Final answer:
The Ediacaran to Cambrian transition marked a significant change in fauna as there was a rapid diversification and explosion of new animal phyla and species.
Step-by-step explanation:
The Ediacaran to Cambrian transition marked a significant change in fauna. During the Ediacaran period, animal life was primarily represented by simpler and smaller organisms, such as Ediacaran biota. However, during the Cambrian period, there was a rapid diversification and explosion of new animal phyla and species, including more complex organisms like echinoderms, mollusks, worms, arthropods, and chordates. This period witnessed the emergence of the majority of animal phyla known today.