 The Cambrian explosion was a period of rapid diversification of life forms that occurred approximately 542 million years ago. This period saw the appearance of numerous new species, including those belonging to the phylum Cordata, which includes vertebrates. During this time, there were also many problematic fossils discovered, which had unusual body structures and could not be easily classified into any known group. However, recent research has shown that these fossils can provide valuable insights into the early evolution of animals. By examining the fossils' toponomy in homology, scientists have been able to gain a better understanding of how these organisms evolved and what they may have looked like when alive. This article was authored by Pei Yun Song.