Complex Life May Have Started On Land, Paleontologists Suggest
Complex life may have actually started on land, instead of in the sea, according to a provocative study, which defies conventional wisdom about evolution.
The earliest stage of life forms may have actually appeared on land before the oceans filled with creatures that swam, crawled, and burrowed in the mud, reports NPR.
Conventional wisdom about the evolution of life comes from fossils that date from the Cambrian explosion, which happened about 530 million years ago. This era is when complex life suddenly emerged in the sea with many different life forms.
But the theory that life may have started on land comes from paleontologists studying Ediacarams, which are fossils discovered on land that predate the Cambrian explosion. The majority of scientists assume that these Edicarans were predecessors of jellyfish, worms, and other invertebrates, but Greg Retallack with the University of Oregon has his doubts.
Retallack is not the first to question the conventional theory either, notes Nature.com. Paleobotanist Jane Gray began arguing against the conventional theory in the 1950s. Gray asserted that the presence of life began on land, though she didn’t get many grants for her research, because she was female, ferocious, and an advocate to an unpopular theory.
Like Gray did before him, Retallack is building the case that Edicarans weren’t animals, but instead a king of fungi or lichen. His latest research also contends that, unlike conventional theory states, these Edicarans lived on land, under the sky, instead of on the sandy beds of shallow, sunlit seas.
He made the conclusion by studying a series of Edicarans that were found in Australia, discovering that the rock encasing them is made of ancient soil, not marine mud. Retallack stated:
“What I’m saying for the Edicaran is that the big [life] forms were on land and life was actually quite a bit simpler in the ocean.”
Do you believe the theory that life may have formed on land, then evolved into the sea? Is there ever a way that we will truly know what happened, or will we continue to come up with new theories without knowing which one may actually be correct?