Precambrian, meaning being the earliest era of geologic history

Having no plants or animals, only rock, desert, water and ice

Significant events: being latter Precambrian, heat dissipated enough to allow the continental crust to form; crustal rifting, mountain building, and volcanic activity then dominated,

Paleozoic: meaning ancient life

Animals, life: Included marine life such as trilobites, fish, and sea sponges, Land life also evolved such as amphibians and reptiles.

Significant events: Six periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian

The most recent of the subdivisions of animal history

Having Ferns, horsetails, and shrubby flowering plants

Having mammals, fish, birds

Significant events: mass extinction, the rise of mammals, changes in the climate, and the movements of the continents into their present position.

Mesozoic, means 'middle life' this is the time of the dinosaurs. It ended with a massive meteorite impact that caused a mass extinction, wiping out the dinosaurs and up to 80% of life on Earth. 

The early Mesozoic was dominated by ferns, cycads, ginkgophytes, and other unusual plants.

Having dinosaurs, specific types being Triceratops, Stegosaurus, Velociraptor

Significant events: The Appalachians were subjected to erosion, the products of which were deposited along the Atlantic coast. Also Flying reptiles and birds first appeared during the Mesozoic Era.