Grace Crocker, Staff Writer
Just recently, a new abundance of marine fossils from the Cambrian explosion were found in China. When life started on Earth, organisms didn’t range much from bacteria and multi-celled algae. In the Precambrian era, about 600 million years ago, scientists estimate that evolution kicked in to create new life forms. Some of these life forms created all the way back in the Precambrian era can be linked to creatures we know today, though others are so far unlinked. It is probable that those unlinked creatures have seen extinction along the genetic line.
About 550 million years ago, it is theorized that an explosion of diversification among creatures on Earth resulted in most of the lifeforms we see today, according to scientists. This explosion of evolution occurred during the Cambrian era, giving it the name the “Cambrian explosion.” Despite being referred to as an explosion, it is speculated that this great amount of evolution happened over the span of 30 million years; some stages might have taken about 5 to ten million years. There is still some debate as to what sparked the Cambrian explosion in the first place. One theory is that life simply and coincidentally found the genetic tools to create other life forms. Another idea suggests that predation, naturally occurring environmental changes, and a new abundance of nutrients reaching the ocean prompted a snowball of evolution.
For the past four years, fossils from this era in history have been discovered by researchers from Northwest University and Guizhou University. Around 700 miles southwest from Beijing, researchers Xingliang Zhang and Dongjing Fu from Northwest University lead the charge.
“Its preservational quality is mind-blowing,” said Martin Smith, a paleontologist at Durham University. Although he wasn’t a part of the expedition, he claims that the new site is remarkable for “capturing a profoundly important time in evolutionary history in such incredible detail,” according to The Guardian. “If you sent a time traveler back to the Cambrian period armed with a camera and an x-ray machine, the images they’d come back with would be nothing compared to these fossils, which preserve detail finer than a human hair,” he adds.
Research on the Cambrian period originally started back in 1909, when the Burgess Shale in British Columbia was discovered. The Burgess Shale was the first place where brachiopod, trilobite, mollusk, and echinoderm fossils were discovered. The fossils found in this shale were so well preserved, internal organs, and eyes could still be seen after millions of years. All other sites since then containing Cambrian fossils have been shale beds. Now, a new site close to Danshui River (referred to as the Qingjiang biota) in Hubei Prefecture, China, is reported to contain the best fossils that have been found to this day. The fossils are better preserved than even the Burgess Shale fossils, and dozens of new, never-before seen creatures are being discovered. So far, 4,351 fossils have been dug up; out of the 101 species extracted, 53 of them are completely new, according to The Guardian. Some of the creatures that have been dug up include sea anemones, jellyfish, coral, sponge, comb jellies, arthropods, mud dragons, and microscopic fossils.
Researchers infer that, in order to be this well-preserved, the fossils must have been very deep underwater. So deep, in fact, that a lack of oxygen wouldn’t sustain anything that would decompose these creatures. The bodies would end up at the bottom of the sea and become covered by sediment, waiting years to be pushed up by naturally occurring environmental changes to become land. That land then became the shale bed, Qingjiang biota, to be dug up and rediscovered.
“These fossils help us to piece together the steps that evolution took as animals evolved from whatever squishy blob represents their common ancestor to the rich diversity of lineages alive today,” Smith goes on to say. “Because some of the preserved organisms are much simpler than their living relatives, they help us to tease apart how complex organs such as brains could be assembled through blind evolutionary processes.”