For this reading guide, we're just looking at the sections of the chapters about rocks. The topic guide on Paleozoic Life picks up the sections of the chapters on critters. The topic guide organizes ...

The earliest evidence of multicellular life is the enigmatic acritarch, which probably represent a resting form of an algae (in stressful environments, some organisms grow a protein coat, forming a ...

The Paleozoic era began 530 million years ago when the Earth woke up from an ice age. This era lasted for 289 million years, ...