Listen to the March 7, episode of Science News Flash for more details on this discovery. But in reality, this discovery creates significant problems for the evolutionary paradigm. Remember, it is presumed that Pikaia is a primitive chordate. Instead of observing the sequential appearance of primitive chordates first, followed by more advanced chordates, the fossil record actually shows the simultaneous appearance of primitive and advanced chordates.
This pattern is unexpected from an evolutionary perspective. In fact, the Cambrian explosion is reminiscent of creation day 5 in Genesis, when God commands the waters to teem with life. In , researchers discovered fossil chordates in rocks in China that are 10 million years older than Pikaia!
Chordates have been around for a long time — since at least the very early Cambrian. Some chordates evolved skulls and a bony spinal column, becoming the lineage known as vertebrates — of which humans are a small part.
Is Pikaia an arthropod? Subscribe to our newsletter. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email.
Bob Strauss. Science Writer. Updated April 08, Featured Video. Cite this Article Format. The study examined Pikaia fossils using a range of imagery techniques, including scanning electron microscopy, to reveal fine details.
With no backbones or other mineralized elements, Pikaia would stand no chance of preservation in normal conditions outside exceptional sites like the Burgess Shale. We hope that, with continuing explorations and field work studies there, other species will be discovered allowing us to refine our understanding of the early history of our own group.
The confirmation of Pikaia as a chordate is the latest in a recent string of Burgess Shale discoveries. In November , evidence of fossilized tracks of a large predator known as Tegopelte were published, and in January a bizarre tulip-shaped creature named Siphusauctum was described for the very first time.
This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page. Our selection of the week's biggest Cambridge research news and features sent directly to your inbox.
Enter your email address, confirm you're happy to receive our emails and then select 'Subscribe'. I wish to receive a weekly Cambridge research news summary by email.
The University of Cambridge will use your email address to send you our weekly research news email. We are committed to protecting your personal information and being transparent about what information we hold.
0コメント