June 29, 2010
Some tortoises and whales are known to live for more than a century. Some people do too! But
scientists have discovered a type of jellyfish that may be able to live forever.
The Turritopsis
nutricula jellyfish can go back to polyp form, a
jellyfish's childhood stage, after it has grown into an adult. In other words, these adult jellies can turn back into baby jellies and grow up all over again.
Researchers think this special jellyfish species can repeat its life cycle
indefinitely. That means it's possible for these jellies to live forever by defying old age.
But T. nutricula cannot defy death entirely. Like other animals, they may be killed by diseases or
predators. Still, the
jellyfish are considered "biologically immortal" because the animals could live forever in a controlled environment.
How do they do it?
All living creatures are made up of millions of tiny cells, which are often called the "building blocks of life." Different cell types make different parts of an
animal's body. But the
T. nutricula can change one type of cell into another type of cell. That's called trans-differentiation.
Animals that can
accomplish trans-
differentiation are rare. There are a few animals that can regrow certain body parts. Salamanders, for example, can
re-grow their limbs. But these jellies are the only animals known to re-grow their entire bodies.
Scientists are
fascinated by this
discovery. Researchers are now studying how these
creatures repeat this process over and over.
Growing in Numbers
The T. nutricula used to live only in the Caribbean. Now they can be found in every ocean in the world. Scientists believe that warmer waters have allowed the jellyfish to move beyond their natural range.
Creatures who move to areas they didn't inhabit before are called invasive species. Since these
jellyfish don't die naturally, their population is growing quickly in their new
habitats.
From Scholastic.com
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