In “570-Million-Year-Old Fossils Hint at Origins of Animal Kingdom” (Wired, December 22, 2011), Adam Mann reports,
New research suggests that fossils thought to represent some of the earliest multicellular life are instead single-celled, amoeba-like organisms.
The 570-million-year-old Doushanto formation, first unearthed in South China in 1998, contains tiny clusters of cells that look similar to animal embryos. During the embryo stage of life, cells become organized into tissues and organs, one of the hallmarks of all animal species.
However, when analyzed more closely, the cells caught in the act of dividing were not dividing the way animal cells do.
The significance of the reclassification into amoeba-like creatures is that a recent excuse for ignoring the significance of the Cambrian explosion has been removed.
When it was originally proposed, the animal-embryo hypothesis “was met with almost palpable relief” wrote Cambridge University paleobiologist Nicholas Butterfield in an accompanying commentary.
Why? Because it would enable paleontologists to build a claim that, in Mann’s words, “the theory of gradualistic evolution, which holds that life evolves slowly and steadily rather than in punctuated bursts”explained it all.
Not that the animal embryos would have been anywhere sufficient as a serious argument that the explosion never happened. but they would have provided a distracting claim for the textbook authors and the lecture rooms.