory cells • Inherently directional
• Use is limited to near fields
describe a pressure detector?
Tympanum couples sound to the medium, relies on pressure differences on each side of membrane.
What happens if there's unequal pressure?
the membrane is bent away from the side of higher pressure. This bending can be coupled to sensor cells to produce neural impulses
Pressure detectors consists of...?
consists of a tympanum stretched over a closed cavity
how do pressure detectors work?
• As air pressure changes on one side of the tympanum it will bulge and bend to accommodate these changes causing vibrations along the membrane
• These vibrations can then be coded and transmitted to sensory cells
What is the equation for pressure detectors?
The force (F) on a tympanum is equal to the product of sound pressure (P) and membrane area (A); F=PA