Era Time

Millions of Yrs Ago

Began — Ended

Major Geological Events Major Biological Events Canadian Landforms Created
Precambrian

(earliest life)

4600      570

– volcanoes erupted, many cycles of mountain building and erosion – 1st single-celled organisms

– 1st multi-celled organisms

– Canadian Shield formed

Paleozoic

(ancient life)

570        245 – periods when large parts of North America were covered by shallow seas – 1st insects

– Age of Amphibians and Fish

– large swamps

– 1st plants & animals appear on land

– Appalachian Mountains formed

Mesozoic

(middle life)

245        66 – shallow seas in interior of North America at times – Age of Reptiles (dinosaurs)

– 1st flowering plants

– 1st birds and mammals

– Formation of Rocky Mountains begins

– Innuitian Mountains formed

Cenozoic

(recent life)

66     present – ice sheets covered much of North America

– continents take on present shape

– human beings develop

– Age of Mammals

– modern forms of life evolved

– Formation of Rocky Mountains completed
author avatar
William Anderson (Schoolworkhelper Editorial Team)
William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

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