Photograph by Joel Sartore, National Geographic Photo Ark The earliest multicelled animals that survived the Precambrian fall into three main categories. The simplest of these soft-bodied ...

Paleontologists now know that the Precambrian actually did swarm with ... group of organisms called eukaryotes, which include animals, plants, fungi, and protozoans. The evidence for the oldest ...

So what exactly were these highly diverse Precambrian creatures? Plants, animals, or of another kingdom entirely? Nearly all scientists today agree that they were soft-bodied marine-dwelling animals.

Nevertheless, their proliferation “set the stage” for the animal kingdom to evolve before they died out, the researchers wrote in a new report, published in the journal Precambrian Research.