Sponges are outliers in biology’s big bang, the Cambrian explosion. Their embryos appear in Precambrian strata, leading some to consider them primitive.
Gregory Retallack is a kind of maverick paleontologist, who endorses a fringe hypothesis that Ediacaran organisms were not marine but terrestrial lichens.
It’s interesting to see what Derek E. G. Briggs is willing to admit about the Cambrian explosion.
The strength of a theory can be gauged by how well it stands up to attacks and how well it incorporates new evidence.
To explain away the Cambrian explosion has been and remains a high priority for Darwinists.