Sensory Systems

Question 1

why do organisms have sensory stimulus and some examples?

Answer 1

to respond to their environment

• photoreception
• phonoreceptors
• mechanoreception
• EM spectrum
• thermo
• geo
• baro
• proprior

Question 2

how do invertebrates sense gravity?

Answer 2

differs between land/aquatic
statocysts - organs of balance
hollow fluid filled cavities lined with mechanosensory neurons - contain statoliths

Question 3

what are statoliths?

Answer 3

mechanoreceptors
different in different species - crystals in jellyfish
work by - fixing to hair cells or are free moving

Question 4

what are cilia used for?

Answer 4

sensing the environment

Question 5

how do flying insects balance?

Answer 5

combo of various sensory systems
- vision
- mechanosensation - angle of appendages, hair plates, joint load
halters - sense complex forces - act as gyroscopes

Question 6

how is IR used?

Answer 6

jewel beetles - metathoric organs - larva develop in trees killed by fire, liquid expands in presence of IR
ticks Haller organs sense IR

Question 7

how do invertebrate ears work?

Answer 7

key!!!
sense organs translate vbrations into electric signals
sound sensitive filiform hairs - tympanum

Question 8

how do owlet moths hear?

Answer 8

ears on either side of thorax

1. sound hits tympanum - vibration
2. receptors activated - two types - detects bats from 30m and move to reduce the incoming signal
   - emergency system prompts excecution of erratic maneovers in last ditch
3. signal sent to ganglion in thorax sending instructions to flight muscles

Question 9

how do mosquitoes hear?

Answer 9

1. soundwave hits hairs on antenna vibrations travel down
2. vibrations reach johnstons organ where theres lots of receptors tuned to hear sound of another mosquito in flight
3. amplify vibrations in anntena
4. electrical impluses travel to brain

Question 10

how do katydids hear?

Answer 10

one ear per foreleg, two eardrums each - vibrate in response to sound which causes the tympanal plate to jump up and down trasmitting vibrations to fluid in auditory vessicle which results in a wave rolling over crista acoustica where line of sensory cells pick out different frequencies and relay info to the brain
second internal channels transfers vibrations from thorax to traceal tube that runs from acoustic spiral to inner surface of tympanum
recieves same signal twice internal and external so can help determine the source of sound