Jellyfish Gone Wild — Text-only | Flash Special Report
Evolution

Plying the world’s oceans for more than 500 million years, jellyfish and jellyfish-like animals were among the first animals to inhabit the Earth.  They were also probably among the first animals to break the shackles of a stationary lifestyle and swim freely through the primordial seas.

Jellyfish and other jellyfish-like animals evolved along entirely different evolutionary pathways from one another.  This evolutionary redundancy reflects the adaptability and success of the transparent, gelatinous body form.

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Caption/Credit:

OLDER THAN DIRT
This jellyfish fossil is more than 500 million years old, the oldest jellyfish in the fossil record to date. Fossils like this one and genetic studies indicate that jellyfish and jellyfish-like creatures have exerted important influences on marine ecosystems for millions of years.
Credit: J. Hendricks and B. Lieberman, University of Kansas

NO BONES ABOUT IT
Fossils of boneless jellyfish are rare, but do exist. This jellyfish fossil is from the middle Cambrian.
Credit: J. Hendricks and B. Lieberman, University of Kansas