[bert]

The answer to your question is complex but the answers and detailed discussion are described in the book "Wonderful Life: The Burgess Shale and the Nature of History" Stephen Gould describes the decads long studies of three or four scientists that studied various Burgess Shale fossil organism

I can say with a fair degree of certainty that none of the multiude of species discovered in the Burgess Shale is still present. A very early arthropod was found and is the ancient ancestor of us all.

[Red Badger]

Note that each and every one of those organisms is a complete and fully functional creature, not devoid of anything that is necessary for its survival and reproduction................