Sensory ecology Flashcards
Tetrachromats
extra cone in eye - UV sensitive
Fish and birds
Tapetum
Guanine - reflects light bak through retina to be absorbed 2nd time
Apposition
all light from one facet goes to same photoreceptor cells
Superposition
Light from diff angels goes to diff photoreceptors
More sensitive
Producing colour
Pigments
Structural colour - constructive interference creates iridescent/metallic look - beetles
Deep sea adaptations
Bioluminescence
eyes adapted to low light
Barrel eye - eyes facing up with large lenses
Spookfish - 2 eyes facing up and 2 down - can rotate to look forward
Lures
Dragonfish use photophores under eyes as search light - emits red light - invisible to deep sea animals
Tend to be red or black in colour - camo
swim bladder lost due to high pressure
Passive senses
Collect info using available energy (sunlight, ambient sounds)
Active senses
probe the environment with self generated energy - analyse how the environment modifies the outgoing energy
Communication
Cost of sending and recieving:
Predation
Parasitism
Energy
Time
Triggers, stops or modifies behavour
Types of communication
Announce species/sex/age/individual
Broadcast presence and location
Indicate current status
Change status of social unit
Near field interactions
Why are sounds useful
Work in dark
Work out of sight
Omnidirectional
Localisation
Adapted to needs - range of distance - can be switched off - carry diff meanings
Mechanical sounds
Movements
thermoregulation
Food processing
Mutual contact between body parts/ body and environment
Respiratory sounds
Non vocal - breathing
Vocal
Stridulation
Grasshoppers:
One vein on each wing has file bearing ridges - scraper is on hindleg
Fast leg movements make file and scraper rub - vibrates wing
Crickets:
file on one wing, scraper on another
Hollow abdomen resonates sound
Tymbal of cicada
Contracting internal timbal muscles produces a clicking sounds as the timbals buckle inward
air filled cavity resonates
Fish sounds
Grunts/drums/croakers
grinding teeth - other stridulation
Drumming of swim bladder
Air release from anus
Body to object sound
Hares + rabbits - thump ground as warning
Woodpeckers
Chimpanzees - drum on tree trunks
Sound production is syrinx
Birds
two vibrating valves as opposed to 1 in mammals larynx
Independent control over both sides
Can sing 2 diff sounds at same time
Diff freq ranges on both sides
Sound production in whales and dolphins
Sounds in water more important - reduced vision - olfaction effected by slow diffusion
Comms/orientation/biosonar
Baleen whales - only comms
toothed whales - biosonar
Beam forming
Shape of mouth determines sound radiation
Can be modified in air
Harder in water - body tissue and water similar impedance - water passes through body tissue
Marine mammals can’t use same beam forming
Air filled cavities can reflect sound
Use oily fatty tissue with diff density to water to manipulate underwater sounds
Sound propogation
Low frequency for long distance
Diffraction bends sound around objects if WL is longer than object
Elephants communicate in dense forest with low freq
Sound reception
Pinna in mammals collects and funnels sound
Sound waves vibrate tympanic membrane
Ossicles of middle ear - vib motion - oval window of inner ear - pressure waves in fluid of coclea - detected by receptor cells in organ of corti
Outer hair cells - amplify weakest sounds
Interaural time difference
ITD
time diff of sound to ears - tell which direction sound came from
Interaural intensity difference
IDD
Diff intesity of sounds to each ear determines direction
Head creates a acoustic shadow
