XII. The First Multicellular Eukaryotes

When did the oldest known fossils of multicellular eukaryotes appear?

• 565 million years ago

• 10 million years ago

• 1.2 billion years ago

• 535-525 million years ago

What phenomenon occurred roughly 535 to 525 million years ago?

• The appearance of predators

• The emergence of soft-bodied animals

• The evolution of single-celled eukaryotes

• The Cambrian explosion

What type of animals suddenly appeared during the early Cambrian period?

• Herbivores

• Filter feeders

• Scavengers

• Many phyla of animals

What defensive adaptations emerged during the Cambrian explosion?

• All of the above

• Heavy body armor

• Sharp spines

• Claws for capturing prey

What were the early animals in the early animal phyla primarily feeding on?

• Prey

• Scavenging

• Algae

• Plants