Lecture 13 - Sensory Ecology Flashcards
What happens to molecular complexity with distance from the source?
It declines.
What are sensors?
Accessories to the nervous system that act as transducers.
Name an organism that uses an electrosensing.
Freshwater crayfish
What is flow detected by?
Surface hairs
Describe the detection of flow on coral planula.
Detect turbulence and flow using cilia.
Move towards the source of the sound.
Describe the detection of flow in copepods.
Use antennae.
Allows them to lock into the water that they’re surrounded by and detect small-scale vibrations in the water.
What is vibration detected by?
Accelerometers
Describe how crabs detect vibration.
Fuse sand grains together, creating a large crystalline structure which will vibrate relative to the crab.
Give some differences in fish eyes compared to the eye structure of other invertebrates.
- The lens is solid in fish
- Muscles move the lens forward and backwards, and do not stretch it.
- Fish have a fixed pupil.
What is the role of
a) Rods?
b) Cones?
a) Rods = vision in low light, deep sea.
b) Cones = resolution, colour discrimination.
True or false:
The ratio of rods and cones found in the retina is constant in fish.
FALSE.
The ratio of rods and cones varies depending on where fish live.
Describe the work of Siebeck et al (2010).
Described ultraviolet vision in shallow water species.
There are unique marks fish can see that are used for individual recognition, e.g. mate recognition.
Give the three pigments found in cones.
Describe the type of light they sense, and what sort of species they are found in.
1) Porphyropsin - yellow-red light, found in shallow species.
2) Rhodopsin - blue-green light, found in deeper water species.
3) Chryopsin - deep blue light, found in deep sea species.
Describe a visual adaptation in striped marlin.
The retina gives high acuity and colour recognition looking forward and upward, and blue vision for dim objects looking down.
Describe a visual adaptation of marlin and billfishes.
Can warm their eyes.
Eyes then work faster than cold-blooded prey species.
Describe a visual adaptation of lemon sharks.
Undergo an ontogenetic shift from Porphyopsin pigments as juveniles in mangroves, to rhodopsin pigment as adults in deeper waters.
Describe a visual adaptation of Engraulids (eels and salmons).
Can detect polarised light.
Use it as a compass, allowing them to detect the direction for long-distance migrations.
What is the name of receptors involved in electroreception?
Ampullary receptors
What are Ampullae of Lorezini?
Hair cells with a cap of conductive gel, allowing the fish to detect and electrosense.
What are Ampullae of Lorezini found in?
- Lampreys
- Sharks
- Coelocanths
- Sturgeons
- Bony fishes
Where can variation in the magnetoscent be detected in fish?
- From regional features, e.g. volcanic islands, with high levels of magnetic matter in rocks
- From local features, e.g. minerals in the seabed with magnetic signals.
Why are sharks and rays vulnerable to detection?
They have sensitive electroreception which disrupt the magnetic field.
Give some uses for chemoreception.
- Finding food
- Recognising food
- Detecting and avoiding predators
- Locating habitat
- Communication
Describe chemoreception structures in fish.
- Have paired olfactory chambers, each with incurrent and excurrent nostrils.
- Olfactory chamber lined with highly folded olfactory epithelium; high density of olfactory receptor cells as water passes through canal.
What is mechanoreception?
The detection of physical movement.
What is mechanoreception detected by?
Specialised cilia bundles that are orientated in different directions.
How does mechanoreception work?
Relative movement of kinocilium and stereocilia generate nervous impulse (greater when moving in the same direction).
How can animals detect the intensity of a disturbance in mechanoreception?
Have different lengths of stereocilia. If the disturbance is faint, the longest will move only. But intense disturbance causes movement of all the hair cells.
What is the lateral line system used for?
Motion detection (e.g. current detection, obstacles, prey, predators, shoalmates)
What is the benefit of the lateral line system being within a canal?
Means no flow is generated from its own swimming, but any other movement disturbs the water flowing naturally over the skin, generating differential movement of water.
What is an otolith?
- Free floating
- High density of hair cells arranged in bundles pointing in different directions around the otolith.
- Otolith vibrates relative to the fish; fish can detect direction of the sound.
