Major Geological Event - Earth formed from
gravity squishing together a bunch of space dust, rock, and ice. A bunch of factors(radioactive decay, rock impacts) generated a lot of heat,which melted the Earth. Denser materials like iron formed the core of the Earth, while less dense materials like silicon becoming the mantle and crust. The atmosphere formed from the gases released from volcanoes erupting. Early life slowly increased the oxygen content of the atmosphere. Oceans formed from the atmosphere raining down on the surface.
Major Biological Event - The first life forms appeared. They were basic single celled organisms that used photosynthesis to make food. Later, simple life resembling jellyfish,worms, and corals evolved. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSHq99fRW7Rcpu2ynkBeAPtd_nw4pX4jkD8M6eMFQkcEuUV-3qXKw
Geologic Event - The continent of Laurasia formed. It was made up of present day Siberia, Europe, and North America.
Biologic Event - The first forests were made up of short and small trees and bushes. They were populated by insects,spiders,and centipedes. The very first amphibians evolved. They had fishlike features but had legs. At the end of this period, two mass extinctions struck the Earth, killing off armored and jawless fishes. https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQWR5qXkLA1Mpn6zg6e5vm6UNlNuyJ0jI0G0bL-B9FGB3pi5cX5
Geological Event - Shallow seas created massive swamps, reminiscent of the Paleozoic Era. These swamps created the coal deposits in Canada and the U.S.
Biological Event - There was great variety in the kinds of dinosaurs during the Cretaceous. Massive herbivores stomped around chewing the leaves of trees,while at the same time smaller dinosaurs developed plated skin to protect against predators. The dinosaurs and many other animals went extinct at the end of the Cretaceous,marking the end of the Mesozoic. The mass extinction is largely believed to have been caused by a meteorite crashing into the Earth. http://t2.gstatic.com/images?q=tbn:ANd9GcSttmn4SMDhTdLmoLmMCHd_52nHMGZCl6CrwmQI3HzvBdIqkJhs3w