Light Used for Instant Signaling

a jelly fish with iridescent stripes is seen against a black background

Biological Strategy

Comb jellies

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Transform Radiant Energy (Light)

The sun is the ultimate source of energy for many living systems. The sun emits radiant energy, which is carried by light and other electromagnetic radiation as streams of photons. When radiant energy reaches a living system, two events can happen. The radiant energy can convert to heat, or living systems can convert it to chemical energy. The latter conversion is not simple, but is a multi-step process starting when living systems such as algae, some bacteria, and plants capture photons. For example, a potato plant captures photons then converts the light energy into chemical energy through photosynthesis, storing the chemical energy underground as carbohydrates. The carbohydrates in turn feed other living systems.

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Jellyfish

Subphylum Medusozoa (“serpent-haired monster animals”): Jellyfish, box jellyfish, hydrozoans

Medusozoans spend at least part of their life cycle in the medusa stage, where they form a bell-like shape with tentacles, allowing them to move freely. Within this subphylum, Class Scyphozoa (“cup animals”) include true jellyfish that have a thick, gelatinous body and live their adult lives as medusa. There are a few hundred species of scyphozoans. Class Cubozoa, often called “box jellyfish” get their name from their cube-shaped bodies, may be incredibly venomous, and have complex eyes, which are unusual among cnidarians.

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An enzyme called photoprotein in comb jellies produces light when calcium changes the enzyme's shape, releasing energy.

“In a firefly bioluminescence reaction, an enzyme known as a luciferase uses adenosine triphosphate (ATP) to activate a molecule called a luciferin. The product of this reaction combines with molecular oxygen to produce an excited-state oxyluciferin species. When oxyluciferin relaxes back to its ground state, energy is released in the form of light…Jellyfish-like animals called ctenophores—can do without [ATP to jump-start bioluminescence]. Instead, they use a luciferin of intrinsically higher energy and prepackage it with oxygen in an enzyme known as a photoprotein. Calcium activates the reaction by changing the shape of the photoprotein, which releases the invested energy in the form of light.” (Pepling 2006)

Last Updated August 18, 2016

References

Journal article

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