General Flashcards
Hearing organs are specialised structures that serve the following primary physical functions:
The coupling of sound to the organism
The conversion of sound into mechanical energy
The conversion into useful nerve signals
Physical dimensions of sound
Frequency range Frequency resolution Temporal resolution Amplitude range Amplitude resolution
Human amplitude threshold
1000 Hz (1dB)
Minimal energy detectable for a human at threshold
4zJ
Tool to estimate the frequency composition of a waveform
Fast Fourier Transform (FFT)
Sound graphs:
Amplitude over time
Frequency over time
Frequency and relative amplitude / overall frequency composition
Amp - oscillogram
Freq - sonogram
Freq and amp - power spectrum
Proximal adaptations for hearing
How
Directionality
High sensitivity
Frequency selectivity
Ultimate adaptations for hearing
Why
Mate detection
Predator detection
Prey detection
Transmission - object size to wavelength ratio
1:10
Diffraction - object larger than …… of the wavelength
1/10
Water depth where sound transmits well
600 - 800 m
Resolutions and ranges humans can detect: Frequency range Dynamic range Frequency resolution Temporal resolution Amplitude resolution Angular resolution
Frequency range = 20 Hz - 20 kHz Dynamic range = 0 dB - 140 dB Frequency resolution = 1% Temporal resolution = 1 us Amplitude resolution = 1 dB Angular resolution = 1 degree
Two types of hearing organs and what they respond to
Pressure receivers - pressure
Particle velocity receivers - particle velocity
Number of mechanosensory cells at pedicel of chironomid fly antennae
16,000
Directional hearing acoustic cues
Interaural time difference
Interaural amplitude difference
Spectral information (frequency content)
Types of systems for hearing directional information
Independent pressure receivers
Pressure difference receivers
Mechanically coupled pressure receptors
Ormia ochracea mechanical ITD
Delay measured by microphone
50 us
1.4 us
Frequencies associated with coupled tympanal membrane modes
Mode 1 - low frequency (4 kHz)
Mode 2 - intermediate
Mode 3 - high
Arachnoscelis / Ultrasonus frequency of communication
153 kHz
Who discovered Ampullae of Lorenzini and when?
Stefano Lorenzini (1678)
% overall energy some flowers invest into nectar production
37%
Charge density unit
Volts per meter
What do we need to ask when looking at a sense?
Cues, physical quantities Behavioural evidence Detection, perception Thresholds Sensory substrate Adequate stimulus, information
Chemical formula of magnetite
Fe3O4
What is the significance of H vector?
Points to magnetic N
What is angle D?
Declination angle
Between geographic and magnetic north
What is angle I?
Inclination angle
Angle of the horizontal plane
Field intensities information
Ambient field
Local variations
Behavioural thresholds
Ambient field = 30,000 - 60,000 nT
Local variations = 1,000 nT
Behavioural thresholds = 25-50 nT
The successive phases of long-distance navigation
Long-distance phase - celestial, magnetic, landmarks
Homing phase - compasses, landmarks, olfaction, soundscapes
Pinpointing the goal phase - cues
Speed of light
300 x 10^6 ms^-1
Irradiance levels in different light levels and types Photopic Sunlight Sunrise / set Mesopic Twilight Full moon Scotopic Starlight
Sunlight = 10^20 Sunrise / set = 10^18 Twilight = 10^16 Full moon = 10^14 Starlight = 10^12
Threshold irradiance for human vision
10^10 Ph m^-2 s ^-1
What can happen when a molecule absorbs a photon?
Vibrate
Electrons excited and jump to higher energy state
Ionized
What can excited molecules do?
