Bioluminescence is the generation of light by living organisms,
including deep-sea species of squids, octopus, worms, and mollusks,
and the firefly in the air.
The light created by the deep-sea life is produced by special
cells or by bacteria that live within the fish. Some fishes have
lights of different colors and on various parts of the body that
the light displays are unknown, they presumably function as a
form of communication.
Some predatory species use bioluminescence to lure prey. Deep-sea
angler fish, have log filaments with a light on the end dangling
over the top of the head. These anglers feed on other fishes that
mistake the light for small prey and swim into the angler's enormous
The light produced by the firefly is said to be "cold,"
because the efficiency of the utilization of the energy is so
great that little of it is converted into heat. The processes
involved in this light production have been imitated in the laboratory
by mixing together in a test tube the four substances isolated
from the lantern of fireflies. These are luciferase, and enzyme
that acts as a catalyst; luciferin, an organic substance which
emits light when oxidized; magnesium ion; and adenosine triphosphate,
a compound which occurs in all organisms and is the immediate
source of muscular contraction. When these four substances are
mixed in the test tube, firefly light is emitted.
The light organs of the firefly, located on the underside of the
sixth and seventh abdominal segments, are apparently derived from
fat-bodied cells. They are richly supplied with nerves and tracheae
which supply the oxygen necessary for light production. It is
generally accepted that the light attracts opposite sex. Males
and females of each species have a characteristic flash enabling
them to find each other.
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