bioluminescence and electric organs

two types of electric organs

• exapted muscles electrocytes

  • eels

  • rays

  • Peter’s elephantnose fish

• exapted nerve electrocytes

  • ghost knife fish

electrocyte function

• non-contractile muscle has developed greater control over ion gradients (Na/K) in/out of the cell

• these flat cells generate a real, but small, electrical differential

• stacks are called electropaxes

volts vs amps

volt: the differential in electrical potential

amp: the volume of electrons moving across that difference

shocker

these fish use the electrocytes for prey capture or defense

• stargazers

• electric eel/ ray/ catfish

sensor

these fish use the electrocytes for navigation or communication

• elephant fish

• knifefish

• electric skates

how many different lineages of electric generating clades are there?

6

bioluminescent strategies

• bacteriogenic- symbiosis with glowing bacteria

  • pinecone fish

  • anglerfish

• autogenic- created by vertebrate internal physiology

  • midshipmen

  • stoplight loosejaw

  • kitefin shark

photopores in bacteriogenic

• a bacteria, generally Photobacterium or Vibrio sps, is housed inside a light generating structure

• often backed by a layer of guanine crystals to reflect the light out

luciferin

• all autogenic bioluminescent verts use luciferin and luciferase to glow

• this enzyme system releases photons when digested