click on photo to enlarge
Marine life during the Cambrian
explosion (~520 million years ago).
Image credit: Katrina Kenny &
Nobumichi Tamura.
A new study led by Adelaide researchers has estimated, for
the first time, the rates of evolution during the "Cambrian
explosion" when most modern animal groups appeared between 540 and 520
million years ago.
The findings, published online today in the journal Current
Biology, resolve "Darwin's dilemma": the sudden appearance of a
plethora of modern animal groups in the fossil record during the early Cambrian
period.
"The abrupt appearance of dozens of animal groups
during this time is arguably the most important evolutionary event after the
origin of life," says lead author Associate Professor Michael Lee of the
University of Adelaide's School of Earth and Environmental Sciences and the
South Australian Museum.