ELECTRORECEPTION IN ELASMOBRANCHS (SUMMARY)

Student: Ioannis Lioritsis (Bio 747)

1.) History of Electroreceptors

- First evidence of electrosensitivity dates back to 1935. - In 1958 Lissmann names the ampullae of Lorenzini. - Later, experiments verify the existence of the new class of specialized receptors. They were named "electroreceptors".

2.) The Physical Stimulus for Electroreception

- Elasmobranchs use the electric fields surrounding them for navigation and identification of their environment.

3.) Ampullae of Lorenzini

3.1.) Anatomy

- The ampullae of Lorenzini are electroreceptive units in sharks. - There are jelly-filled canals found on the head of the animal. - The ampullae is at least as important to an animal as its eyes, ears and the lateral line.

3.2.) Physical Characteristics

- The ampullae are sensitive to weak electric fields (Murray).

4.) Role of electroreception in Behavior

- Experiments by Kalmijn in 1971 to enlighten feeding responses of sharks. - Detection of electric fields directly influences the feeding response of the animals.

5.) Significance of Research

- Electroreceptors enable elasmobranchs to search and navigate through the earthÕs ocean and seas. Electroreception allows these animals to sense the presence of their victims.