Week 10 - Sensory biology

Question 1

What does this mean Sensory systems are ecologically optimized

Answer 1

Shaped by each species’ needs.

Question 2

What is perception?

Answer 2

A brain-constructed reality based on sensory input. Not a direct image of the word

Question 3

What is the difference between passive and active sensing?

Answer 3

Passive sensing= sunlight (environmental energy)
Active sensing = self-generated energy

Question 4

What are the costs of sending (communication)?

Answer 4

• predation
• parasitism
• energy
• time budget

Question 5

What are the costs of receiving (communication)?

Answer 5

• predation
• parasitism
• energy
• time budget

Question 6

When does communication occur ?

Answer 6

When benefits > costs

Question 7

How do communication signals affect behaviour ?

Answer 7

Trigger, stop or modify behaviour

Question 8

What components does animal communication require?

Answer 8

Sender and a receiver

Question 9

What are the 3 sources of information?

Answer 9

1. Internal state (hormones)
2. Environment
3. Other individuals (social signals)

Question 10

What types of meaning can communication signals have?

Answer 10

Announce species, age, sex, individual
Broadcast location/ sexual status
Environmental cues (alarm signals)
Private vs public info

Question 11

What does monochromatic mean and give an example of an organism with this?

Answer 11

One colour - cephalopods (green)

Question 12

What is unpolarized light?

Answer 12

Contains waves vibrating in all directions

Question 13

What does a polarizer do?

Answer 13

Filters out all but 1 vibrating direction = linearly polarized light

Question 14

What is an example of unpolarized light ?

Answer 14

Sun/moon light

Question 15

At which wave length is the scatter of light stronger?

Answer 15

Shorter - blue sky, red sunset

Question 16

What causes night-time polarization patterns and what disrupts them?

Answer 16

The moon - light pollution

Question 17

What is bioacoustics?

Answer 17

It is the study of biological sounds, mainly concerned with:
Sound [production] in animals
Sound [propagation] in water
Sound [reception] capabilities

Question 18

What does sound require?

Answer 18

A medium ( air, water ect )

Question 19

Which medium do transverse waves travel through?

Answer 19

Solid

Question 20

Which medium do longitudinal waves travel through ?

Answer 20

Air and water

Question 21

Which two speeds are involved in sound?

Answer 21

1. Propagation speed of wave (speed of sound)
2. Speed of oscillating particle (particle velocity)

Question 22

How is loudness measured?

Answer 22

The change in oscillation pressure

Question 23

What kind of oscillation produces louder sound ?

Answer 23

Higher

Question 24

What is the decibel scale and who’s idea was it?

Answer 24

It compresses values into a practical range (0–140 dB) and reflects how our ears perceive loudness (non-linear).
Bell’s idea

Question 25

What is the threshold sound pressure?

Answer 25

20μPa=0.00002Pa

Question 26

What is the calculation for dB ?

Answer 26

20 x log10 (Pressure measured / threshold sound pressure)

Question 27

What is the human hearing threshold?

Answer 27

0 dB SPL

Question 28

What change in dB can we perceive as being different ?

Answer 28

1dB

Question 29

How many dBs does a sound get half or twice as sound ?

Answer 29

+ OR - 6

Question 30

How can you calculate wavelength?

Answer 30

Speed of sound / Frequency

Question 31

What is an oscillogram ?

Answer 31

Plots the sound pressure as measured by the microphone as a function of time

Question 32

What does a power spectrum show?

Answer 32

The power of sound (db) as a function of frequency

Question 33

Where are mechanical sounds derived from?

Answer 33

Movements (wings and legs) Thermoregulation (shivering) Food processing (tongue clicking and grinding) Body- on- body contact Body-on-environment contact

Question 34

What is insect stridulation?

Answer 34

Producing sound by rubbing together 2 body parts e.g. Hindleg scraper & wing file

Question 35

How do Circadas produce their clicking sound?

Answer 35

Contacting of internal timbal muscles produces clicking sound - Air filled cavities in abdomen amplify the sound

Question 36

Which fish use swim bladders to produce sounds?

Answer 36

Grunts, drums and croackers

Question 37

Which fish use stridulation by grinding their teeth?

Answer 37

Sea horses

Question 38

Which fish release air from their anus ?

Answer 38

Herring

Question 39

How are substrate vibrations used for communication?

Answer 39

Small vibrations of plant made audible by laser vibrometry

Question 40

Where are respiratory sounds produced in mammals ?

Answer 40

Larynx - generates a sound rich in overtones

Question 41

Which size of animal produces lower pitches give an example

Answer 41

Large - elephants

Question 42

How does vocal cord length correlate with pitch?

Answer 42

Longer cord = lower pitch

Question 43

How do birds vocal production differ to humans?

Answer 43

Birds have a syrinx with 2 separate valves meaning they have independent control of both sides

Question 44

What is beam forming ?

Answer 44

Sending sound in certain directions

Question 45

How does a beam of sound from a mouth form in air?

Answer 45

The geometry of the mouth opening (wide, narrow, round, pointed) affects how sound is projected into space. Airborne sound is reflected by tissue

Question 46

How is sound produced in bottlenose dolphins?

Answer 46

Larynx is missing so sound is produced with phonic lips in the nasal airway

Question 47

What does acoustic impedance mean?

Answer 47

Measures how much resistance a medium gives to sound passing through it. The closer the impedances of two media the better sound passes form one medium to the other

Question 48

What does a high impedance difference mean in water and air

Answer 48

Strong reflection at boundary (e.g. air–water interface).

Question 49

How do you work out impedance ?

Answer 49

Density x Speed of sound

Question 50

Does sound travel faster in water or air ?

Answer 50

Water