senses Flashcards
roles of sense
- sensory input to processing in the brain to motor response (behaviour )
sensory modalities
-uses a range of different senses in different ways in which a (physical) environmental stimuli can be detected by an individual
-examples are: sight, taste, smell, touch, hearing, echolocation (extreme hearing), electroreception (electric impulses), magnetoreceptoion, pressure and proprioception (perception of movement)
sensory ultraviolet light
-pollinating insects can detect UV light due to its short wavelength
-atlantic puffer and bluethroat have UV light in them
cone cell types in birds and humans
-humans: 3 types of photoreceptors that translate light into nerve impulses, these travel up the optic nerve to the brain
-birds: have 4 types of cone cells and can see UV
UV signals involved in sexual selection
-bluethroats had covered their UV patch with sunblock which reduced the amount of males reproducing with them
why is UV vision important
-peacock feather, the male attraction
-UV can allow predatory birds to detect urine trails of small animals
olfaction: moths
2 types: pheromones and a general odour sensing systems e.g. food-derived odour
-male emperor moths can detect females from miles away due to large male antennae (which detect the pheromones)
touch star-nosed mole
-lives underground in marshy soil
-tiny eyes but highly modified nose
-the ‘star’ is not equally sensitive and each appendage is not processed equally
-11 appendages
-appendage 11 has 7% of the eimers organs but more than 10% of the nerve fibres
-star takes up most amount of brain cortex
what’s the eimers organs in a moles nose
specialised structures which changes in pressure
which in the moles nose, are the most important appendages
-10 and 11, found close to the mouth therefore important so they don’t consume something bad for them
hearing in noctuid moths
-moths ears are simple
-just consist of air sacs and 2 receptors (can’t detect pitch) in which signals are picked up and transferred to the thoracic ganglia and up to the brain
neural activity of receptors: moths and bats
-can detect bat sonar and direction of sound which helps moth escape the bat
neurology of moth ears
-bat ultrasound signal-> tympanum vibrates-> mechanical stimulation of receptor cells (both)-> stretch-sensitive channels open in membrane->Na+ flow in and change the electrical charge inside cell creating an action potential-> therefore avoiding action by moth
advantage of 2 sensory cells
cells are’t equally sensitive so increases range of the moths hearing
why do bats have squeaky voices
-a wave can only detect an object that is larger than half the wavelength
-so high pitched sounds are needed to detect small insects
-bat species that specialise on larger insects have deeper calls
how do oilbirds communicate
-they roost and breed in caves and can navigate in total darkness using echolocation
-they use available clicks with longer wavelength meaning they can only distinguish relatively large objects
what is stimulus filtering
-universal feature of sensory systems that typically focuses in information relevant to the animals survival or reproduction
-this occurs so the animal doesn’t get overwhelmed
ormia flies and how they stimulus filter
-female deposits eggs on male crickets
-these eggs hatch and larvae burrow in cricket and then feed on the crickets malt and then turn into adult flies
-cricket doesn’t survive long after as the the gut insides are deposited into cricket
tinbergan’s herring gull : responding to signals
-releaser stimuli set off fixed action patterns (pecking)
-highest relative pecking response for an artificial object that was red, mimicking the red dot on the gulls beak
neural mechanisms in brain in gulls
-brain of the chick has a mechanism for detecting the relaxer stimulus and triggering and the begging FAP
-the FAP of the chick is instinctive, the brain circuitry behind the FAP is encoded in the chick’s genes rather than learned
parasites exploiting releaser behaviour
-atemeles beetles are parasites in an nests
-ant responds to beetle by feeding them
-large blue Butterly caterpillars parasite ant nests by preying on larvae
