A 300-YEAR-OLD mystery of a creature that could apparently die and come back
to life has been solved by Californian researchers.
Brine shrimp embryos called Artemia form cysts which play dead for
years before bursting into adult life. Until now, it has been impossible to find
any sign of activity in the cysts, so ever since Voltaire’s time scientists have
speculated that the embryos must stop their metabolism completely. But this
would defy one of the accepted definitions of life—that living organisms
require a continuous expenditure of free energy. “This is a central axiom of
biology,” says James Clegg…
