L 22 Electric Fishes

Question 1

How are electroreceptive fishes different from non electroreceptive fishes?

Answer 1

Electroreceptive fishes normally use electrical signals present in the environment: specialized receptors present

Question 2

Are teleost non elcetroreceptive?

Answer 2

yes

Question 3

What does being a non electric fish mean?

Answer 3

Electric organs are absent, but there is passive electroreception. By passive, it means they may react to external electric stimuli.

Question 4

What does being an electric fish mean?

Answer 4

specialized organ is present, active electroreception.

the fish produce or generate electrical stimuli to which their own electroreceptors are sensitive

Question 5

What are two kinds of external pit organs?

Answer 5

1. tuberous electroreceptive organs

2. ampullary electroreceptive organs

Question 6

Eels, catfish and lungfishes have specialized sensory receptors that allows them to do what?

Answer 6

detect minute electrical currents in the water

Question 7

What is the tuberous electroreceptive organ like?

Answer 7

Covered by loosely packed epithelian cells that allows electrical current to flow between the cells

Question 8

What is the ampullary electroreceptive organ like?

Answer 8

Supporing cells in the ampullary organs produce a highly conductive jelly that fills the canal linking the sensory cells to the surrounding water

Question 9

Who is Stefano Lorenzini?

Answer 9

Italian anatomist who discovered the ampullae of lorenzini of elasmobranches.

It’s located primarily on the snout, and also on the lower jaw and just anterior to the first gill opening

Question 10

Why may the ampullae be important?

Answer 10

It’s important for locating hidden prey by sensing electric fields produced by muscular movements, i.e respiration.

Question 11

What is evolutionary convergence?

Answer 11

structures that has evolved independently

Question 12

What kind of attributes do active electroreceptive fishes share?

Answer 12

generally slow moving or sedentary, active at night and live in murky waters of low visbility. They have thickened skin that acts as a good insulator and reduced eyes.

Question 13

How are brains from fishes with active electrosensory systems different from other fishes?

Answer 13

the cerebellum are generally enlarged.

Question 14

What type of fish has strongly electric forms?

Answer 14

torpedo or electric rays, can deliver about 220 v

electric catfish 350 v
electric eel 350 v-650v

Question 15

What may be the function of strong electric organs?

Answer 15

to stun prey and discourage intruders or predators

all types of electric fishes live near the bottom, near turbid water

Question 16

What are some weakly electric forms?

Answer 16

skates, elephantfishes and knifefishes

Question 17

what may be some function of being wekaly electric?

Answer 17

function in location and id of nearby objects and in electrocommunication

Question 18

Who is H.W Lissman

Answer 18

proposed that the function of weakly electric fishes was to locate nearby objects by detecting distortions that are produced in animal’s own electric field

Question 19

What is a characteristic of weakly electric fishes’ bodies?

Answer 19

an elongate stiff body, with locomotion generated by a long dorsal fin to help ensure symmetry of the electric field

Question 20

How may electric communication occur?

Answer 20

Occurs when one fish, emits an electrical signal that evokes a behavioral response from another fish

Question 21

How may electrocommunication in weakly electric fishes be multi functional?

Answer 21

used in courtship, aggression, appeasement, to warn an impending attack