In Professor McMenamin's view the creatures were
beginning to evolve senses and even crude brains.
Professor Jim Ogg, secretary-general of the
International Commission on Stratigraphy (ICS), filled in some
of the background: 'There's always been a recognition that the
last part of the Precambrian is a special time before the first
shelled animals appeared, when there are these weird, mesh-like
creatures of uncertain affinity'.
The Ediacaran period begins at the end of the
last ice age of the 'Snowball Earth', or Cryogenian period, a
term given to a series of glaciations that covered most of the
planet between 850-630 or 600 million years ago (see related
One theory proposes that these climate shocks
triggered the evolution of complex, multi-celled life. Professor
Ogg said many of the new life forms that appeared in the Ediacaran
seem to be simple organisms, probably related to present-day
'They appear to be lying flat on the seafloor
and people think they may have had photosynthetic symbiosis
much like corals do today. These organisms were probably ripped
to shreds when the first predators came along. That probably
happened in the Cambrian period.'
A life cut short
'Ediacarans were on a trajectory in which they
would have developed into intelligent life, but it was cut short,'
Professor McMenamin agreed in a report published in the New
'They were developing ways to pick up environmental
cues and process that information in ways that would allow them
to adapt better and leave more progeny. Ediacarans represent the
first evidence of anything like intelligence on Earth.'
Other researchers have dismissed his ideas,
claiming the Ediacarans were in fact the forebears of primitive
animals such as jellyfish. For decades the accepted view was that
Ediacarans were animal ancestors. Then in 1982, Adolph Seilacher,
from the University of Tubingen in Germany, announced that
Ediacarans were not animals at all but a now-extinct class of
life by themselves.