The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another.

Earth: Facts about the Blue Planet Astrogeophysicists ... Period of the Proterozoic Era and the Cambrian Period of the Paleozoic Era is not as clear-cut as it was once thought to be.

The best time to see the ancient wonders that are horseshoe crabs is now, as they return to Delaware Bay beaches for spawning ...

These members of the class Chondrichthyes, or cartilaginous fish, are survivors from the Paleozoic Era with critical roles to play in ocean ecosystems. Here are 11 facts about the fascinating fish.

The Paleozoic Era is one of the most chaotic times in Earth's history. Find out why! The first era of our current eon, the Paleozoic Era, is probably the most deceptively fascinating time in Earth ...

Here are 14 dragonfly facts that may surprise you ... Some scientists theorize that high oxygen levels during the Paleozoic era allowed these dragonfly ancestors to grow to monster sizes.

3 min read During the Ordovician period, part of the Paleozoic era, a rich variety of marine life flourished in the vast seas and the first primitive plants began to appear on land—before the ...

The Paleozoic era's Silurian period saw animals and plants finally emerge on land. But first there was a period of biological regrouping following the disastrous climax to the Ordovician.

Horseshoe crabs first developed 540 million years ago in the Paleozoic era, more closely related to ... Here are a few fun facts about horseshoe crabs, according to the Ecological Research and ...