408.00 million years ago - 400.00 million years ago - Plants Appear on Land

Plants Appear on Land

The first plants to live on land appear in the late Silurian Period, around the margins of the seas. These moss relatives are very small and leafless. They have specialized tissues to transport water and nutrients, and to hold their stems upright without the buoyancy of water.

408.00 million years ago - 390.00 million years ago - First Sharks Appear

First Sharks Appear

The first sharks appear near Spain during the early Devonian Period. By the mid-Devonian Period, sharks are found throughout the world. Because the shark’s skeleton is made of cartilage, most shark fossils consist of only teeth.

420.00 million years ago - 390.00 million years ago - Great Glen Fault Forms

Great Glen Fault Forms

Lateral movement of Earth’s crust occurs in what is now Scotland, forming the Great Glen Fault, a fracture along which a rock formation splits and shifts. Rock split along this fault has been located in both Scotland and Newfoundland, Canada.

438.00 MILLION YEARS AGO - Ordovician Mass Extinction

Ordovician Mass Extinction

The second largest extinction of life on earth occurs at the end of the Ordovician Period, when glacier formation in the southern hemisphere lowers sea levels worldwide. More than 85 percent of animal species die.

440.00 MILLION YEARS AGO - Climate Change Causes Mass Extinction

Climate Change Causes Mass Extinction

Ice begins to cover the continents of the southern hemisphere, which are joined together and situated over the South Pole. This climate change causes the extinction of more than 85 percent of existing species.