The Cambrian "explosion" was based on the fact that Cambrian rocks have many new organismal forms and body plans not found earlier in the fossil record. Analysi

The Cambrian "explosion" was based on the fact that Cambrian rocks have many new organismal forms and body plans not found earlier in the fossil record. Analysis of DNA sequences from currently living organisms suggests that this diversification occurred much earlier than the Cambrian. Scientists that focus on DNA infer that these diverse organisms simply failed to leave a fossil record. Meanwhile, many paleontologists don't like the idea of such substantial gaps in the fossil record.