Vestigial structures are often homologous to structures that are functioning normally in other species. Therefore, vestigial structures can be considered the evidence for evolution, the process by which beneficial heritable traits arise in populations over an extended period of time.
Only phylum bryozoans were not present during Cambrian period. It is an extensive fossil that did not appear in Cambrian nor pre-cambrian rocks. Bryozoans are found in the early Ordovician period. It could have probably existed during the Cambrian period but were soft-bodied or not preserved.