Fluoresce / phosphoresce
Change shape
React with another molecule
Break apart
Spectroscopy measurements
Transmission
Absorptance (P)
Absorbance (A)
% space in rod outer segment occupied by rhodopsin
50%
Chromophore molecule name
Rhodopsins
Porphyropsins
Retina
3,4-dehydroretinal
How long does the cis trans isomerisation of retinal take
500 femtoseconds
Rod maximum absorbance and absorption range
498 nm
350 - 580 nm
Blue pigment maximum absorbance
420 nm
Green pigment maximum absorbance
534 nm
Red pigment maximum absorbance
564 nm
Visible light wavelength
400 - 700 nm
Types of heat sensor
Convective
Radiant
Forest fire temperature and wavelength
425 - 1,000 degreesC
2 - 3 um
How many mya was the Cambrian explosion?
530 mya
Duration of the Cambrian explosion
5 my
Number of facets in anomalocaris
15,000
When was Haikouichthys around?
500 - 550 mya
Stages of the evolution of the eye
Detect light
Screening pigment
Membrane stacking
Lens system / focusing optics
What is non-directional photoreception used for?
Monitoring light intensity
Depth control
Entrainment for a circadian clock
Shadow response
Characteristics of non-directional photoreception
Typically slow response
Large dynamic change
No adaptation
How many degrees does each photoreceptor in the eye of a nautilus sample?
25 degrees
Where colour vision has evolved and how many times
Twice
Vertebrates
Ecdysozoa
Who won Nobel prize in 1920s about how animals see colour?
Karl von Frisch
Why is colour vision important to the ecology of animals?
Signals
Camouflage
Communication
3 mechanisms of colour vision
Changes to the opsin
Using a different chromophore
Filters
Vertebrate and invertebrate rhodopsin types
V - C-type (ciliary)
I - R-type (rhabdomeric)
Position chromophore attached to
296
Bond of chromophore to opsin
Covalently
Residue chromophore bonded to
Lysine
Order of signal transduction cascade - vertebrates
Chromophore Rhodopsin Transducin PDE cGMP cGMP gated channels closed Hyperpolarisation
Order of signal transduction cascade - invertebrates
Chromophore Opsin Gq trp channels opened Depolarisation
Full name for A2
3,4-dihydroretinal
Chromophores invertebrates use
A1 and A3
A1 sensitivity
630-640 nm
A2 sensitivity
Up to almost 770 nm
When did stomatopods split from other crustaceans?
280 - 300 mya
How many stomatopod species and superfamilies?
Over 500 species
9 superfamilies
3 parts of the stomatopod eye
Dorsal hemisphere
Ventral hemisphere
Mid band
Number of stomaptopod UV visual pigments
6
What is polarisation created by?
Scattering
Reflection
Polarisers
Stages in polarisation sensitivity
Molecular
Cellular
Neural / behaviour
Who studying Saharan ants and polarisation?
Rudiger Wehner
Degree of polarisation in light polluted vs rural
16% vs almost 50%
Crustacean angle of polarisation resolution
10-15 degrees
Stomatopod group that uses polarisation and structural colour
Haptosquillids
SWS bird cone sensitivity
Ultraviolet or violet
When maximally sensitive to UV = 360 nm
Who studied sexual dimorphism in bird UV reflectance?
Ben Sheldon
Why high contrast patterns as aposematism / what do they increase?
Saliency, memorability, consistency
Irradiance spectrum at 1500 m compared to surface
12 orders of magnitude less
Maximum transmission at 1500 m
460 nm
Maximum transmission for water vs fish (marine)
Water - 460 nm
Fish - 480 nm
Deep sea red sensitive visual pigment species
Changing chromophore from A1 to A2 can give opsin maximally sensitive to:
520 and 551 nm
588 and 669 nm
Methods of fiddler crab communication
Vibrations
Colour
Movement
Action-perception cycle
Sensory transduction Sensory processing Multi-sensory integration Sensorimotor tranformation Motor activity
Who asked how insects detect directional motion and when?
Hassenstein and Reichardt (1953, 1956)
Layers in insect brain that visual inputs pass through (in order)
Lamina
Medulla
Lobula
Which photoreceptive cells are an exception to the order visual inputs pass through in the insect brain? Why?
R7 and R8
Skip lamina
Where is optic flow processed and used in the insect brain?
Lobula plate