Return to Geology Index PagePaleozoic Era
The Paleozoic era began when the Precambrian era ended. There was an explosion of life marking the beginning of the Paleozoic. Paleozoic means ancient life. There are six periods within the Paleozoic Era. These periods include the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
Cambrian 570 mya to 500 mya
The Cambrian Period lasted for 70 million years. The Cambrian is the first period of the Paleozoic Era. The Cambrian is quite different from the Precambrian in that the animals could see, think, and they had exoskeletons. All life existed in the oceans at this time because the ozone layer was not developed to withstand ultraviolet rays from the Sun. The most advanced animal of this period was the trilobite. The Cambrian is known as "the age of the trilobites."
Ordovician 500 mya to 440 mya
The Ordovician Period existed for 60 million years. The Ordovician was shorter than the Cambrian period. All life still existed in the ocean because of the lack of proper ozone levels. The trilobite became larger and smarter during this time. The major life form of this time period was the shell fish. The Ordovician is called "the age of the shell fish."
Silurian 440 mya to 400 mya
The Silurian Period lasted for 40 million years. The Silurian marks the first time that life existed on land. These life forms were simple plants such as Psilophyton, a vine-type plant. Plants of this period did not possess leaves or flowers. The Silurian is called "the age of the first life on land." Ozone levels have reached the required thickness to protect life on land from now on.
Devonian 400 mya to 350 mya
The Devonian Period lasted for 50 million years. The Devonian is called "the age of the fishes." Two types of fish developed during this time period: jawless and jawed fish. The jawless fish were armor plated with bones and used suction to feed through their mouths. Some jawed fish developed lungs, and the first animal life walked upon the land at this time. Sharks also made their début at this time.
Carboniferous 350 mya to 280 mya
The Carboniferous Period, also called the Mississippian and Pennsylvanian Periods, lasted for 70 million years. The Carboniferous is often called "the age of swamps and coal." During this time period much of the land was covered by swamps and seas. The climate was extremely warm during this period. Giant insects and plants dominated this period. Much of the coal supplies world-wide originated from this period.
Permian 280 mya to 225 mya
The Permian Period existed for 55 million years. The Permian period saw the rise of dinosaurs and mammals. It is often called "the age of mass extinction" or "the age of amphibians." Giant amphibians ruled the land during this period. This period marks the end of the Paleozoic Era when an asteroid around 10 miles in diameter struck the North American Continent at Hudson Bay, Canada. The asteroid strike was so devastating that 98% of life on Earth was wiped out! This destruction was caused when dust from the impact circled the globe via the jet stream and blocked out the Sun for many years, freezing most life on Earth.