THE PRECAMBRIAN TIME PERIOD

PRECAMBRIAN TIME PERIOD

• Precambrian time covers the vast bulk of the Earth's history.
• It started with the planet's creation about 4.5 billion years ago
• It ended with the emergence of complex, multicelled life-forms almost 4 billion years later.
• The Precambrian is the earliest of the geologic time periods.
• The earliest living organisms were microscopic bacteria.

PRECAMBRIAN TIME

• The first multicelled animals appeared in the fossil record almost 600 million years ago.
• Sponges, cnidarians, and annelids were the first muilti cellular animals to survive the Precambrian fall.
• It's thought the final stages of Precambrian time were marked by a prolonged global ice age.
• Earth was already more than 600 million years old when life began.
• About 3 billion years ago earth's atmosphere was virtually devoid of oxygen.

PRECAMBRIAN TIME

• At about 2.4 billion years ago oxygen was released from the seas.
• The oxygen that was released as a byproduct of photosynthesis by Cyanobacteria.
• The cnidarians included sea anemones, corals, and jelly fish.
• The earth took form about 4.5 billion years ago.
• The first continent was huge. It is called Rhodinia.

PRECAMBRIAN TIME

• Rhodinia formed about 1.1 billion years ago.
• Rhodinia contained the modern-day continents.
• About 350 million years later, the first ocean formed around Rhodinia.
• It caused the supercontinent to break into two parts.
• The first one-celled organisms formed during the Precambrian Era.

PRECAMBRIAN TIME

• All of the important work of the Precambrian made the Earth ready for what would come next.
• This eon covers almost 90% of the entire history of Earth.
• No one has found any rocks on Earth from this era.
• Only meteorites from space and moon rocks are this old.
• Most water vapor in the air has cooled and condensed to form a global ocean.

PRECAMBRIAN TIME

• The surface of Earth is still very active, but a few of the rocks that are forming now will survive to the present in spite of wind, rain, and remelting.
• geologists define the beginning of the Archean era as the age of the oldest rocks on Earth we can find today.
• Earth at this time is also very cold, with huge, bluish glacial ice sheets visible across the supercontinent.
• The Hadean era begins about 4.6 billion years ago with the formation of Earth from dust and gas orbiting the Sun.
• Some people think that an asteroid as large as the planet Mars hit Earth near the beginning of the Hadean era.

THE PRECAMBRIAN TIME PERIOD

ANIMALS IN PRECAMBRIAN TIME

PRECAMBRIAN TIME PLANTS

PRECAMBRIAN CLIMATE

PRECAMBRIAN MAJOR EVENT

PRECAMBRIAN TIME

RESOURCES

• www.nationalgeographic.com
• www.fossils-facts-and-finds.com
• www.cotf.edu