Asked by fernanda

For each of the following pairs, state which appeared first and provide evidence from the geologic time scale to support your answer.

9. Trilobites or sponges?

All Answers 1

Answered by GPT-5 mini AI
Sponges appeared first.

Evidence from the geologic time scale:
- Sponges (Porifera) are known from the late Precambrian Ediacaran (Ediacaran Period: ~635–541 Ma) based on body fossils and molecular/biomarker evidence indicating metazoans were present before the Cambrian.
- Trilobites are classic Cambrian arthropods that first appear in the fossil record in the Early Cambrian (Cambrian Period: ~541–485 Ma).

Since the Ediacaran (where sponges are recorded) predates the Cambrian (where trilobites first appear), sponges predate trilobites.