Geologic Time Project

Precambrian Time

Precambrian Time

4,560,000,000 B.C. - 542,000,000 B.C.

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.!!!!

Paleozoic Era - Life Diversifies

Cambrian Period

542,000,000 BC - 488,000,000 BC

Geologic Event - The supercontinent Rodinia broke up, splintering into smaller continents.
Biologic Event - Life evolved and diversified greatly, in an event called the Cambrian Explosion. Invertebrates and the first shelled animals evolved at this time.!!!!

Ordovician Period

488,000,000 BC - 444,000,000 BC

Geologic Event - The supercontinent of Gondwana(made up of most of the present day continents) got pushed south during this period.
Biologic Event - The first land plants appeared. They reproduced through spores and were small and primitive.!!!!

Silurian Period

444,000,000 BC - 416,000,000 BC

Devonian Period

416,000,000 BC - 359,000,000 BC

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.!!!!

Carboniferous Period

359,000,000 BC - 299,000,000 BC

Geologic Event - The Appalachians formed from Africa smashing into the east part of North America.
Biologic Event - The first reptiles evolved in this period. They adapted to live in drier areas where amphibians couldn't survive.!!!!

Permian Period

299,000,000 BC - 251,000,000 BC

Geological Event - At this time, the continents of Earth formed together to form Pangaea. Glaciers formed at the southern extremes, while desert appeared in the center of the supercontinent.
Biological Event - At the end of the Permian Period, and the Paleozoic Era, a mass extinction occurred. An estimated 96% of all species went extinct.!!!!

Mesozoic Era - The Time of Reptiles

Triassic Period

251,000,000 BC - 200,000,000 BC

Geologic Event - Towards the end of the Triassic, Pangaea began to split apart,with Africa slowly moving from the Americas.
Biological Event - The first dinosaurs and mammals evolved at this time. A type of plant called a gymnosperm evolved and became common during the Triassic also.!!!!

Jurassic Period

200,000,000 BC - 145,000,000 BC

Geologic Event - As Pangaea continued to split apart, new oceans appeared where the continents broke apart.
Biologic Event - Modern characteristics of fish appeared for the first time. The skeletons and fins among other things were very similar to today's fish.!!!!

Cretaceous Period

145,000,000 BC - 65,000,000 BC

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.!!!!

Cenozoic Era - Mammals Rise To Prominence

Tertiary Period

65,000,000 BC - 1,800,000 BC

Geologic Event - A lot of mountain building happened in this Period. The Rockies,Himalayas,and Alps were all created at this time.
Biologic Event- The Tertiary was when mammals specialized for their environments.They developed different types of teeth for different purposes.!!!!

Quaternary Period

1,800,000 BC - Present

Geologic Event - During the Quaternary, continental glaciers encroached upon the Northern Hemisphere then retreated many times.
Biologic Event - Humans evolved during the Quaternary,specifically a little over 100,000 years ago. They migrated out of Africa 50,000 years ago and slowly came to inhabit all of the continents save Antarctica.!!!!