Final answer:
Ediacarans evolved during the Ediacaran period, a geological era from approximately 630 to 542 million years ago, marking the rise of multicellular organisms with the emergence of diverse fauna and flora following this period.
Step-by-step explanation:
The Ediacarans evolved during the Ediacaran period, which is the uppermost division of the Proterozoic Eon of Precambrian time, spanning from approximately 630 to 542 million years ago. This period saw the advent of multicellular organisms with tissues. The most notable characteristic of these ancient animals was that they were generally flat and soft-bodied. Though many of these creatures were only a few millimeters to centimeters in length, some, like the feather-like forms, could grow to over a meter in length.
One of the key aspects of the Ediacaran biota is that despite their simple body plans, they were the precursors to more complex life forms. By comparison, approximately 500 to 600 million years ago, a vast array of different fauna and flora emerged, including organisms that are now classified into the three domains: Archaea, Bacteria, and Eukarya, the latter featuring organisms containing nuclei such as animals and plants.