Dr. Steven Novella

So what that indicates is that they were, these assemblages were in different places at different times.

So maybe the white sea assemblage evolved more in the part of the world that is now Canada before they sort of migrated over to the rest of the world.

And that's why they, or just that we are looking at these random little windows and it's very much, we have very few puzzle pieces, right?

So clearly the story is more complicated than there's just these three assemblages, you know, one, then two, then three.

But they also, you know, I don't know how surprised, but, you know, going back 40 years, you know, when we were first discovering these Ediacaran fossils, first of all, it was like they weren't even sure if they were real.

And then, oh yeah, these are definitely, you know, it's just like smudges.

And then you found, you know, better and better examples of, say, all right, clearly these are living things.

These look like animals.

But they're mostly two-dimensional animals living on the ocean floor, right?

They're from Flatland?

Yeah, basically.

Although later we discovered that some of them were just parts of animals.

It wasn't the whole animal.

But anyway, and they were mostly on the ocean floor.

They were mostly not mobile animals.

And the thinking was, well, this might have been like an offshoot or a separate multicellular kind of group of creatures that have no relationship to the Cambrian explosion.

But then we started to find...

primitive versions of even extant groups, you know, and groups from the Cambrian explosion in Ediacaran fossils.

So this is extending that.

So now we have found, oh, look, there's a bilaterian in this white sea assemblage of Ediacaran fossils, and there is evidence for, you know, the first evidence or the oldest evidence for sexual reproduction in animals.